src/libsyntax/print/pprust.rs

   1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 pub use self::AnnNode::*;
  12
  13 use abi::{self, Abi};
  14 use ast::{self, BlockCheckMode, PatKind, RangeEnd};
  15 use ast::{SelfKind, RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
  16 use ast::Attribute;
  17 use util::parser::AssocOp;
  18 use attr;
  19 use codemap::{self, CodeMap};
  20 use syntax_pos::{self, BytePos};
  21 use parse::token::{self, BinOpToken, Token};
  22 use parse::lexer::comments;
  23 use parse::{self, ParseSess};
  24 use print::pp::{self, break_offset, word, space, zerobreak, hardbreak};
  25 use print::pp::{Breaks, eof};
  26 use print::pp::Breaks::{Consistent, Inconsistent};
  27 use ptr::P;
  28 use std_inject;
  29 use symbol::{Symbol, keywords};
  30 use syntax_pos::DUMMY_SP;
  31 use tokenstream::{self, TokenStream, TokenTree};
  32
  33 use std::ascii;
  34 use std::io::{self, Write, Read};
  35 use std::iter;
  36
  37 pub enum AnnNode<'a> {
  38     NodeIdent(&'a ast::Ident),
  39     NodeName(&'a ast::Name),
  40     NodeBlock(&'a ast::Block),
  41     NodeItem(&'a ast::Item),
  42     NodeSubItem(ast::NodeId),
  43     NodeExpr(&'a ast::Expr),
  44     NodePat(&'a ast::Pat),
  45 }
  46
  47 pub trait PpAnn {
  48     fn pre(&self, _state: &mut State, _node: AnnNode) -> io::Result<()> { Ok(()) }
  49     fn post(&self, _state: &mut State, _node: AnnNode) -> io::Result<()> { Ok(()) }
  50 }
  51
  52 #[derive(Copy, Clone)]
  53 pub struct NoAnn;
  54
  55 impl PpAnn for NoAnn {}
  56
  57 #[derive(Copy, Clone)]
  58 pub struct CurrentCommentAndLiteral {
  59     pub cur_cmnt: usize,
  60     pub cur_lit: usize,
  61 }
  62
  63 pub struct State<'a> {
  64     pub s: pp::Printer<'a>,
  65     cm: Option<&'a CodeMap>,
  66     comments: Option<Vec<comments::Comment> >,
  67     literals: Option<Vec<comments::Literal> >,
  68     cur_cmnt_and_lit: CurrentCommentAndLiteral,
  69     boxes: Vec<pp::Breaks>,
  70     ann: &'a (PpAnn+'a),
  71 }
  72
  73 pub fn rust_printer<'a>(writer: Box<Write+'a>) -> State<'a> {
  74     static NO_ANN: NoAnn = NoAnn;
  75     rust_printer_annotated(writer, &NO_ANN)
  76 }
  77
  78 pub fn rust_printer_annotated<'a>(writer: Box<Write+'a>,
  79                                   ann: &'a PpAnn) -> State<'a> {
  80     State {
  81         s: pp::mk_printer(writer, DEFAULT_COLUMNS),
  82         cm: None,
  83         comments: None,
  84         literals: None,
  85         cur_cmnt_and_lit: CurrentCommentAndLiteral {
  86             cur_cmnt: 0,
  87             cur_lit: 0
  88         },
  89         boxes: Vec::new(),
  90         ann: ann,
  91     }
  92 }
  93
  94 pub const INDENT_UNIT: usize = 4;
  95
  96 pub const DEFAULT_COLUMNS: usize = 78;
  97
  98 /// Requires you to pass an input filename and reader so that
  99 /// it can scan the input text for comments and literals to
 100 /// copy forward.
 101 pub fn print_crate<'a>(cm: &'a CodeMap,
 102                        sess: &ParseSess,
 103                        krate: &ast::Crate,
 104                        filename: String,
 105                        input: &mut Read,
 106                        out: Box<Write+'a>,
 107                        ann: &'a PpAnn,
 108                        is_expanded: bool) -> io::Result<()> {
 109     let mut s = State::new_from_input(cm, sess, filename, input, out, ann, is_expanded);
 110
 111     if is_expanded && !std_inject::injected_crate_name(krate).is_none() {
 112         // We need to print `#![no_std]` (and its feature gate) so that
 113         // compiling pretty-printed source won't inject libstd again.
 114         // However we don't want these attributes in the AST because
 115         // of the feature gate, so we fake them up here.
 116
 117         // #![feature(prelude_import)]
 118         let prelude_import_meta = attr::mk_list_word_item(Symbol::intern("prelude_import"));
 119         let list = attr::mk_list_item(Symbol::intern("feature"), vec![prelude_import_meta]);
 120         let fake_attr = attr::mk_attr_inner(DUMMY_SP, attr::mk_attr_id(), list);
 121         s.print_attribute(&fake_attr)?;
 122
 123         // #![no_std]
 124         let no_std_meta = attr::mk_word_item(Symbol::intern("no_std"));
 125         let fake_attr = attr::mk_attr_inner(DUMMY_SP, attr::mk_attr_id(), no_std_meta);
 126         s.print_attribute(&fake_attr)?;
 127     }
 128
 129     s.print_mod(&krate.module, &krate.attrs)?;
 130     s.print_remaining_comments()?;
 131     eof(&mut s.s)
 132 }
 133
 134 impl<'a> State<'a> {
 135     pub fn new_from_input(cm: &'a CodeMap,
 136                           sess: &ParseSess,
 137                           filename: String,
 138                           input: &mut Read,
 139                           out: Box<Write+'a>,
 140                           ann: &'a PpAnn,
 141                           is_expanded: bool) -> State<'a> {
 142         let (cmnts, lits) = comments::gather_comments_and_literals(sess, filename, input);
 143
 144         State::new(
 145             cm,
 146             out,
 147             ann,
 148             Some(cmnts),
 149             // If the code is post expansion, don't use the table of
 150             // literals, since it doesn't correspond with the literals
 151             // in the AST anymore.
 152             if is_expanded { None } else { Some(lits) })
 153     }
 154
 155     pub fn new(cm: &'a CodeMap,
 156                out: Box<Write+'a>,
 157                ann: &'a PpAnn,
 158                comments: Option<Vec<comments::Comment>>,
 159                literals: Option<Vec<comments::Literal>>) -> State<'a> {
 160         State {
 161             s: pp::mk_printer(out, DEFAULT_COLUMNS),
 162             cm: Some(cm),
 163             comments: comments,
 164             literals: literals,
 165             cur_cmnt_and_lit: CurrentCommentAndLiteral {
 166                 cur_cmnt: 0,
 167                 cur_lit: 0
 168             },
 169             boxes: Vec::new(),
 170             ann: ann,
 171         }
 172     }
 173 }
 174
 175 pub fn to_string<F>(f: F) -> String where
 176     F: FnOnce(&mut State) -> io::Result<()>,
 177 {
 178     let mut wr = Vec::new();
 179     {
 180         let mut printer = rust_printer(Box::new(&mut wr));
 181         f(&mut printer).unwrap();
 182         eof(&mut printer.s).unwrap();
 183     }
 184     String::from_utf8(wr).unwrap()
 185 }
 186
 187 pub fn binop_to_string(op: BinOpToken) -> &'static str {
 188     match op {
 189         token::Plus     => "+",
 190         token::Minus    => "-",
 191         token::Star     => "*",
 192         token::Slash    => "/",
 193         token::Percent  => "%",
 194         token::Caret    => "^",
 195         token::And      => "&",
 196         token::Or       => "|",
 197         token::Shl      => "<<",
 198         token::Shr      => ">>",
 199     }
 200 }
 201
 202 pub fn token_to_string(tok: &Token) -> String {
 203     match *tok {
 204         token::Eq                   => "=".to_string(),
 205         token::Lt                   => "<".to_string(),
 206         token::Le                   => "<=".to_string(),
 207         token::EqEq                 => "==".to_string(),
 208         token::Ne                   => "!=".to_string(),
 209         token::Ge                   => ">=".to_string(),
 210         token::Gt                   => ">".to_string(),
 211         token::Not                  => "!".to_string(),
 212         token::Tilde                => "~".to_string(),
 213         token::OrOr                 => "||".to_string(),
 214         token::AndAnd               => "&&".to_string(),
 215         token::BinOp(op)            => binop_to_string(op).to_string(),
 216         token::BinOpEq(op)          => format!("{}=", binop_to_string(op)),
 217
 218         /* Structural symbols */
 219         token::At                   => "@".to_string(),
 220         token::Dot                  => ".".to_string(),
 221         token::DotDot               => "..".to_string(),
 222         token::DotDotDot            => "...".to_string(),
 223         token::Comma                => ",".to_string(),
 224         token::Semi                 => ";".to_string(),
 225         token::Colon                => ":".to_string(),
 226         token::ModSep               => "::".to_string(),
 227         token::RArrow               => "->".to_string(),
 228         token::LArrow               => "<-".to_string(),
 229         token::FatArrow             => "=>".to_string(),
 230         token::OpenDelim(token::Paren) => "(".to_string(),
 231         token::CloseDelim(token::Paren) => ")".to_string(),
 232         token::OpenDelim(token::Bracket) => "[".to_string(),
 233         token::CloseDelim(token::Bracket) => "]".to_string(),
 234         token::OpenDelim(token::Brace) => "{".to_string(),
 235         token::CloseDelim(token::Brace) => "}".to_string(),
 236         token::OpenDelim(token::NoDelim) => " ".to_string(),
 237         token::CloseDelim(token::NoDelim) => " ".to_string(),
 238         token::Pound                => "#".to_string(),
 239         token::Dollar               => "$".to_string(),
 240         token::Question             => "?".to_string(),
 241
 242         /* Literals */
 243         token::Literal(lit, suf) => {
 244             let mut out = match lit {
 245                 token::Byte(b)           => format!("b'{}'", b),
 246                 token::Char(c)           => format!("'{}'", c),
 247                 token::Float(c)          => c.to_string(),
 248                 token::Integer(c)        => c.to_string(),
 249                 token::Str_(s)           => format!("\"{}\"", s),
 250                 token::StrRaw(s, n)      => format!("r{delim}\"{string}\"{delim}",
 251                                                     delim=repeat("#", n),
 252                                                     string=s),
 253                 token::ByteStr(v)         => format!("b\"{}\"", v),
 254                 token::ByteStrRaw(s, n)   => format!("br{delim}\"{string}\"{delim}",
 255                                                     delim=repeat("#", n),
 256                                                     string=s),
 257             };
 258
 259             if let Some(s) = suf {
 260                 out.push_str(&s.as_str())
 261             }
 262
 263             out
 264         }
 265
 266         /* Name components */
 267         token::Ident(s)             => s.to_string(),
 268         token::Lifetime(s)          => s.to_string(),
 269         token::Underscore           => "_".to_string(),
 270
 271         /* Other */
 272         token::DocComment(s)        => s.to_string(),
 273         token::SubstNt(s)           => format!("${}", s),
 274         token::Eof                  => "<eof>".to_string(),
 275         token::Whitespace           => " ".to_string(),
 276         token::Comment              => "/* */".to_string(),
 277         token::Shebang(s)           => format!("/* shebang: {}*/", s),
 278
 279         token::Interpolated(ref nt) => match **nt {
 280             token::NtExpr(ref e)        => expr_to_string(&e),
 281             token::NtMeta(ref e)        => meta_item_to_string(&e),
 282             token::NtTy(ref e)          => ty_to_string(&e),
 283             token::NtPath(ref e)        => path_to_string(&e),
 284             token::NtItem(ref e)        => item_to_string(&e),
 285             token::NtBlock(ref e)       => block_to_string(&e),
 286             token::NtStmt(ref e)        => stmt_to_string(&e),
 287             token::NtPat(ref e)         => pat_to_string(&e),
 288             token::NtIdent(ref e)       => ident_to_string(e.node),
 289             token::NtTT(ref tree)       => tt_to_string(tree.clone()),
 290             token::NtArm(ref e)         => arm_to_string(&e),
 291             token::NtImplItem(ref e)    => impl_item_to_string(&e),
 292             token::NtTraitItem(ref e)   => trait_item_to_string(&e),
 293             token::NtGenerics(ref e)    => generics_to_string(&e),
 294             token::NtWhereClause(ref e) => where_clause_to_string(&e),
 295             token::NtArg(ref e)         => arg_to_string(&e),
 296             token::NtVis(ref e)         => vis_to_string(&e),
 297         }
 298     }
 299 }
 300
 301 pub fn ty_to_string(ty: &ast::Ty) -> String {
 302     to_string(|s| s.print_type(ty))
 303 }
 304
 305 pub fn bounds_to_string(bounds: &[ast::TyParamBound]) -> String {
 306     to_string(|s| s.print_bounds("", bounds))
 307 }
 308
 309 pub fn pat_to_string(pat: &ast::Pat) -> String {
 310     to_string(|s| s.print_pat(pat))
 311 }
 312
 313 pub fn arm_to_string(arm: &ast::Arm) -> String {
 314     to_string(|s| s.print_arm(arm))
 315 }
 316
 317 pub fn expr_to_string(e: &ast::Expr) -> String {
 318     to_string(|s| s.print_expr(e))
 319 }
 320
 321 pub fn lifetime_to_string(e: &ast::Lifetime) -> String {
 322     to_string(|s| s.print_lifetime(e))
 323 }
 324
 325 pub fn tt_to_string(tt: tokenstream::TokenTree) -> String {
 326     to_string(|s| s.print_tt(tt))
 327 }
 328
 329 pub fn tts_to_string(tts: &[tokenstream::TokenTree]) -> String {
 330     to_string(|s| s.print_tts(tts.iter().cloned().collect()))
 331 }
 332
 333 pub fn tokens_to_string(tokens: TokenStream) -> String {
 334     to_string(|s| s.print_tts(tokens))
 335 }
 336
 337 pub fn stmt_to_string(stmt: &ast::Stmt) -> String {
 338     to_string(|s| s.print_stmt(stmt))
 339 }
 340
 341 pub fn attr_to_string(attr: &ast::Attribute) -> String {
 342     to_string(|s| s.print_attribute(attr))
 343 }
 344
 345 pub fn item_to_string(i: &ast::Item) -> String {
 346     to_string(|s| s.print_item(i))
 347 }
 348
 349 pub fn impl_item_to_string(i: &ast::ImplItem) -> String {
 350     to_string(|s| s.print_impl_item(i))
 351 }
 352
 353 pub fn trait_item_to_string(i: &ast::TraitItem) -> String {
 354     to_string(|s| s.print_trait_item(i))
 355 }
 356
 357 pub fn generics_to_string(generics: &ast::Generics) -> String {
 358     to_string(|s| s.print_generics(generics))
 359 }
 360
 361 pub fn where_clause_to_string(i: &ast::WhereClause) -> String {
 362     to_string(|s| s.print_where_clause(i))
 363 }
 364
 365 pub fn fn_block_to_string(p: &ast::FnDecl) -> String {
 366     to_string(|s| s.print_fn_block_args(p))
 367 }
 368
 369 pub fn path_to_string(p: &ast::Path) -> String {
 370     to_string(|s| s.print_path(p, false, 0, false))
 371 }
 372
 373 pub fn ident_to_string(id: ast::Ident) -> String {
 374     to_string(|s| s.print_ident(id))
 375 }
 376
 377 pub fn vis_to_string(v: &ast::Visibility) -> String {
 378     to_string(|s| s.print_visibility(v))
 379 }
 380
 381 pub fn fun_to_string(decl: &ast::FnDecl,
 382                      unsafety: ast::Unsafety,
 383                      constness: ast::Constness,
 384                      name: ast::Ident,
 385                      generics: &ast::Generics)
 386                      -> String {
 387     to_string(|s| {
 388         s.head("")?;
 389         s.print_fn(decl, unsafety, constness, Abi::Rust, Some(name),
 390                    generics, &ast::Visibility::Inherited)?;
 391         s.end()?; // Close the head box
 392         s.end() // Close the outer box
 393     })
 394 }
 395
 396 pub fn block_to_string(blk: &ast::Block) -> String {
 397     to_string(|s| {
 398         // containing cbox, will be closed by print-block at }
 399         s.cbox(INDENT_UNIT)?;
 400         // head-ibox, will be closed by print-block after {
 401         s.ibox(0)?;
 402         s.print_block(blk)
 403     })
 404 }
 405
 406 pub fn meta_list_item_to_string(li: &ast::NestedMetaItem) -> String {
 407     to_string(|s| s.print_meta_list_item(li))
 408 }
 409
 410 pub fn meta_item_to_string(mi: &ast::MetaItem) -> String {
 411     to_string(|s| s.print_meta_item(mi))
 412 }
 413
 414 pub fn attribute_to_string(attr: &ast::Attribute) -> String {
 415     to_string(|s| s.print_attribute(attr))
 416 }
 417
 418 pub fn lit_to_string(l: &ast::Lit) -> String {
 419     to_string(|s| s.print_literal(l))
 420 }
 421
 422 pub fn variant_to_string(var: &ast::Variant) -> String {
 423     to_string(|s| s.print_variant(var))
 424 }
 425
 426 pub fn arg_to_string(arg: &ast::Arg) -> String {
 427     to_string(|s| s.print_arg(arg, false))
 428 }
 429
 430 pub fn mac_to_string(arg: &ast::Mac) -> String {
 431     to_string(|s| s.print_mac(arg, ::parse::token::Paren))
 432 }
 433
 434 pub fn visibility_qualified(vis: &ast::Visibility, s: &str) -> String {
 435     format!("{}{}", to_string(|s| s.print_visibility(vis)), s)
 436 }
 437
 438 fn needs_parentheses(expr: &ast::Expr) -> bool {
 439     match expr.node {
 440         ast::ExprKind::Assign(..) | ast::ExprKind::Binary(..) |
 441         ast::ExprKind::Closure(..) |
 442         ast::ExprKind::AssignOp(..) | ast::ExprKind::Cast(..) |
 443         ast::ExprKind::InPlace(..) | ast::ExprKind::Type(..) => true,
 444         _ => false,
 445     }
 446 }
 447
 448 pub trait PrintState<'a> {
 449     fn writer(&mut self) -> &mut pp::Printer<'a>;
 450     fn boxes(&mut self) -> &mut Vec<pp::Breaks>;
 451     fn comments(&mut self) -> &mut Option<Vec<comments::Comment>>;
 452     fn cur_cmnt_and_lit(&mut self) -> &mut CurrentCommentAndLiteral;
 453     fn literals(&self) -> &Option<Vec<comments::Literal>>;
 454
 455     fn word_space(&mut self, w: &str) -> io::Result<()> {
 456         word(self.writer(), w)?;
 457         space(self.writer())
 458     }
 459
 460     fn popen(&mut self) -> io::Result<()> { word(self.writer(), "(") }
 461
 462     fn pclose(&mut self) -> io::Result<()> { word(self.writer(), ")") }
 463
 464     fn is_begin(&mut self) -> bool {
 465         match self.writer().last_token() {
 466             pp::Token::Begin(_) => true,
 467             _ => false,
 468         }
 469     }
 470
 471     fn is_end(&mut self) -> bool {
 472         match self.writer().last_token() {
 473             pp::Token::End => true,
 474             _ => false,
 475         }
 476     }
 477
 478     // is this the beginning of a line?
 479     fn is_bol(&mut self) -> bool {
 480         self.writer().last_token().is_eof() || self.writer().last_token().is_hardbreak_tok()
 481     }
 482
 483     fn hardbreak_if_not_bol(&mut self) -> io::Result<()> {
 484         if !self.is_bol() {
 485             hardbreak(self.writer())?
 486         }
 487         Ok(())
 488     }
 489
 490     // "raw box"
 491     fn rbox(&mut self, u: usize, b: pp::Breaks) -> io::Result<()> {
 492         self.boxes().push(b);
 493         pp::rbox(self.writer(), u, b)
 494     }
 495
 496     fn ibox(&mut self, u: usize) -> io::Result<()> {
 497         self.boxes().push(pp::Breaks::Inconsistent);
 498         pp::ibox(self.writer(), u)
 499     }
 500
 501     fn end(&mut self) -> io::Result<()> {
 502         self.boxes().pop().unwrap();
 503         pp::end(self.writer())
 504     }
 505
 506     fn commasep<T, F>(&mut self, b: Breaks, elts: &[T], mut op: F) -> io::Result<()>
 507         where F: FnMut(&mut Self, &T) -> io::Result<()>,
 508     {
 509         self.rbox(0, b)?;
 510         let mut first = true;
 511         for elt in elts {
 512             if first { first = false; } else { self.word_space(",")?; }
 513             op(self, elt)?;
 514         }
 515         self.end()
 516     }
 517
 518     fn next_lit(&mut self, pos: BytePos) -> Option<comments::Literal> {
 519         let mut cur_lit = self.cur_cmnt_and_lit().cur_lit;
 520
 521         let mut result = None;
 522
 523         if let &Some(ref lits) = self.literals()
 524         {
 525             while cur_lit < lits.len() {
 526                 let ltrl = (*lits)[cur_lit].clone();
 527                 if ltrl.pos > pos { break; }
 528                 cur_lit += 1;
 529                 if ltrl.pos == pos {
 530                     result = Some(ltrl);
 531                     break;
 532                 }
 533             }
 534         }
 535
 536         self.cur_cmnt_and_lit().cur_lit = cur_lit;
 537         result
 538     }
 539
 540     fn maybe_print_comment(&mut self, pos: BytePos) -> io::Result<()> {
 541         while let Some(ref cmnt) = self.next_comment() {
 542             if cmnt.pos < pos {
 543                 self.print_comment(cmnt)?;
 544                 self.cur_cmnt_and_lit().cur_cmnt += 1;
 545             } else {
 546                 break
 547             }
 548         }
 549         Ok(())
 550     }
 551
 552     fn print_comment(&mut self,
 553                      cmnt: &comments::Comment) -> io::Result<()> {
 554         match cmnt.style {
 555             comments::Mixed => {
 556                 assert_eq!(cmnt.lines.len(), 1);
 557                 zerobreak(self.writer())?;
 558                 word(self.writer(), &cmnt.lines[0])?;
 559                 zerobreak(self.writer())
 560             }
 561             comments::Isolated => {
 562                 self.hardbreak_if_not_bol()?;
 563                 for line in &cmnt.lines {
 564                     // Don't print empty lines because they will end up as trailing
 565                     // whitespace
 566                     if !line.is_empty() {
 567                         word(self.writer(), &line[..])?;
 568                     }
 569                     hardbreak(self.writer())?;
 570                 }
 571                 Ok(())
 572             }
 573             comments::Trailing => {
 574                 if !self.is_bol() {
 575                     word(self.writer(), " ")?;
 576                 }
 577                 if cmnt.lines.len() == 1 {
 578                     word(self.writer(), &cmnt.lines[0])?;
 579                     hardbreak(self.writer())
 580                 } else {
 581                     self.ibox(0)?;
 582                     for line in &cmnt.lines {
 583                         if !line.is_empty() {
 584                             word(self.writer(), &line[..])?;
 585                         }
 586                         hardbreak(self.writer())?;
 587                     }
 588                     self.end()
 589                 }
 590             }
 591             comments::BlankLine => {
 592                 // We need to do at least one, possibly two hardbreaks.
 593                 let is_semi = match self.writer().last_token() {
 594                     pp::Token::String(s, _) => ";" == s,
 595                     _ => false
 596                 };
 597                 if is_semi || self.is_begin() || self.is_end() {
 598                     hardbreak(self.writer())?;
 599                 }
 600                 hardbreak(self.writer())
 601             }
 602         }
 603     }
 604
 605     fn next_comment(&mut self) -> Option<comments::Comment> {
 606         let cur_cmnt = self.cur_cmnt_and_lit().cur_cmnt;
 607         match *self.comments() {
 608             Some(ref cmnts) => {
 609                 if cur_cmnt < cmnts.len() {
 610                     Some(cmnts[cur_cmnt].clone())
 611                 } else {
 612                     None
 613                 }
 614             }
 615             _ => None
 616         }
 617     }
 618
 619     fn print_literal(&mut self, lit: &ast::Lit) -> io::Result<()> {
 620         self.maybe_print_comment(lit.span.lo)?;
 621         match self.next_lit(lit.span.lo) {
 622             Some(ref ltrl) => {
 623                 return word(self.writer(), &(*ltrl).lit);
 624             }
 625             _ => ()
 626         }
 627         match lit.node {
 628             ast::LitKind::Str(st, style) => self.print_string(&st.as_str(), style),
 629             ast::LitKind::Byte(byte) => {
 630                 let mut res = String::from("b'");
 631                 res.extend(ascii::escape_default(byte).map(|c| c as char));
 632                 res.push('\'');
 633                 word(self.writer(), &res[..])
 634             }
 635             ast::LitKind::Char(ch) => {
 636                 let mut res = String::from("'");
 637                 res.extend(ch.escape_default());
 638                 res.push('\'');
 639                 word(self.writer(), &res[..])
 640             }
 641             ast::LitKind::Int(i, t) => {
 642                 match t {
 643                     ast::LitIntType::Signed(st) => {
 644                         word(self.writer(), &st.val_to_string(i as i128))
 645                     }
 646                     ast::LitIntType::Unsigned(ut) => {
 647                         word(self.writer(), &ut.val_to_string(i))
 648                     }
 649                     ast::LitIntType::Unsuffixed => {
 650                         word(self.writer(), &format!("{}", i))
 651                     }
 652                 }
 653             }
 654             ast::LitKind::Float(ref f, t) => {
 655                 word(self.writer(),
 656                      &format!(
 657                          "{}{}",
 658                          &f,
 659                          t.ty_to_string()))
 660             }
 661             ast::LitKind::FloatUnsuffixed(ref f) => word(self.writer(), &f.as_str()),
 662             ast::LitKind::Bool(val) => {
 663                 if val { word(self.writer(), "true") } else { word(self.writer(), "false") }
 664             }
 665             ast::LitKind::ByteStr(ref v) => {
 666                 let mut escaped: String = String::new();
 667                 for &ch in v.iter() {
 668                     escaped.extend(ascii::escape_default(ch)
 669                                          .map(|c| c as char));
 670                 }
 671                 word(self.writer(), &format!("b\"{}\"", escaped))
 672             }
 673         }
 674     }
 675
 676     fn print_string(&mut self, st: &str,
 677                     style: ast::StrStyle) -> io::Result<()> {
 678         let st = match style {
 679             ast::StrStyle::Cooked => {
 680                 (format!("\"{}\"", st.escape_default()))
 681             }
 682             ast::StrStyle::Raw(n) => {
 683                 (format!("r{delim}\"{string}\"{delim}",
 684                          delim=repeat("#", n),
 685                          string=st))
 686             }
 687         };
 688         word(self.writer(), &st[..])
 689     }
 690
 691     fn print_inner_attributes(&mut self,
 692                               attrs: &[ast::Attribute]) -> io::Result<()> {
 693         self.print_either_attributes(attrs, ast::AttrStyle::Inner, false, true)
 694     }
 695
 696     fn print_inner_attributes_no_trailing_hardbreak(&mut self,
 697                                                    attrs: &[ast::Attribute])
 698                                                    -> io::Result<()> {
 699         self.print_either_attributes(attrs, ast::AttrStyle::Inner, false, false)
 700     }
 701
 702     fn print_outer_attributes(&mut self,
 703                               attrs: &[ast::Attribute]) -> io::Result<()> {
 704         self.print_either_attributes(attrs, ast::AttrStyle::Outer, false, true)
 705     }
 706
 707     fn print_inner_attributes_inline(&mut self,
 708                                      attrs: &[ast::Attribute]) -> io::Result<()> {
 709         self.print_either_attributes(attrs, ast::AttrStyle::Inner, true, true)
 710     }
 711
 712     fn print_outer_attributes_inline(&mut self,
 713                                      attrs: &[ast::Attribute]) -> io::Result<()> {
 714         self.print_either_attributes(attrs, ast::AttrStyle::Outer, true, true)
 715     }
 716
 717     fn print_either_attributes(&mut self,
 718                               attrs: &[ast::Attribute],
 719                               kind: ast::AttrStyle,
 720                               is_inline: bool,
 721                               trailing_hardbreak: bool) -> io::Result<()> {
 722         let mut count = 0;
 723         for attr in attrs {
 724             if attr.style == kind {
 725                 self.print_attribute_inline(attr, is_inline)?;
 726                 if is_inline {
 727                     self.nbsp()?;
 728                 }
 729                 count += 1;
 730             }
 731         }
 732         if count > 0 && trailing_hardbreak && !is_inline {
 733             self.hardbreak_if_not_bol()?;
 734         }
 735         Ok(())
 736     }
 737
 738     fn print_attribute(&mut self, attr: &ast::Attribute) -> io::Result<()> {
 739         self.print_attribute_inline(attr, false)
 740     }
 741
 742     fn print_attribute_inline(&mut self, attr: &ast::Attribute,
 743                               is_inline: bool) -> io::Result<()> {
 744         if !is_inline {
 745             self.hardbreak_if_not_bol()?;
 746         }
 747         self.maybe_print_comment(attr.span.lo)?;
 748         if attr.is_sugared_doc {
 749             word(self.writer(), &attr.value_str().unwrap().as_str())?;
 750             hardbreak(self.writer())
 751         } else {
 752             match attr.style {
 753                 ast::AttrStyle::Inner => word(self.writer(), "#![")?,
 754                 ast::AttrStyle::Outer => word(self.writer(), "#[")?,
 755             }
 756             if let Some(mi) = attr.meta() {
 757                 self.print_meta_item(&mi)?
 758             } else {
 759                 for (i, segment) in attr.path.segments.iter().enumerate() {
 760                     if i > 0 {
 761                         word(self.writer(), "::")?
 762                     }
 763                     if segment.identifier.name != keywords::CrateRoot.name() &&
 764                        segment.identifier.name != "$crate" {
 765                         word(self.writer(), &segment.identifier.name.as_str())?;
 766                     }
 767                 }
 768                 space(self.writer())?;
 769                 self.print_tts(attr.tokens.clone())?;
 770             }
 771             word(self.writer(), "]")
 772         }
 773     }
 774
 775     fn print_meta_list_item(&mut self, item: &ast::NestedMetaItem) -> io::Result<()> {
 776         match item.node {
 777             ast::NestedMetaItemKind::MetaItem(ref mi) => {
 778                 self.print_meta_item(mi)
 779             },
 780             ast::NestedMetaItemKind::Literal(ref lit) => {
 781                 self.print_literal(lit)
 782             }
 783         }
 784     }
 785
 786     fn print_meta_item(&mut self, item: &ast::MetaItem) -> io::Result<()> {
 787         self.ibox(INDENT_UNIT)?;
 788         match item.node {
 789             ast::MetaItemKind::Word => {
 790                 word(self.writer(), &item.name.as_str())?;
 791             }
 792             ast::MetaItemKind::NameValue(ref value) => {
 793                 self.word_space(&item.name.as_str())?;
 794                 self.word_space("=")?;
 795                 self.print_literal(value)?;
 796             }
 797             ast::MetaItemKind::List(ref items) => {
 798                 word(self.writer(), &item.name.as_str())?;
 799                 self.popen()?;
 800                 self.commasep(Consistent,
 801                               &items[..],
 802                               |s, i| s.print_meta_list_item(&i))?;
 803                 self.pclose()?;
 804             }
 805         }
 806         self.end()
 807     }
 808
 809     /// This doesn't deserve to be called "pretty" printing, but it should be
 810     /// meaning-preserving. A quick hack that might help would be to look at the
 811     /// spans embedded in the TTs to decide where to put spaces and newlines.
 812     /// But it'd be better to parse these according to the grammar of the
 813     /// appropriate macro, transcribe back into the grammar we just parsed from,
 814     /// and then pretty-print the resulting AST nodes (so, e.g., we print
 815     /// expression arguments as expressions). It can be done! I think.
 816     fn print_tt(&mut self, tt: tokenstream::TokenTree) -> io::Result<()> {
 817         match tt {
 818             TokenTree::Token(_, ref tk) => {
 819                 word(self.writer(), &token_to_string(tk))?;
 820                 match *tk {
 821                     parse::token::DocComment(..) => {
 822                         hardbreak(self.writer())
 823                     }
 824                     _ => Ok(())
 825                 }
 826             }
 827             TokenTree::Delimited(_, ref delimed) => {
 828                 word(self.writer(), &token_to_string(&delimed.open_token()))?;
 829                 space(self.writer())?;
 830                 self.print_tts(delimed.stream())?;
 831                 space(self.writer())?;
 832                 word(self.writer(), &token_to_string(&delimed.close_token()))
 833             },
 834         }
 835     }
 836
 837     fn print_tts(&mut self, tts: tokenstream::TokenStream) -> io::Result<()> {
 838         self.ibox(0)?;
 839         for (i, tt) in tts.into_trees().enumerate() {
 840             if i != 0 {
 841                 space(self.writer())?;
 842             }
 843             self.print_tt(tt)?;
 844         }
 845         self.end()
 846     }
 847
 848     fn space_if_not_bol(&mut self) -> io::Result<()> {
 849         if !self.is_bol() { space(self.writer())?; }
 850         Ok(())
 851     }
 852
 853     fn nbsp(&mut self) -> io::Result<()> { word(self.writer(), " ") }
 854 }
 855
 856 impl<'a> PrintState<'a> for State<'a> {
 857     fn writer(&mut self) -> &mut pp::Printer<'a> {
 858         &mut self.s
 859     }
 860
 861     fn boxes(&mut self) -> &mut Vec<pp::Breaks> {
 862         &mut self.boxes
 863     }
 864
 865     fn comments(&mut self) -> &mut Option<Vec<comments::Comment>> {
 866         &mut self.comments
 867     }
 868
 869     fn cur_cmnt_and_lit(&mut self) -> &mut CurrentCommentAndLiteral {
 870         &mut self.cur_cmnt_and_lit
 871     }
 872
 873     fn literals(&self) -> &Option<Vec<comments::Literal>> {
 874         &self.literals
 875     }
 876 }
 877
 878 impl<'a> State<'a> {
 879     pub fn cbox(&mut self, u: usize) -> io::Result<()> {
 880         self.boxes.push(pp::Breaks::Consistent);
 881         pp::cbox(&mut self.s, u)
 882     }
 883
 884     pub fn word_nbsp(&mut self, w: &str) -> io::Result<()> {
 885         word(&mut self.s, w)?;
 886         self.nbsp()
 887     }
 888
 889     pub fn head(&mut self, w: &str) -> io::Result<()> {
 890         // outer-box is consistent
 891         self.cbox(INDENT_UNIT)?;
 892         // head-box is inconsistent
 893         self.ibox(w.len() + 1)?;
 894         // keyword that starts the head
 895         if !w.is_empty() {
 896             self.word_nbsp(w)?;
 897         }
 898         Ok(())
 899     }
 900
 901     pub fn bopen(&mut self) -> io::Result<()> {
 902         word(&mut self.s, "{")?;
 903         self.end() // close the head-box
 904     }
 905
 906     pub fn bclose_(&mut self, span: syntax_pos::Span,
 907                    indented: usize) -> io::Result<()> {
 908         self.bclose_maybe_open(span, indented, true)
 909     }
 910     pub fn bclose_maybe_open(&mut self, span: syntax_pos::Span,
 911                              indented: usize, close_box: bool) -> io::Result<()> {
 912         self.maybe_print_comment(span.hi)?;
 913         self.break_offset_if_not_bol(1, -(indented as isize))?;
 914         word(&mut self.s, "}")?;
 915         if close_box {
 916             self.end()?; // close the outer-box
 917         }
 918         Ok(())
 919     }
 920     pub fn bclose(&mut self, span: syntax_pos::Span) -> io::Result<()> {
 921         self.bclose_(span, INDENT_UNIT)
 922     }
 923
 924     pub fn in_cbox(&self) -> bool {
 925         match self.boxes.last() {
 926             Some(&last_box) => last_box == pp::Breaks::Consistent,
 927             None => false
 928         }
 929     }
 930
 931     pub fn break_offset_if_not_bol(&mut self, n: usize,
 932                                    off: isize) -> io::Result<()> {
 933         if !self.is_bol() {
 934             break_offset(&mut self.s, n, off)
 935         } else {
 936             if off != 0 && self.s.last_token().is_hardbreak_tok() {
 937                 // We do something pretty sketchy here: tuck the nonzero
 938                 // offset-adjustment we were going to deposit along with the
 939                 // break into the previous hardbreak.
 940                 self.s.replace_last_token(pp::hardbreak_tok_offset(off));
 941             }
 942             Ok(())
 943         }
 944     }
 945
 946     // Synthesizes a comment that was not textually present in the original source
 947     // file.
 948     pub fn synth_comment(&mut self, text: String) -> io::Result<()> {
 949         word(&mut self.s, "/*")?;
 950         space(&mut self.s)?;
 951         word(&mut self.s, &text[..])?;
 952         space(&mut self.s)?;
 953         word(&mut self.s, "*/")
 954     }
 955
 956
 957
 958     pub fn commasep_cmnt<T, F, G>(&mut self,
 959                                   b: Breaks,
 960                                   elts: &[T],
 961                                   mut op: F,
 962                                   mut get_span: G) -> io::Result<()> where
 963         F: FnMut(&mut State, &T) -> io::Result<()>,
 964         G: FnMut(&T) -> syntax_pos::Span,
 965     {
 966         self.rbox(0, b)?;
 967         let len = elts.len();
 968         let mut i = 0;
 969         for elt in elts {
 970             self.maybe_print_comment(get_span(elt).hi)?;
 971             op(self, elt)?;
 972             i += 1;
 973             if i < len {
 974                 word(&mut self.s, ",")?;
 975                 self.maybe_print_trailing_comment(get_span(elt),
 976                                                   Some(get_span(&elts[i]).hi))?;
 977                 self.space_if_not_bol()?;
 978             }
 979         }
 980         self.end()
 981     }
 982
 983     pub fn commasep_exprs(&mut self, b: Breaks,
 984                           exprs: &[P<ast::Expr>]) -> io::Result<()> {
 985         self.commasep_cmnt(b, exprs, |s, e| s.print_expr(&e), |e| e.span)
 986     }
 987
 988     pub fn print_mod(&mut self, _mod: &ast::Mod,
 989                      attrs: &[ast::Attribute]) -> io::Result<()> {
 990         self.print_inner_attributes(attrs)?;
 991         for item in &_mod.items {
 992             self.print_item(&item)?;
 993         }
 994         Ok(())
 995     }
 996
 997     pub fn print_foreign_mod(&mut self, nmod: &ast::ForeignMod,
 998                              attrs: &[ast::Attribute]) -> io::Result<()> {
 999         self.print_inner_attributes(attrs)?;
1000         for item in &nmod.items {
1001             self.print_foreign_item(item)?;
1002         }
1003         Ok(())
1004     }
1005
1006     pub fn print_opt_lifetime(&mut self,
1007                               lifetime: &Option<ast::Lifetime>) -> io::Result<()> {
1008         if let Some(l) = *lifetime {
1009             self.print_lifetime(&l)?;
1010             self.nbsp()?;
1011         }
1012         Ok(())
1013     }
1014
1015     pub fn print_type(&mut self, ty: &ast::Ty) -> io::Result<()> {
1016         self.maybe_print_comment(ty.span.lo)?;
1017         self.ibox(0)?;
1018         match ty.node {
1019             ast::TyKind::Slice(ref ty) => {
1020                 word(&mut self.s, "[")?;
1021                 self.print_type(&ty)?;
1022                 word(&mut self.s, "]")?;
1023             }
1024             ast::TyKind::Ptr(ref mt) => {
1025                 word(&mut self.s, "*")?;
1026                 match mt.mutbl {
1027                     ast::Mutability::Mutable => self.word_nbsp("mut")?,
1028                     ast::Mutability::Immutable => self.word_nbsp("const")?,
1029                 }
1030                 self.print_type(&mt.ty)?;
1031             }
1032             ast::TyKind::Rptr(ref lifetime, ref mt) => {
1033                 word(&mut self.s, "&")?;
1034                 self.print_opt_lifetime(lifetime)?;
1035                 self.print_mt(mt)?;
1036             }
1037             ast::TyKind::Never => {
1038                 word(&mut self.s, "!")?;
1039             },
1040             ast::TyKind::Tup(ref elts) => {
1041                 self.popen()?;
1042                 self.commasep(Inconsistent, &elts[..],
1043                               |s, ty| s.print_type(&ty))?;
1044                 if elts.len() == 1 {
1045                     word(&mut self.s, ",")?;
1046                 }
1047                 self.pclose()?;
1048             }
1049             ast::TyKind::Paren(ref typ) => {
1050                 self.popen()?;
1051                 self.print_type(&typ)?;
1052                 self.pclose()?;
1053             }
1054             ast::TyKind::BareFn(ref f) => {
1055                 let generics = ast::Generics {
1056                     lifetimes: f.lifetimes.clone(),
1057                     ty_params: Vec::new(),
1058                     where_clause: ast::WhereClause {
1059                         id: ast::DUMMY_NODE_ID,
1060                         predicates: Vec::new(),
1061                     },
1062                     span: syntax_pos::DUMMY_SP,
1063                 };
1064                 self.print_ty_fn(f.abi,
1065                                  f.unsafety,
1066                                  &f.decl,
1067                                  None,
1068                                  &generics)?;
1069             }
1070             ast::TyKind::Path(None, ref path) => {
1071                 self.print_path(path, false, 0, false)?;
1072             }
1073             ast::TyKind::Path(Some(ref qself), ref path) => {
1074                 self.print_qpath(path, qself, false)?
1075             }
1076             ast::TyKind::TraitObject(ref bounds) => {
1077                 self.print_bounds("", &bounds[..])?;
1078             }
1079             ast::TyKind::ImplTrait(ref bounds) => {
1080                 self.print_bounds("impl ", &bounds[..])?;
1081             }
1082             ast::TyKind::Array(ref ty, ref v) => {
1083                 word(&mut self.s, "[")?;
1084                 self.print_type(&ty)?;
1085                 word(&mut self.s, "; ")?;
1086                 self.print_expr(&v)?;
1087                 word(&mut self.s, "]")?;
1088             }
1089             ast::TyKind::Typeof(ref e) => {
1090                 word(&mut self.s, "typeof(")?;
1091                 self.print_expr(&e)?;
1092                 word(&mut self.s, ")")?;
1093             }
1094             ast::TyKind::Infer => {
1095                 word(&mut self.s, "_")?;
1096             }
1097             ast::TyKind::Err => {
1098                 word(&mut self.s, "?")?;
1099             }
1100             ast::TyKind::ImplicitSelf => {
1101                 word(&mut self.s, "Self")?;
1102             }
1103             ast::TyKind::Mac(ref m) => {
1104                 self.print_mac(m, token::Paren)?;
1105             }
1106         }
1107         self.end()
1108     }
1109
1110     pub fn print_foreign_item(&mut self,
1111                               item: &ast::ForeignItem) -> io::Result<()> {
1112         self.hardbreak_if_not_bol()?;
1113         self.maybe_print_comment(item.span.lo)?;
1114         self.print_outer_attributes(&item.attrs)?;
1115         match item.node {
1116             ast::ForeignItemKind::Fn(ref decl, ref generics) => {
1117                 self.head("")?;
1118                 self.print_fn(decl, ast::Unsafety::Normal,
1119                               ast::Constness::NotConst,
1120                               Abi::Rust, Some(item.ident),
1121                               generics, &item.vis)?;
1122                 self.end()?; // end head-ibox
1123                 word(&mut self.s, ";")?;
1124                 self.end() // end the outer fn box
1125             }
1126             ast::ForeignItemKind::Static(ref t, m) => {
1127                 self.head(&visibility_qualified(&item.vis, "static"))?;
1128                 if m {
1129                     self.word_space("mut")?;
1130                 }
1131                 self.print_ident(item.ident)?;
1132                 self.word_space(":")?;
1133                 self.print_type(&t)?;
1134                 word(&mut self.s, ";")?;
1135                 self.end()?; // end the head-ibox
1136                 self.end() // end the outer cbox
1137             }
1138         }
1139     }
1140
1141     fn print_associated_const(&mut self,
1142                               ident: ast::Ident,
1143                               ty: &ast::Ty,
1144                               default: Option<&ast::Expr>,
1145                               vis: &ast::Visibility)
1146                               -> io::Result<()>
1147     {
1148         word(&mut self.s, &visibility_qualified(vis, ""))?;
1149         self.word_space("const")?;
1150         self.print_ident(ident)?;
1151         self.word_space(":")?;
1152         self.print_type(ty)?;
1153         if let Some(expr) = default {
1154             space(&mut self.s)?;
1155             self.word_space("=")?;
1156             self.print_expr(expr)?;
1157         }
1158         word(&mut self.s, ";")
1159     }
1160
1161     fn print_associated_type(&mut self,
1162                              ident: ast::Ident,
1163                              bounds: Option<&ast::TyParamBounds>,
1164                              ty: Option<&ast::Ty>)
1165                              -> io::Result<()> {
1166         self.word_space("type")?;
1167         self.print_ident(ident)?;
1168         if let Some(bounds) = bounds {
1169             self.print_bounds(":", bounds)?;
1170         }
1171         if let Some(ty) = ty {
1172             space(&mut self.s)?;
1173             self.word_space("=")?;
1174             self.print_type(ty)?;
1175         }
1176         word(&mut self.s, ";")
1177     }
1178
1179     /// Pretty-print an item
1180     pub fn print_item(&mut self, item: &ast::Item) -> io::Result<()> {
1181         self.hardbreak_if_not_bol()?;
1182         self.maybe_print_comment(item.span.lo)?;
1183         self.print_outer_attributes(&item.attrs)?;
1184         self.ann.pre(self, NodeItem(item))?;
1185         match item.node {
1186             ast::ItemKind::ExternCrate(ref optional_path) => {
1187                 self.head(&visibility_qualified(&item.vis, "extern crate"))?;
1188                 if let Some(p) = *optional_path {
1189                     let val = p.as_str();
1190                     if val.contains("-") {
1191                         self.print_string(&val, ast::StrStyle::Cooked)?;
1192                     } else {
1193                         self.print_name(p)?;
1194                     }
1195                     space(&mut self.s)?;
1196                     word(&mut self.s, "as")?;
1197                     space(&mut self.s)?;
1198                 }
1199                 self.print_ident(item.ident)?;
1200                 word(&mut self.s, ";")?;
1201                 self.end()?; // end inner head-block
1202                 self.end()?; // end outer head-block
1203             }
1204             ast::ItemKind::Use(ref vp) => {
1205                 self.head(&visibility_qualified(&item.vis, "use"))?;
1206                 self.print_view_path(&vp)?;
1207                 word(&mut self.s, ";")?;
1208                 self.end()?; // end inner head-block
1209                 self.end()?; // end outer head-block
1210             }
1211             ast::ItemKind::Static(ref ty, m, ref expr) => {
1212                 self.head(&visibility_qualified(&item.vis, "static"))?;
1213                 if m == ast::Mutability::Mutable {
1214                     self.word_space("mut")?;
1215                 }
1216                 self.print_ident(item.ident)?;
1217                 self.word_space(":")?;
1218                 self.print_type(&ty)?;
1219                 space(&mut self.s)?;
1220                 self.end()?; // end the head-ibox
1221
1222                 self.word_space("=")?;
1223                 self.print_expr(&expr)?;
1224                 word(&mut self.s, ";")?;
1225                 self.end()?; // end the outer cbox
1226             }
1227             ast::ItemKind::Const(ref ty, ref expr) => {
1228                 self.head(&visibility_qualified(&item.vis, "const"))?;
1229                 self.print_ident(item.ident)?;
1230                 self.word_space(":")?;
1231                 self.print_type(&ty)?;
1232                 space(&mut self.s)?;
1233                 self.end()?; // end the head-ibox
1234
1235                 self.word_space("=")?;
1236                 self.print_expr(&expr)?;
1237                 word(&mut self.s, ";")?;
1238                 self.end()?; // end the outer cbox
1239             }
1240             ast::ItemKind::Fn(ref decl, unsafety, constness, abi, ref typarams, ref body) => {
1241                 self.head("")?;
1242                 self.print_fn(
1243                     decl,
1244                     unsafety,
1245                     constness.node,
1246                     abi,
1247                     Some(item.ident),
1248                     typarams,
1249                     &item.vis
1250                 )?;
1251                 word(&mut self.s, " ")?;
1252                 self.print_block_with_attrs(&body, &item.attrs)?;
1253             }
1254             ast::ItemKind::Mod(ref _mod) => {
1255                 self.head(&visibility_qualified(&item.vis, "mod"))?;
1256                 self.print_ident(item.ident)?;
1257                 self.nbsp()?;
1258                 self.bopen()?;
1259                 self.print_mod(_mod, &item.attrs)?;
1260                 self.bclose(item.span)?;
1261             }
1262             ast::ItemKind::ForeignMod(ref nmod) => {
1263                 self.head("extern")?;
1264                 self.word_nbsp(&nmod.abi.to_string())?;
1265                 self.bopen()?;
1266                 self.print_foreign_mod(nmod, &item.attrs)?;
1267                 self.bclose(item.span)?;
1268             }
1269             ast::ItemKind::GlobalAsm(ref ga) => {
1270                 self.head(&visibility_qualified(&item.vis, "global_asm!"))?;
1271                 word(&mut self.s, &ga.asm.as_str())?;
1272                 self.end()?;
1273             }
1274             ast::ItemKind::Ty(ref ty, ref params) => {
1275                 self.ibox(INDENT_UNIT)?;
1276                 self.ibox(0)?;
1277                 self.word_nbsp(&visibility_qualified(&item.vis, "type"))?;
1278                 self.print_ident(item.ident)?;
1279                 self.print_generics(params)?;
1280                 self.end()?; // end the inner ibox
1281
1282                 self.print_where_clause(&params.where_clause)?;
1283                 space(&mut self.s)?;
1284                 self.word_space("=")?;
1285                 self.print_type(&ty)?;
1286                 word(&mut self.s, ";")?;
1287                 self.end()?; // end the outer ibox
1288             }
1289             ast::ItemKind::Enum(ref enum_definition, ref params) => {
1290                 self.print_enum_def(
1291                     enum_definition,
1292                     params,
1293                     item.ident,
1294                     item.span,
1295                     &item.vis
1296                 )?;
1297             }
1298             ast::ItemKind::Struct(ref struct_def, ref generics) => {
1299                 self.head(&visibility_qualified(&item.vis, "struct"))?;
1300                 self.print_struct(&struct_def, generics, item.ident, item.span, true)?;
1301             }
1302             ast::ItemKind::Union(ref struct_def, ref generics) => {
1303                 self.head(&visibility_qualified(&item.vis, "union"))?;
1304                 self.print_struct(&struct_def, generics, item.ident, item.span, true)?;
1305             }
1306             ast::ItemKind::DefaultImpl(unsafety, ref trait_ref) => {
1307                 self.head("")?;
1308                 self.print_visibility(&item.vis)?;
1309                 self.print_unsafety(unsafety)?;
1310                 self.word_nbsp("impl")?;
1311                 self.print_trait_ref(trait_ref)?;
1312                 space(&mut self.s)?;
1313                 self.word_space("for")?;
1314                 self.word_space("..")?;
1315                 self.bopen()?;
1316                 self.bclose(item.span)?;
1317             }
1318             ast::ItemKind::Impl(unsafety,
1319                           polarity,
1320                           ref generics,
1321                           ref opt_trait,
1322                           ref ty,
1323                           ref impl_items) => {
1324                 self.head("")?;
1325                 self.print_visibility(&item.vis)?;
1326                 self.print_unsafety(unsafety)?;
1327                 self.word_nbsp("impl")?;
1328
1329                 if generics.is_parameterized() {
1330                     self.print_generics(generics)?;
1331                     space(&mut self.s)?;
1332                 }
1333
1334                 match polarity {
1335                     ast::ImplPolarity::Negative => {
1336                         word(&mut self.s, "!")?;
1337                     },
1338                     _ => {}
1339                 }
1340
1341                 if let Some(ref t) = *opt_trait {
1342                     self.print_trait_ref(t)?;
1343                     space(&mut self.s)?;
1344                     self.word_space("for")?;
1345                 }
1346
1347                 self.print_type(&ty)?;
1348                 self.print_where_clause(&generics.where_clause)?;
1349
1350                 space(&mut self.s)?;
1351                 self.bopen()?;
1352                 self.print_inner_attributes(&item.attrs)?;
1353                 for impl_item in impl_items {
1354                     self.print_impl_item(impl_item)?;
1355                 }
1356                 self.bclose(item.span)?;
1357             }
1358             ast::ItemKind::Trait(unsafety, ref generics, ref bounds, ref trait_items) => {
1359                 self.head("")?;
1360                 self.print_visibility(&item.vis)?;
1361                 self.print_unsafety(unsafety)?;
1362                 self.word_nbsp("trait")?;
1363                 self.print_ident(item.ident)?;
1364                 self.print_generics(generics)?;
1365                 let mut real_bounds = Vec::with_capacity(bounds.len());
1366                 for b in bounds.iter() {
1367                     if let TraitTyParamBound(ref ptr, ast::TraitBoundModifier::Maybe) = *b {
1368                         space(&mut self.s)?;
1369                         self.word_space("for ?")?;
1370                         self.print_trait_ref(&ptr.trait_ref)?;
1371                     } else {
1372                         real_bounds.push(b.clone());
1373                     }
1374                 }
1375                 self.print_bounds(":", &real_bounds[..])?;
1376                 self.print_where_clause(&generics.where_clause)?;
1377                 word(&mut self.s, " ")?;
1378                 self.bopen()?;
1379                 for trait_item in trait_items {
1380                     self.print_trait_item(trait_item)?;
1381                 }
1382                 self.bclose(item.span)?;
1383             }
1384             ast::ItemKind::Mac(codemap::Spanned { ref node, .. }) => {
1385                 self.print_path(&node.path, false, 0, false)?;
1386                 word(&mut self.s, "! ")?;
1387                 self.print_ident(item.ident)?;
1388                 self.cbox(INDENT_UNIT)?;
1389                 self.popen()?;
1390                 self.print_tts(node.stream())?;
1391                 self.pclose()?;
1392                 word(&mut self.s, ";")?;
1393                 self.end()?;
1394             }
1395             ast::ItemKind::MacroDef(ref tts) => {
1396                 word(&mut self.s, "macro_rules! ")?;
1397                 self.print_ident(item.ident)?;
1398                 self.cbox(INDENT_UNIT)?;
1399                 self.popen()?;
1400                 self.print_tts(tts.clone().into())?;
1401                 self.pclose()?;
1402                 word(&mut self.s, ";")?;
1403                 self.end()?;
1404             }
1405         }
1406         self.ann.post(self, NodeItem(item))
1407     }
1408
1409     fn print_trait_ref(&mut self, t: &ast::TraitRef) -> io::Result<()> {
1410         self.print_path(&t.path, false, 0, false)
1411     }
1412
1413     fn print_formal_lifetime_list(&mut self, lifetimes: &[ast::LifetimeDef]) -> io::Result<()> {
1414         if !lifetimes.is_empty() {
1415             word(&mut self.s, "for<")?;
1416             let mut comma = false;
1417             for lifetime_def in lifetimes {
1418                 if comma {
1419                     self.word_space(",")?
1420                 }
1421                 self.print_outer_attributes_inline(&lifetime_def.attrs)?;
1422                 self.print_lifetime_bounds(&lifetime_def.lifetime, &lifetime_def.bounds)?;
1423                 comma = true;
1424             }
1425             word(&mut self.s, ">")?;
1426         }
1427         Ok(())
1428     }
1429
1430     fn print_poly_trait_ref(&mut self, t: &ast::PolyTraitRef) -> io::Result<()> {
1431         self.print_formal_lifetime_list(&t.bound_lifetimes)?;
1432         self.print_trait_ref(&t.trait_ref)
1433     }
1434
1435     pub fn print_enum_def(&mut self, enum_definition: &ast::EnumDef,
1436                           generics: &ast::Generics, ident: ast::Ident,
1437                           span: syntax_pos::Span,
1438                           visibility: &ast::Visibility) -> io::Result<()> {
1439         self.head(&visibility_qualified(visibility, "enum"))?;
1440         self.print_ident(ident)?;
1441         self.print_generics(generics)?;
1442         self.print_where_clause(&generics.where_clause)?;
1443         space(&mut self.s)?;
1444         self.print_variants(&enum_definition.variants, span)
1445     }
1446
1447     pub fn print_variants(&mut self,
1448                           variants: &[ast::Variant],
1449                           span: syntax_pos::Span) -> io::Result<()> {
1450         self.bopen()?;
1451         for v in variants {
1452             self.space_if_not_bol()?;
1453             self.maybe_print_comment(v.span.lo)?;
1454             self.print_outer_attributes(&v.node.attrs)?;
1455             self.ibox(INDENT_UNIT)?;
1456             self.print_variant(v)?;
1457             word(&mut self.s, ",")?;
1458             self.end()?;
1459             self.maybe_print_trailing_comment(v.span, None)?;
1460         }
1461         self.bclose(span)
1462     }
1463
1464     pub fn print_visibility(&mut self, vis: &ast::Visibility) -> io::Result<()> {
1465         match *vis {
1466             ast::Visibility::Public => self.word_nbsp("pub"),
1467             ast::Visibility::Crate(_) => self.word_nbsp("pub(crate)"),
1468             ast::Visibility::Restricted { ref path, .. } => {
1469                 let path = to_string(|s| s.print_path(path, false, 0, true));
1470                 if path == "self" || path == "super" {
1471                     self.word_nbsp(&format!("pub({})", path))
1472                 } else {
1473                     self.word_nbsp(&format!("pub(in {})", path))
1474                 }
1475             }
1476             ast::Visibility::Inherited => Ok(())
1477         }
1478     }
1479
1480     pub fn print_struct(&mut self,
1481                         struct_def: &ast::VariantData,
1482                         generics: &ast::Generics,
1483                         ident: ast::Ident,
1484                         span: syntax_pos::Span,
1485                         print_finalizer: bool) -> io::Result<()> {
1486         self.print_ident(ident)?;
1487         self.print_generics(generics)?;
1488         if !struct_def.is_struct() {
1489             if struct_def.is_tuple() {
1490                 self.popen()?;
1491                 self.commasep(
1492                     Inconsistent, struct_def.fields(),
1493                     |s, field| {
1494                         s.maybe_print_comment(field.span.lo)?;
1495                         s.print_outer_attributes(&field.attrs)?;
1496                         s.print_visibility(&field.vis)?;
1497                         s.print_type(&field.ty)
1498                     }
1499                 )?;
1500                 self.pclose()?;
1501             }
1502             self.print_where_clause(&generics.where_clause)?;
1503             if print_finalizer {
1504                 word(&mut self.s, ";")?;
1505             }
1506             self.end()?;
1507             self.end() // close the outer-box
1508         } else {
1509             self.print_where_clause(&generics.where_clause)?;
1510             self.nbsp()?;
1511             self.bopen()?;
1512             self.hardbreak_if_not_bol()?;
1513
1514             for field in struct_def.fields() {
1515                 self.hardbreak_if_not_bol()?;
1516                 self.maybe_print_comment(field.span.lo)?;
1517                 self.print_outer_attributes(&field.attrs)?;
1518                 self.print_visibility(&field.vis)?;
1519                 self.print_ident(field.ident.unwrap())?;
1520                 self.word_nbsp(":")?;
1521                 self.print_type(&field.ty)?;
1522                 word(&mut self.s, ",")?;
1523             }
1524
1525             self.bclose(span)
1526         }
1527     }
1528
1529     pub fn print_variant(&mut self, v: &ast::Variant) -> io::Result<()> {
1530         self.head("")?;
1531         let generics = ast::Generics::default();
1532         self.print_struct(&v.node.data, &generics, v.node.name, v.span, false)?;
1533         match v.node.disr_expr {
1534             Some(ref d) => {
1535                 space(&mut self.s)?;
1536                 self.word_space("=")?;
1537                 self.print_expr(&d)
1538             }
1539             _ => Ok(())
1540         }
1541     }
1542
1543     pub fn print_method_sig(&mut self,
1544                             ident: ast::Ident,
1545                             m: &ast::MethodSig,
1546                             vis: &ast::Visibility)
1547                             -> io::Result<()> {
1548         self.print_fn(&m.decl,
1549                       m.unsafety,
1550                       m.constness.node,
1551                       m.abi,
1552                       Some(ident),
1553                       &m.generics,
1554                       vis)
1555     }
1556
1557     pub fn print_trait_item(&mut self, ti: &ast::TraitItem)
1558                             -> io::Result<()> {
1559         self.ann.pre(self, NodeSubItem(ti.id))?;
1560         self.hardbreak_if_not_bol()?;
1561         self.maybe_print_comment(ti.span.lo)?;
1562         self.print_outer_attributes(&ti.attrs)?;
1563         match ti.node {
1564             ast::TraitItemKind::Const(ref ty, ref default) => {
1565                 self.print_associated_const(ti.ident, &ty,
1566                                             default.as_ref().map(|expr| &**expr),
1567                                             &ast::Visibility::Inherited)?;
1568             }
1569             ast::TraitItemKind::Method(ref sig, ref body) => {
1570                 if body.is_some() {
1571                     self.head("")?;
1572                 }
1573                 self.print_method_sig(ti.ident, sig, &ast::Visibility::Inherited)?;
1574                 if let Some(ref body) = *body {
1575                     self.nbsp()?;
1576                     self.print_block_with_attrs(body, &ti.attrs)?;
1577                 } else {
1578                     word(&mut self.s, ";")?;
1579                 }
1580             }
1581             ast::TraitItemKind::Type(ref bounds, ref default) => {
1582                 self.print_associated_type(ti.ident, Some(bounds),
1583                                            default.as_ref().map(|ty| &**ty))?;
1584             }
1585             ast::TraitItemKind::Macro(codemap::Spanned { ref node, .. }) => {
1586                 // code copied from ItemKind::Mac:
1587                 self.print_path(&node.path, false, 0, false)?;
1588                 word(&mut self.s, "! ")?;
1589                 self.cbox(INDENT_UNIT)?;
1590                 self.popen()?;
1591                 self.print_tts(node.stream())?;
1592                 self.pclose()?;
1593                 word(&mut self.s, ";")?;
1594                 self.end()?
1595             }
1596         }
1597         self.ann.post(self, NodeSubItem(ti.id))
1598     }
1599
1600     pub fn print_impl_item(&mut self, ii: &ast::ImplItem) -> io::Result<()> {
1601         self.ann.pre(self, NodeSubItem(ii.id))?;
1602         self.hardbreak_if_not_bol()?;
1603         self.maybe_print_comment(ii.span.lo)?;
1604         self.print_outer_attributes(&ii.attrs)?;
1605         if let ast::Defaultness::Default = ii.defaultness {
1606             self.word_nbsp("default")?;
1607         }
1608         match ii.node {
1609             ast::ImplItemKind::Const(ref ty, ref expr) => {
1610                 self.print_associated_const(ii.ident, &ty, Some(&expr), &ii.vis)?;
1611             }
1612             ast::ImplItemKind::Method(ref sig, ref body) => {
1613                 self.head("")?;
1614                 self.print_method_sig(ii.ident, sig, &ii.vis)?;
1615                 self.nbsp()?;
1616                 self.print_block_with_attrs(body, &ii.attrs)?;
1617             }
1618             ast::ImplItemKind::Type(ref ty) => {
1619                 self.print_associated_type(ii.ident, None, Some(ty))?;
1620             }
1621             ast::ImplItemKind::Macro(codemap::Spanned { ref node, .. }) => {
1622                 // code copied from ItemKind::Mac:
1623                 self.print_path(&node.path, false, 0, false)?;
1624                 word(&mut self.s, "! ")?;
1625                 self.cbox(INDENT_UNIT)?;
1626                 self.popen()?;
1627                 self.print_tts(node.stream())?;
1628                 self.pclose()?;
1629                 word(&mut self.s, ";")?;
1630                 self.end()?
1631             }
1632         }
1633         self.ann.post(self, NodeSubItem(ii.id))
1634     }
1635
1636     pub fn print_stmt(&mut self, st: &ast::Stmt) -> io::Result<()> {
1637         self.maybe_print_comment(st.span.lo)?;
1638         match st.node {
1639             ast::StmtKind::Local(ref loc) => {
1640                 self.print_outer_attributes(&loc.attrs)?;
1641                 self.space_if_not_bol()?;
1642                 self.ibox(INDENT_UNIT)?;
1643                 self.word_nbsp("let")?;
1644
1645                 self.ibox(INDENT_UNIT)?;
1646                 self.print_local_decl(&loc)?;
1647                 self.end()?;
1648                 if let Some(ref init) = loc.init {
1649                     self.nbsp()?;
1650                     self.word_space("=")?;
1651                     self.print_expr(&init)?;
1652                 }
1653                 word(&mut self.s, ";")?;
1654                 self.end()?;
1655             }
1656             ast::StmtKind::Item(ref item) => self.print_item(&item)?,
1657             ast::StmtKind::Expr(ref expr) => {
1658                 self.space_if_not_bol()?;
1659                 self.print_expr_outer_attr_style(&expr, false)?;
1660                 if parse::classify::expr_requires_semi_to_be_stmt(expr) {
1661                     word(&mut self.s, ";")?;
1662                 }
1663             }
1664             ast::StmtKind::Semi(ref expr) => {
1665                 self.space_if_not_bol()?;
1666                 self.print_expr_outer_attr_style(&expr, false)?;
1667                 word(&mut self.s, ";")?;
1668             }
1669             ast::StmtKind::Mac(ref mac) => {
1670                 let (ref mac, style, ref attrs) = **mac;
1671                 self.space_if_not_bol()?;
1672                 self.print_outer_attributes(&attrs)?;
1673                 let delim = match style {
1674                     ast::MacStmtStyle::Braces => token::Brace,
1675                     _ => token::Paren
1676                 };
1677                 self.print_mac(&mac, delim)?;
1678                 if style == ast::MacStmtStyle::Semicolon {
1679                     word(&mut self.s, ";")?;
1680                 }
1681             }
1682         }
1683         self.maybe_print_trailing_comment(st.span, None)
1684     }
1685
1686     pub fn print_block(&mut self, blk: &ast::Block) -> io::Result<()> {
1687         self.print_block_with_attrs(blk, &[])
1688     }
1689
1690     pub fn print_block_unclosed(&mut self, blk: &ast::Block) -> io::Result<()> {
1691         self.print_block_unclosed_indent(blk, INDENT_UNIT)
1692     }
1693
1694     pub fn print_block_unclosed_with_attrs(&mut self, blk: &ast::Block,
1695                                             attrs: &[ast::Attribute])
1696                                            -> io::Result<()> {
1697         self.print_block_maybe_unclosed(blk, INDENT_UNIT, attrs, false)
1698     }
1699
1700     pub fn print_block_unclosed_indent(&mut self, blk: &ast::Block,
1701                                        indented: usize) -> io::Result<()> {
1702         self.print_block_maybe_unclosed(blk, indented, &[], false)
1703     }
1704
1705     pub fn print_block_with_attrs(&mut self,
1706                                   blk: &ast::Block,
1707                                   attrs: &[ast::Attribute]) -> io::Result<()> {
1708         self.print_block_maybe_unclosed(blk, INDENT_UNIT, attrs, true)
1709     }
1710
1711     pub fn print_block_maybe_unclosed(&mut self,
1712                                       blk: &ast::Block,
1713                                       indented: usize,
1714                                       attrs: &[ast::Attribute],
1715                                       close_box: bool) -> io::Result<()> {
1716         match blk.rules {
1717             BlockCheckMode::Unsafe(..) => self.word_space("unsafe")?,
1718             BlockCheckMode::Default => ()
1719         }
1720         self.maybe_print_comment(blk.span.lo)?;
1721         self.ann.pre(self, NodeBlock(blk))?;
1722         self.bopen()?;
1723
1724         self.print_inner_attributes(attrs)?;
1725
1726         for (i, st) in blk.stmts.iter().enumerate() {
1727             match st.node {
1728                 ast::StmtKind::Expr(ref expr) if i == blk.stmts.len() - 1 => {
1729                     self.maybe_print_comment(st.span.lo)?;
1730                     self.space_if_not_bol()?;
1731                     self.print_expr_outer_attr_style(&expr, false)?;
1732                     self.maybe_print_trailing_comment(expr.span, Some(blk.span.hi))?;
1733                 }
1734                 _ => self.print_stmt(st)?,
1735             }
1736         }
1737
1738         self.bclose_maybe_open(blk.span, indented, close_box)?;
1739         self.ann.post(self, NodeBlock(blk))
1740     }
1741
1742     fn print_else(&mut self, els: Option<&ast::Expr>) -> io::Result<()> {
1743         match els {
1744             Some(_else) => {
1745                 match _else.node {
1746                     // "another else-if"
1747                     ast::ExprKind::If(ref i, ref then, ref e) => {
1748                         self.cbox(INDENT_UNIT - 1)?;
1749                         self.ibox(0)?;
1750                         word(&mut self.s, " else if ")?;
1751                         self.print_expr(&i)?;
1752                         space(&mut self.s)?;
1753                         self.print_block(&then)?;
1754                         self.print_else(e.as_ref().map(|e| &**e))
1755                     }
1756                     // "another else-if-let"
1757                     ast::ExprKind::IfLet(ref pat, ref expr, ref then, ref e) => {
1758                         self.cbox(INDENT_UNIT - 1)?;
1759                         self.ibox(0)?;
1760                         word(&mut self.s, " else if let ")?;
1761                         self.print_pat(&pat)?;
1762                         space(&mut self.s)?;
1763                         self.word_space("=")?;
1764                         self.print_expr(&expr)?;
1765                         space(&mut self.s)?;
1766                         self.print_block(&then)?;
1767                         self.print_else(e.as_ref().map(|e| &**e))
1768                     }
1769                     // "final else"
1770                     ast::ExprKind::Block(ref b) => {
1771                         self.cbox(INDENT_UNIT - 1)?;
1772                         self.ibox(0)?;
1773                         word(&mut self.s, " else ")?;
1774                         self.print_block(&b)
1775                     }
1776                     // BLEAH, constraints would be great here
1777                     _ => {
1778                         panic!("print_if saw if with weird alternative");
1779                     }
1780                 }
1781             }
1782             _ => Ok(())
1783         }
1784     }
1785
1786     pub fn print_if(&mut self, test: &ast::Expr, blk: &ast::Block,
1787                     elseopt: Option<&ast::Expr>) -> io::Result<()> {
1788         self.head("if")?;
1789         self.print_expr(test)?;
1790         space(&mut self.s)?;
1791         self.print_block(blk)?;
1792         self.print_else(elseopt)
1793     }
1794
1795     pub fn print_if_let(&mut self, pat: &ast::Pat, expr: &ast::Expr, blk: &ast::Block,
1796                         elseopt: Option<&ast::Expr>) -> io::Result<()> {
1797         self.head("if let")?;
1798         self.print_pat(pat)?;
1799         space(&mut self.s)?;
1800         self.word_space("=")?;
1801         self.print_expr(expr)?;
1802         space(&mut self.s)?;
1803         self.print_block(blk)?;
1804         self.print_else(elseopt)
1805     }
1806
1807     pub fn print_mac(&mut self, m: &ast::Mac, delim: token::DelimToken)
1808                      -> io::Result<()> {
1809         self.print_path(&m.node.path, false, 0, false)?;
1810         word(&mut self.s, "!")?;
1811         match delim {
1812             token::Paren => self.popen()?,
1813             token::Bracket => word(&mut self.s, "[")?,
1814             token::Brace => {
1815                 self.head("")?;
1816                 self.bopen()?;
1817             }
1818             token::NoDelim => {}
1819         }
1820         self.print_tts(m.node.stream())?;
1821         match delim {
1822             token::Paren => self.pclose(),
1823             token::Bracket => word(&mut self.s, "]"),
1824             token::Brace => self.bclose(m.span),
1825             token::NoDelim => Ok(()),
1826         }
1827     }
1828
1829
1830     fn print_call_post(&mut self, args: &[P<ast::Expr>]) -> io::Result<()> {
1831         self.popen()?;
1832         self.commasep_exprs(Inconsistent, args)?;
1833         self.pclose()
1834     }
1835
1836     pub fn check_expr_bin_needs_paren(&mut self, sub_expr: &ast::Expr,
1837                                       binop: ast::BinOp) -> bool {
1838         match sub_expr.node {
1839             ast::ExprKind::Binary(ref sub_op, _, _) => {
1840                 if AssocOp::from_ast_binop(sub_op.node).precedence() <
1841                     AssocOp::from_ast_binop(binop.node).precedence() {
1842                     true
1843                 } else {
1844                     false
1845                 }
1846             }
1847             _ => true
1848         }
1849     }
1850
1851     pub fn print_expr_maybe_paren(&mut self, expr: &ast::Expr) -> io::Result<()> {
1852         let needs_par = needs_parentheses(expr);
1853         if needs_par {
1854             self.popen()?;
1855         }
1856         self.print_expr(expr)?;
1857         if needs_par {
1858             self.pclose()?;
1859         }
1860         Ok(())
1861     }
1862
1863     fn print_expr_in_place(&mut self,
1864                            place: &ast::Expr,
1865                            expr: &ast::Expr) -> io::Result<()> {
1866         self.print_expr_maybe_paren(place)?;
1867         space(&mut self.s)?;
1868         self.word_space("<-")?;
1869         self.print_expr_maybe_paren(expr)
1870     }
1871
1872     fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>],
1873                       attrs: &[Attribute]) -> io::Result<()> {
1874         self.ibox(INDENT_UNIT)?;
1875         word(&mut self.s, "[")?;
1876         self.print_inner_attributes_inline(attrs)?;
1877         self.commasep_exprs(Inconsistent, &exprs[..])?;
1878         word(&mut self.s, "]")?;
1879         self.end()
1880     }
1881
1882     fn print_expr_repeat(&mut self,
1883                          element: &ast::Expr,
1884                          count: &ast::Expr,
1885                          attrs: &[Attribute]) -> io::Result<()> {
1886         self.ibox(INDENT_UNIT)?;
1887         word(&mut self.s, "[")?;
1888         self.print_inner_attributes_inline(attrs)?;
1889         self.print_expr(element)?;
1890         self.word_space(";")?;
1891         self.print_expr(count)?;
1892         word(&mut self.s, "]")?;
1893         self.end()
1894     }
1895
1896     fn print_expr_struct(&mut self,
1897                          path: &ast::Path,
1898                          fields: &[ast::Field],
1899                          wth: &Option<P<ast::Expr>>,
1900                          attrs: &[Attribute]) -> io::Result<()> {
1901         self.print_path(path, true, 0, false)?;
1902         word(&mut self.s, "{")?;
1903         self.print_inner_attributes_inline(attrs)?;
1904         self.commasep_cmnt(
1905             Consistent,
1906             &fields[..],
1907             |s, field| {
1908                 s.ibox(INDENT_UNIT)?;
1909                 if !field.is_shorthand {
1910                     s.print_ident(field.ident.node)?;
1911                     s.word_space(":")?;
1912                 }
1913                 s.print_expr(&field.expr)?;
1914                 s.end()
1915             },
1916             |f| f.span)?;
1917         match *wth {
1918             Some(ref expr) => {
1919                 self.ibox(INDENT_UNIT)?;
1920                 if !fields.is_empty() {
1921                     word(&mut self.s, ",")?;
1922                     space(&mut self.s)?;
1923                 }
1924                 word(&mut self.s, "..")?;
1925                 self.print_expr(&expr)?;
1926                 self.end()?;
1927             }
1928             _ => if !fields.is_empty() {
1929                 word(&mut self.s, ",")?
1930             }
1931         }
1932         word(&mut self.s, "}")?;
1933         Ok(())
1934     }
1935
1936     fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>],
1937                       attrs: &[Attribute]) -> io::Result<()> {
1938         self.popen()?;
1939         self.print_inner_attributes_inline(attrs)?;
1940         self.commasep_exprs(Inconsistent, &exprs[..])?;
1941         if exprs.len() == 1 {
1942             word(&mut self.s, ",")?;
1943         }
1944         self.pclose()
1945     }
1946
1947     fn print_expr_call(&mut self,
1948                        func: &ast::Expr,
1949                        args: &[P<ast::Expr>]) -> io::Result<()> {
1950         self.print_expr_maybe_paren(func)?;
1951         self.print_call_post(args)
1952     }
1953
1954     fn print_expr_method_call(&mut self,
1955                               ident: ast::SpannedIdent,
1956                               tys: &[P<ast::Ty>],
1957                               args: &[P<ast::Expr>]) -> io::Result<()> {
1958         let base_args = &args[1..];
1959         self.print_expr(&args[0])?;
1960         word(&mut self.s, ".")?;
1961         self.print_ident(ident.node)?;
1962         if !tys.is_empty() {
1963             word(&mut self.s, "::<")?;
1964             self.commasep(Inconsistent, tys,
1965                           |s, ty| s.print_type(&ty))?;
1966             word(&mut self.s, ">")?;
1967         }
1968         self.print_call_post(base_args)
1969     }
1970
1971     fn print_expr_binary(&mut self,
1972                          op: ast::BinOp,
1973                          lhs: &ast::Expr,
1974                          rhs: &ast::Expr) -> io::Result<()> {
1975         if self.check_expr_bin_needs_paren(lhs, op) {
1976             self.print_expr_maybe_paren(lhs)?;
1977         } else {
1978             self.print_expr(lhs)?;
1979         }
1980         space(&mut self.s)?;
1981         self.word_space(op.node.to_string())?;
1982         if self.check_expr_bin_needs_paren(rhs, op) {
1983             self.print_expr_maybe_paren(rhs)
1984         } else {
1985             self.print_expr(rhs)
1986         }
1987     }
1988
1989     fn print_expr_unary(&mut self,
1990                         op: ast::UnOp,
1991                         expr: &ast::Expr) -> io::Result<()> {
1992         word(&mut self.s, ast::UnOp::to_string(op))?;
1993         self.print_expr_maybe_paren(expr)
1994     }
1995
1996     fn print_expr_addr_of(&mut self,
1997                           mutability: ast::Mutability,
1998                           expr: &ast::Expr) -> io::Result<()> {
1999         word(&mut self.s, "&")?;
2000         self.print_mutability(mutability)?;
2001         self.print_expr_maybe_paren(expr)
2002     }
2003
2004     pub fn print_expr(&mut self, expr: &ast::Expr) -> io::Result<()> {
2005         self.print_expr_outer_attr_style(expr, true)
2006     }
2007
2008     fn print_expr_outer_attr_style(&mut self,
2009                                   expr: &ast::Expr,
2010                                   is_inline: bool) -> io::Result<()> {
2011         self.maybe_print_comment(expr.span.lo)?;
2012
2013         let attrs = &expr.attrs;
2014         if is_inline {
2015             self.print_outer_attributes_inline(attrs)?;
2016         } else {
2017             self.print_outer_attributes(attrs)?;
2018         }
2019
2020         self.ibox(INDENT_UNIT)?;
2021         self.ann.pre(self, NodeExpr(expr))?;
2022         match expr.node {
2023             ast::ExprKind::Box(ref expr) => {
2024                 self.word_space("box")?;
2025                 self.print_expr(expr)?;
2026             }
2027             ast::ExprKind::InPlace(ref place, ref expr) => {
2028                 self.print_expr_in_place(place, expr)?;
2029             }
2030             ast::ExprKind::Array(ref exprs) => {
2031                 self.print_expr_vec(&exprs[..], attrs)?;
2032             }
2033             ast::ExprKind::Repeat(ref element, ref count) => {
2034                 self.print_expr_repeat(&element, &count, attrs)?;
2035             }
2036             ast::ExprKind::Struct(ref path, ref fields, ref wth) => {
2037                 self.print_expr_struct(path, &fields[..], wth, attrs)?;
2038             }
2039             ast::ExprKind::Tup(ref exprs) => {
2040                 self.print_expr_tup(&exprs[..], attrs)?;
2041             }
2042             ast::ExprKind::Call(ref func, ref args) => {
2043                 self.print_expr_call(&func, &args[..])?;
2044             }
2045             ast::ExprKind::MethodCall(ident, ref tys, ref args) => {
2046                 self.print_expr_method_call(ident, &tys[..], &args[..])?;
2047             }
2048             ast::ExprKind::Binary(op, ref lhs, ref rhs) => {
2049                 self.print_expr_binary(op, &lhs, &rhs)?;
2050             }
2051             ast::ExprKind::Unary(op, ref expr) => {
2052                 self.print_expr_unary(op, &expr)?;
2053             }
2054             ast::ExprKind::AddrOf(m, ref expr) => {
2055                 self.print_expr_addr_of(m, &expr)?;
2056             }
2057             ast::ExprKind::Lit(ref lit) => {
2058                 self.print_literal(&lit)?;
2059             }
2060             ast::ExprKind::Cast(ref expr, ref ty) => {
2061                 if let ast::ExprKind::Cast(..) = expr.node {
2062                     self.print_expr(&expr)?;
2063                 } else {
2064                     self.print_expr_maybe_paren(&expr)?;
2065                 }
2066                 space(&mut self.s)?;
2067                 self.word_space("as")?;
2068                 self.print_type(&ty)?;
2069             }
2070             ast::ExprKind::Type(ref expr, ref ty) => {
2071                 self.print_expr(&expr)?;
2072                 self.word_space(":")?;
2073                 self.print_type(&ty)?;
2074             }
2075             ast::ExprKind::If(ref test, ref blk, ref elseopt) => {
2076                 self.print_if(&test, &blk, elseopt.as_ref().map(|e| &**e))?;
2077             }
2078             ast::ExprKind::IfLet(ref pat, ref expr, ref blk, ref elseopt) => {
2079                 self.print_if_let(&pat, &expr, &blk, elseopt.as_ref().map(|e| &**e))?;
2080             }
2081             ast::ExprKind::While(ref test, ref blk, opt_ident) => {
2082                 if let Some(ident) = opt_ident {
2083                     self.print_ident(ident.node)?;
2084                     self.word_space(":")?;
2085                 }
2086                 self.head("while")?;
2087                 self.print_expr(&test)?;
2088                 space(&mut self.s)?;
2089                 self.print_block_with_attrs(&blk, attrs)?;
2090             }
2091             ast::ExprKind::WhileLet(ref pat, ref expr, ref blk, opt_ident) => {
2092                 if let Some(ident) = opt_ident {
2093                     self.print_ident(ident.node)?;
2094                     self.word_space(":")?;
2095                 }
2096                 self.head("while let")?;
2097                 self.print_pat(&pat)?;
2098                 space(&mut self.s)?;
2099                 self.word_space("=")?;
2100                 self.print_expr(&expr)?;
2101                 space(&mut self.s)?;
2102                 self.print_block_with_attrs(&blk, attrs)?;
2103             }
2104             ast::ExprKind::ForLoop(ref pat, ref iter, ref blk, opt_ident) => {
2105                 if let Some(ident) = opt_ident {
2106                     self.print_ident(ident.node)?;
2107                     self.word_space(":")?;
2108                 }
2109                 self.head("for")?;
2110                 self.print_pat(&pat)?;
2111                 space(&mut self.s)?;
2112                 self.word_space("in")?;
2113                 self.print_expr(&iter)?;
2114                 space(&mut self.s)?;
2115                 self.print_block_with_attrs(&blk, attrs)?;
2116             }
2117             ast::ExprKind::Loop(ref blk, opt_ident) => {
2118                 if let Some(ident) = opt_ident {
2119                     self.print_ident(ident.node)?;
2120                     self.word_space(":")?;
2121                 }
2122                 self.head("loop")?;
2123                 space(&mut self.s)?;
2124                 self.print_block_with_attrs(&blk, attrs)?;
2125             }
2126             ast::ExprKind::Match(ref expr, ref arms) => {
2127                 self.cbox(INDENT_UNIT)?;
2128                 self.ibox(4)?;
2129                 self.word_nbsp("match")?;
2130                 self.print_expr(&expr)?;
2131                 space(&mut self.s)?;
2132                 self.bopen()?;
2133                 self.print_inner_attributes_no_trailing_hardbreak(attrs)?;
2134                 for arm in arms {
2135                     self.print_arm(arm)?;
2136                 }
2137                 self.bclose_(expr.span, INDENT_UNIT)?;
2138             }
2139             ast::ExprKind::Closure(capture_clause, ref decl, ref body, _) => {
2140                 self.print_capture_clause(capture_clause)?;
2141
2142                 self.print_fn_block_args(&decl)?;
2143                 space(&mut self.s)?;
2144                 self.print_expr(body)?;
2145                 self.end()?; // need to close a box
2146
2147                 // a box will be closed by print_expr, but we didn't want an overall
2148                 // wrapper so we closed the corresponding opening. so create an
2149                 // empty box to satisfy the close.
2150                 self.ibox(0)?;
2151             }
2152             ast::ExprKind::Block(ref blk) => {
2153                 // containing cbox, will be closed by print-block at }
2154                 self.cbox(INDENT_UNIT)?;
2155                 // head-box, will be closed by print-block after {
2156                 self.ibox(0)?;
2157                 self.print_block_with_attrs(&blk, attrs)?;
2158             }
2159             ast::ExprKind::Assign(ref lhs, ref rhs) => {
2160                 self.print_expr(&lhs)?;
2161                 space(&mut self.s)?;
2162                 self.word_space("=")?;
2163                 self.print_expr(&rhs)?;
2164             }
2165             ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => {
2166                 self.print_expr(&lhs)?;
2167                 space(&mut self.s)?;
2168                 word(&mut self.s, op.node.to_string())?;
2169                 self.word_space("=")?;
2170                 self.print_expr(&rhs)?;
2171             }
2172             ast::ExprKind::Field(ref expr, id) => {
2173                 self.print_expr(&expr)?;
2174                 word(&mut self.s, ".")?;
2175                 self.print_ident(id.node)?;
2176             }
2177             ast::ExprKind::TupField(ref expr, id) => {
2178                 self.print_expr(&expr)?;
2179                 word(&mut self.s, ".")?;
2180                 self.print_usize(id.node)?;
2181             }
2182             ast::ExprKind::Index(ref expr, ref index) => {
2183                 self.print_expr(&expr)?;
2184                 word(&mut self.s, "[")?;
2185                 self.print_expr(&index)?;
2186                 word(&mut self.s, "]")?;
2187             }
2188             ast::ExprKind::Range(ref start, ref end, limits) => {
2189                 if let &Some(ref e) = start {
2190                     self.print_expr(&e)?;
2191                 }
2192                 if limits == ast::RangeLimits::HalfOpen {
2193                     word(&mut self.s, "..")?;
2194                 } else {
2195                     word(&mut self.s, "...")?;
2196                 }
2197                 if let &Some(ref e) = end {
2198                     self.print_expr(&e)?;
2199                 }
2200             }
2201             ast::ExprKind::Path(None, ref path) => {
2202                 self.print_path(path, true, 0, false)?
2203             }
2204             ast::ExprKind::Path(Some(ref qself), ref path) => {
2205                 self.print_qpath(path, qself, true)?
2206             }
2207             ast::ExprKind::Break(opt_ident, ref opt_expr) => {
2208                 word(&mut self.s, "break")?;
2209                 space(&mut self.s)?;
2210                 if let Some(ident) = opt_ident {
2211                     self.print_ident(ident.node)?;
2212                     space(&mut self.s)?;
2213                 }
2214                 if let Some(ref expr) = *opt_expr {
2215                     self.print_expr(expr)?;
2216                     space(&mut self.s)?;
2217                 }
2218             }
2219             ast::ExprKind::Continue(opt_ident) => {
2220                 word(&mut self.s, "continue")?;
2221                 space(&mut self.s)?;
2222                 if let Some(ident) = opt_ident {
2223                     self.print_ident(ident.node)?;
2224                     space(&mut self.s)?
2225                 }
2226             }
2227             ast::ExprKind::Ret(ref result) => {
2228                 word(&mut self.s, "return")?;
2229                 match *result {
2230                     Some(ref expr) => {
2231                         word(&mut self.s, " ")?;
2232                         self.print_expr(&expr)?;
2233                     }
2234                     _ => ()
2235                 }
2236             }
2237             ast::ExprKind::InlineAsm(ref a) => {
2238                 word(&mut self.s, "asm!")?;
2239                 self.popen()?;
2240                 self.print_string(&a.asm.as_str(), a.asm_str_style)?;
2241                 self.word_space(":")?;
2242
2243                 self.commasep(Inconsistent, &a.outputs, |s, out| {
2244                     let constraint = out.constraint.as_str();
2245                     let mut ch = constraint.chars();
2246                     match ch.next() {
2247                         Some('=') if out.is_rw => {
2248                             s.print_string(&format!("+{}", ch.as_str()),
2249                                            ast::StrStyle::Cooked)?
2250                         }
2251                         _ => s.print_string(&constraint, ast::StrStyle::Cooked)?
2252                     }
2253                     s.popen()?;
2254                     s.print_expr(&out.expr)?;
2255                     s.pclose()?;
2256                     Ok(())
2257                 })?;
2258                 space(&mut self.s)?;
2259                 self.word_space(":")?;
2260
2261                 self.commasep(Inconsistent, &a.inputs, |s, &(co, ref o)| {
2262                     s.print_string(&co.as_str(), ast::StrStyle::Cooked)?;
2263                     s.popen()?;
2264                     s.print_expr(&o)?;
2265                     s.pclose()?;
2266                     Ok(())
2267                 })?;
2268                 space(&mut self.s)?;
2269                 self.word_space(":")?;
2270
2271                 self.commasep(Inconsistent, &a.clobbers,
2272                                    |s, co| {
2273                     s.print_string(&co.as_str(), ast::StrStyle::Cooked)?;
2274                     Ok(())
2275                 })?;
2276
2277                 let mut options = vec![];
2278                 if a.volatile {
2279                     options.push("volatile");
2280                 }
2281                 if a.alignstack {
2282                     options.push("alignstack");
2283                 }
2284                 if a.dialect == ast::AsmDialect::Intel {
2285                     options.push("intel");
2286                 }
2287
2288                 if !options.is_empty() {
2289                     space(&mut self.s)?;
2290                     self.word_space(":")?;
2291                     self.commasep(Inconsistent, &options,
2292                                   |s, &co| {
2293                                       s.print_string(co, ast::StrStyle::Cooked)?;
2294                                       Ok(())
2295                                   })?;
2296                 }
2297
2298                 self.pclose()?;
2299             }
2300             ast::ExprKind::Mac(ref m) => self.print_mac(m, token::Paren)?,
2301             ast::ExprKind::Paren(ref e) => {
2302                 self.popen()?;
2303                 self.print_inner_attributes_inline(attrs)?;
2304                 self.print_expr(&e)?;
2305                 self.pclose()?;
2306             },
2307             ast::ExprKind::Try(ref e) => {
2308                 self.print_expr(e)?;
2309                 word(&mut self.s, "?")?
2310             }
2311             ast::ExprKind::Catch(ref blk) => {
2312                 self.head("do catch")?;
2313                 space(&mut self.s)?;
2314                 self.print_block_with_attrs(&blk, attrs)?
2315             }
2316         }
2317         self.ann.post(self, NodeExpr(expr))?;
2318         self.end()
2319     }
2320
2321     pub fn print_local_decl(&mut self, loc: &ast::Local) -> io::Result<()> {
2322         self.print_pat(&loc.pat)?;
2323         if let Some(ref ty) = loc.ty {
2324             self.word_space(":")?;
2325             self.print_type(&ty)?;
2326         }
2327         Ok(())
2328     }
2329
2330     pub fn print_ident(&mut self, ident: ast::Ident) -> io::Result<()> {
2331         word(&mut self.s, &ident.name.as_str())?;
2332         self.ann.post(self, NodeIdent(&ident))
2333     }
2334
2335     pub fn print_usize(&mut self, i: usize) -> io::Result<()> {
2336         word(&mut self.s, &i.to_string())
2337     }
2338
2339     pub fn print_name(&mut self, name: ast::Name) -> io::Result<()> {
2340         word(&mut self.s, &name.as_str())?;
2341         self.ann.post(self, NodeName(&name))
2342     }
2343
2344     pub fn print_for_decl(&mut self, loc: &ast::Local,
2345                           coll: &ast::Expr) -> io::Result<()> {
2346         self.print_local_decl(loc)?;
2347         space(&mut self.s)?;
2348         self.word_space("in")?;
2349         self.print_expr(coll)
2350     }
2351
2352     fn print_path(&mut self,
2353                   path: &ast::Path,
2354                   colons_before_params: bool,
2355                   depth: usize,
2356                   defaults_to_global: bool)
2357                   -> io::Result<()>
2358     {
2359         self.maybe_print_comment(path.span.lo)?;
2360
2361         let mut segments = path.segments[..path.segments.len()-depth].iter();
2362         if defaults_to_global && path.is_global() {
2363             segments.next();
2364         }
2365         for (i, segment) in segments.enumerate() {
2366             if i > 0 {
2367                 word(&mut self.s, "::")?
2368             }
2369             if segment.identifier.name != keywords::CrateRoot.name() &&
2370                segment.identifier.name != "$crate" {
2371                 self.print_ident(segment.identifier)?;
2372                 if let Some(ref parameters) = segment.parameters {
2373                     self.print_path_parameters(parameters, colons_before_params)?;
2374                 }
2375             }
2376         }
2377
2378         Ok(())
2379     }
2380
2381     fn print_qpath(&mut self,
2382                    path: &ast::Path,
2383                    qself: &ast::QSelf,
2384                    colons_before_params: bool)
2385                    -> io::Result<()>
2386     {
2387         word(&mut self.s, "<")?;
2388         self.print_type(&qself.ty)?;
2389         if qself.position > 0 {
2390             space(&mut self.s)?;
2391             self.word_space("as")?;
2392             let depth = path.segments.len() - qself.position;
2393             self.print_path(&path, false, depth, false)?;
2394         }
2395         word(&mut self.s, ">")?;
2396         word(&mut self.s, "::")?;
2397         let item_segment = path.segments.last().unwrap();
2398         self.print_ident(item_segment.identifier)?;
2399         match item_segment.parameters {
2400             Some(ref parameters) => self.print_path_parameters(parameters, colons_before_params),
2401             None => Ok(()),
2402         }
2403     }
2404
2405     fn print_path_parameters(&mut self,
2406                              parameters: &ast::PathParameters,
2407                              colons_before_params: bool)
2408                              -> io::Result<()>
2409     {
2410         if colons_before_params {
2411             word(&mut self.s, "::")?
2412         }
2413
2414         match *parameters {
2415             ast::PathParameters::AngleBracketed(ref data) => {
2416                 word(&mut self.s, "<")?;
2417
2418                 let mut comma = false;
2419                 for lifetime in &data.lifetimes {
2420                     if comma {
2421                         self.word_space(",")?
2422                     }
2423                     self.print_lifetime(lifetime)?;
2424                     comma = true;
2425                 }
2426
2427                 if !data.types.is_empty() {
2428                     if comma {
2429                         self.word_space(",")?
2430                     }
2431                     self.commasep(
2432                         Inconsistent,
2433                         &data.types,
2434                         |s, ty| s.print_type(&ty))?;
2435                         comma = true;
2436                 }
2437
2438                 for binding in data.bindings.iter() {
2439                     if comma {
2440                         self.word_space(",")?
2441                     }
2442                     self.print_ident(binding.ident)?;
2443                     space(&mut self.s)?;
2444                     self.word_space("=")?;
2445                     self.print_type(&binding.ty)?;
2446                     comma = true;
2447                 }
2448
2449                 word(&mut self.s, ">")?
2450             }
2451
2452             ast::PathParameters::Parenthesized(ref data) => {
2453                 word(&mut self.s, "(")?;
2454                 self.commasep(
2455                     Inconsistent,
2456                     &data.inputs,
2457                     |s, ty| s.print_type(&ty))?;
2458                 word(&mut self.s, ")")?;
2459
2460                 if let Some(ref ty) = data.output {
2461                     self.space_if_not_bol()?;
2462                     self.word_space("->")?;
2463                     self.print_type(&ty)?;
2464                 }
2465             }
2466         }
2467
2468         Ok(())
2469     }
2470
2471     pub fn print_pat(&mut self, pat: &ast::Pat) -> io::Result<()> {
2472         self.maybe_print_comment(pat.span.lo)?;
2473         self.ann.pre(self, NodePat(pat))?;
2474         /* Pat isn't normalized, but the beauty of it
2475          is that it doesn't matter */
2476         match pat.node {
2477             PatKind::Wild => word(&mut self.s, "_")?,
2478             PatKind::Ident(binding_mode, ref path1, ref sub) => {
2479                 match binding_mode {
2480                     ast::BindingMode::ByRef(mutbl) => {
2481                         self.word_nbsp("ref")?;
2482                         self.print_mutability(mutbl)?;
2483                     }
2484                     ast::BindingMode::ByValue(ast::Mutability::Immutable) => {}
2485                     ast::BindingMode::ByValue(ast::Mutability::Mutable) => {
2486                         self.word_nbsp("mut")?;
2487                     }
2488                 }
2489                 self.print_ident(path1.node)?;
2490                 if let Some(ref p) = *sub {
2491                     word(&mut self.s, "@")?;
2492                     self.print_pat(&p)?;
2493                 }
2494             }
2495             PatKind::TupleStruct(ref path, ref elts, ddpos) => {
2496                 self.print_path(path, true, 0, false)?;
2497                 self.popen()?;
2498                 if let Some(ddpos) = ddpos {
2499                     self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(&p))?;
2500                     if ddpos != 0 {
2501                         self.word_space(",")?;
2502                     }
2503                     word(&mut self.s, "..")?;
2504                     if ddpos != elts.len() {
2505                         word(&mut self.s, ",")?;
2506                         self.commasep(Inconsistent, &elts[ddpos..], |s, p| s.print_pat(&p))?;
2507                     }
2508                 } else {
2509                     self.commasep(Inconsistent, &elts[..], |s, p| s.print_pat(&p))?;
2510                 }
2511                 self.pclose()?;
2512             }
2513             PatKind::Path(None, ref path) => {
2514                 self.print_path(path, true, 0, false)?;
2515             }
2516             PatKind::Path(Some(ref qself), ref path) => {
2517                 self.print_qpath(path, qself, false)?;
2518             }
2519             PatKind::Struct(ref path, ref fields, etc) => {
2520                 self.print_path(path, true, 0, false)?;
2521                 self.nbsp()?;
2522                 self.word_space("{")?;
2523                 self.commasep_cmnt(
2524                     Consistent, &fields[..],
2525                     |s, f| {
2526                         s.cbox(INDENT_UNIT)?;
2527                         if !f.node.is_shorthand {
2528                             s.print_ident(f.node.ident)?;
2529                             s.word_nbsp(":")?;
2530                         }
2531                         s.print_pat(&f.node.pat)?;
2532                         s.end()
2533                     },
2534                     |f| f.node.pat.span)?;
2535                 if etc {
2536                     if !fields.is_empty() { self.word_space(",")?; }
2537                     word(&mut self.s, "..")?;
2538                 }
2539                 space(&mut self.s)?;
2540                 word(&mut self.s, "}")?;
2541             }
2542             PatKind::Tuple(ref elts, ddpos) => {
2543                 self.popen()?;
2544                 if let Some(ddpos) = ddpos {
2545                     self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(&p))?;
2546                     if ddpos != 0 {
2547                         self.word_space(",")?;
2548                     }
2549                     word(&mut self.s, "..")?;
2550                     if ddpos != elts.len() {
2551                         word(&mut self.s, ",")?;
2552                         self.commasep(Inconsistent, &elts[ddpos..], |s, p| s.print_pat(&p))?;
2553                     }
2554                 } else {
2555                     self.commasep(Inconsistent, &elts[..], |s, p| s.print_pat(&p))?;
2556                     if elts.len() == 1 {
2557                         word(&mut self.s, ",")?;
2558                     }
2559                 }
2560                 self.pclose()?;
2561             }
2562             PatKind::Box(ref inner) => {
2563                 word(&mut self.s, "box ")?;
2564                 self.print_pat(&inner)?;
2565             }
2566             PatKind::Ref(ref inner, mutbl) => {
2567                 word(&mut self.s, "&")?;
2568                 if mutbl == ast::Mutability::Mutable {
2569                     word(&mut self.s, "mut ")?;
2570                 }
2571                 self.print_pat(&inner)?;
2572             }
2573             PatKind::Lit(ref e) => self.print_expr(&**e)?,
2574             PatKind::Range(ref begin, ref end, ref end_kind) => {
2575                 self.print_expr(&begin)?;
2576                 space(&mut self.s)?;
2577                 match *end_kind {
2578                     RangeEnd::Included => word(&mut self.s, "...")?,
2579                     RangeEnd::Excluded => word(&mut self.s, "..")?,
2580                 }
2581                 self.print_expr(&end)?;
2582             }
2583             PatKind::Slice(ref before, ref slice, ref after) => {
2584                 word(&mut self.s, "[")?;
2585                 self.commasep(Inconsistent,
2586                                    &before[..],
2587                                    |s, p| s.print_pat(&p))?;
2588                 if let Some(ref p) = *slice {
2589                     if !before.is_empty() { self.word_space(",")?; }
2590                     if p.node != PatKind::Wild {
2591                         self.print_pat(&p)?;
2592                     }
2593                     word(&mut self.s, "..")?;
2594                     if !after.is_empty() { self.word_space(",")?; }
2595                 }
2596                 self.commasep(Inconsistent,
2597                                    &after[..],
2598                                    |s, p| s.print_pat(&p))?;
2599                 word(&mut self.s, "]")?;
2600             }
2601             PatKind::Mac(ref m) => self.print_mac(m, token::Paren)?,
2602         }
2603         self.ann.post(self, NodePat(pat))
2604     }
2605
2606     fn print_arm(&mut self, arm: &ast::Arm) -> io::Result<()> {
2607         // I have no idea why this check is necessary, but here it
2608         // is :(
2609         if arm.attrs.is_empty() {
2610             space(&mut self.s)?;
2611         }
2612         self.cbox(INDENT_UNIT)?;
2613         self.ibox(0)?;
2614         self.maybe_print_comment(arm.pats[0].span.lo)?;
2615         self.print_outer_attributes(&arm.attrs)?;
2616         let mut first = true;
2617         for p in &arm.pats {
2618             if first {
2619                 first = false;
2620             } else {
2621                 space(&mut self.s)?;
2622                 self.word_space("|")?;
2623             }
2624             self.print_pat(&p)?;
2625         }
2626         space(&mut self.s)?;
2627         if let Some(ref e) = arm.guard {
2628             self.word_space("if")?;
2629             self.print_expr(&e)?;
2630             space(&mut self.s)?;
2631         }
2632         self.word_space("=>")?;
2633
2634         match arm.body.node {
2635             ast::ExprKind::Block(ref blk) => {
2636                 // the block will close the pattern's ibox
2637                 self.print_block_unclosed_indent(&blk, INDENT_UNIT)?;
2638
2639                 // If it is a user-provided unsafe block, print a comma after it
2640                 if let BlockCheckMode::Unsafe(ast::UserProvided) = blk.rules {
2641                     word(&mut self.s, ",")?;
2642                 }
2643             }
2644             _ => {
2645                 self.end()?; // close the ibox for the pattern
2646                 self.print_expr(&arm.body)?;
2647                 word(&mut self.s, ",")?;
2648             }
2649         }
2650         self.end() // close enclosing cbox
2651     }
2652
2653     fn print_explicit_self(&mut self, explicit_self: &ast::ExplicitSelf) -> io::Result<()> {
2654         match explicit_self.node {
2655             SelfKind::Value(m) => {
2656                 self.print_mutability(m)?;
2657                 word(&mut self.s, "self")
2658             }
2659             SelfKind::Region(ref lt, m) => {
2660                 word(&mut self.s, "&")?;
2661                 self.print_opt_lifetime(lt)?;
2662                 self.print_mutability(m)?;
2663                 word(&mut self.s, "self")
2664             }
2665             SelfKind::Explicit(ref typ, m) => {
2666                 self.print_mutability(m)?;
2667                 word(&mut self.s, "self")?;
2668                 self.word_space(":")?;
2669                 self.print_type(&typ)
2670             }
2671         }
2672     }
2673
2674     pub fn print_fn(&mut self,
2675                     decl: &ast::FnDecl,
2676                     unsafety: ast::Unsafety,
2677                     constness: ast::Constness,
2678                     abi: abi::Abi,
2679                     name: Option<ast::Ident>,
2680                     generics: &ast::Generics,
2681                     vis: &ast::Visibility) -> io::Result<()> {
2682         self.print_fn_header_info(unsafety, constness, abi, vis)?;
2683
2684         if let Some(name) = name {
2685             self.nbsp()?;
2686             self.print_ident(name)?;
2687         }
2688         self.print_generics(generics)?;
2689         self.print_fn_args_and_ret(decl)?;
2690         self.print_where_clause(&generics.where_clause)
2691     }
2692
2693     pub fn print_fn_args_and_ret(&mut self, decl: &ast::FnDecl)
2694         -> io::Result<()> {
2695         self.popen()?;
2696         self.commasep(Inconsistent, &decl.inputs, |s, arg| s.print_arg(arg, false))?;
2697         if decl.variadic {
2698             word(&mut self.s, ", ...")?;
2699         }
2700         self.pclose()?;
2701
2702         self.print_fn_output(decl)
2703     }
2704
2705     pub fn print_fn_block_args(
2706             &mut self,
2707             decl: &ast::FnDecl)
2708             -> io::Result<()> {
2709         word(&mut self.s, "|")?;
2710         self.commasep(Inconsistent, &decl.inputs, |s, arg| s.print_arg(arg, true))?;
2711         word(&mut self.s, "|")?;
2712
2713         if let ast::FunctionRetTy::Default(..) = decl.output {
2714             return Ok(());
2715         }
2716
2717         self.space_if_not_bol()?;
2718         self.word_space("->")?;
2719         match decl.output {
2720             ast::FunctionRetTy::Ty(ref ty) => {
2721                 self.print_type(&ty)?;
2722                 self.maybe_print_comment(ty.span.lo)
2723             }
2724             ast::FunctionRetTy::Default(..) => unreachable!(),
2725         }
2726     }
2727
2728     pub fn print_capture_clause(&mut self, capture_clause: ast::CaptureBy)
2729                                 -> io::Result<()> {
2730         match capture_clause {
2731             ast::CaptureBy::Value => self.word_space("move"),
2732             ast::CaptureBy::Ref => Ok(()),
2733         }
2734     }
2735
2736     pub fn print_bounds(&mut self,
2737                         prefix: &str,
2738                         bounds: &[ast::TyParamBound])
2739                         -> io::Result<()> {
2740         if !bounds.is_empty() {
2741             word(&mut self.s, prefix)?;
2742             let mut first = true;
2743             for bound in bounds {
2744                 self.nbsp()?;
2745                 if first {
2746                     first = false;
2747                 } else {
2748                     self.word_space("+")?;
2749                 }
2750
2751                 (match *bound {
2752                     TraitTyParamBound(ref tref, TraitBoundModifier::None) => {
2753                         self.print_poly_trait_ref(tref)
2754                     }
2755                     TraitTyParamBound(ref tref, TraitBoundModifier::Maybe) => {
2756                         word(&mut self.s, "?")?;
2757                         self.print_poly_trait_ref(tref)
2758                     }
2759                     RegionTyParamBound(ref lt) => {
2760                         self.print_lifetime(lt)
2761                     }
2762                 })?
2763             }
2764             Ok(())
2765         } else {
2766             Ok(())
2767         }
2768     }
2769
2770     pub fn print_lifetime(&mut self,
2771                           lifetime: &ast::Lifetime)
2772                           -> io::Result<()>
2773     {
2774         self.print_name(lifetime.name)
2775     }
2776
2777     pub fn print_lifetime_bounds(&mut self,
2778                                  lifetime: &ast::Lifetime,
2779                                  bounds: &[ast::Lifetime])
2780                                  -> io::Result<()>
2781     {
2782         self.print_lifetime(lifetime)?;
2783         if !bounds.is_empty() {
2784             word(&mut self.s, ": ")?;
2785             for (i, bound) in bounds.iter().enumerate() {
2786                 if i != 0 {
2787                     word(&mut self.s, " + ")?;
2788                 }
2789                 self.print_lifetime(bound)?;
2790             }
2791         }
2792         Ok(())
2793     }
2794
2795     pub fn print_generics(&mut self,
2796                           generics: &ast::Generics)
2797                           -> io::Result<()>
2798     {
2799         let total = generics.lifetimes.len() + generics.ty_params.len();
2800         if total == 0 {
2801             return Ok(());
2802         }
2803
2804         word(&mut self.s, "<")?;
2805
2806         let mut ints = Vec::new();
2807         for i in 0..total {
2808             ints.push(i);
2809         }
2810
2811         self.commasep(Inconsistent, &ints[..], |s, &idx| {
2812             if idx < generics.lifetimes.len() {
2813                 let lifetime_def = &generics.lifetimes[idx];
2814                 s.print_outer_attributes_inline(&lifetime_def.attrs)?;
2815                 s.print_lifetime_bounds(&lifetime_def.lifetime, &lifetime_def.bounds)
2816             } else {
2817                 let idx = idx - generics.lifetimes.len();
2818                 let param = &generics.ty_params[idx];
2819                 s.print_ty_param(param)
2820             }
2821         })?;
2822
2823         word(&mut self.s, ">")?;
2824         Ok(())
2825     }
2826
2827     pub fn print_ty_param(&mut self, param: &ast::TyParam) -> io::Result<()> {
2828         self.print_outer_attributes_inline(&param.attrs)?;
2829         self.print_ident(param.ident)?;
2830         self.print_bounds(":", &param.bounds)?;
2831         match param.default {
2832             Some(ref default) => {
2833                 space(&mut self.s)?;
2834                 self.word_space("=")?;
2835                 self.print_type(&default)
2836             }
2837             _ => Ok(())
2838         }
2839     }
2840
2841     pub fn print_where_clause(&mut self, where_clause: &ast::WhereClause)
2842                               -> io::Result<()> {
2843         if where_clause.predicates.is_empty() {
2844             return Ok(())
2845         }
2846
2847         space(&mut self.s)?;
2848         self.word_space("where")?;
2849
2850         for (i, predicate) in where_clause.predicates.iter().enumerate() {
2851             if i != 0 {
2852                 self.word_space(",")?;
2853             }
2854
2855             match *predicate {
2856                 ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate{ref bound_lifetimes,
2857                                                                              ref bounded_ty,
2858                                                                              ref bounds,
2859                                                                              ..}) => {
2860                     self.print_formal_lifetime_list(bound_lifetimes)?;
2861                     self.print_type(&bounded_ty)?;
2862                     self.print_bounds(":", bounds)?;
2863                 }
2864                 ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate{ref lifetime,
2865                                                                                ref bounds,
2866                                                                                ..}) => {
2867                     self.print_lifetime_bounds(lifetime, bounds)?;
2868                 }
2869                 ast::WherePredicate::EqPredicate(ast::WhereEqPredicate{ref lhs_ty,
2870                                                                        ref rhs_ty,
2871                                                                        ..}) => {
2872                     self.print_type(lhs_ty)?;
2873                     space(&mut self.s)?;
2874                     self.word_space("=")?;
2875                     self.print_type(rhs_ty)?;
2876                 }
2877             }
2878         }
2879
2880         Ok(())
2881     }
2882
2883     pub fn print_view_path(&mut self, vp: &ast::ViewPath) -> io::Result<()> {
2884         match vp.node {
2885             ast::ViewPathSimple(ident, ref path) => {
2886                 self.print_path(path, false, 0, true)?;
2887
2888                 if path.segments.last().unwrap().identifier.name !=
2889                         ident.name {
2890                     space(&mut self.s)?;
2891                     self.word_space("as")?;
2892                     self.print_ident(ident)?;
2893                 }
2894
2895                 Ok(())
2896             }
2897
2898             ast::ViewPathGlob(ref path) => {
2899                 self.print_path(path, false, 0, true)?;
2900                 word(&mut self.s, "::*")
2901             }
2902
2903             ast::ViewPathList(ref path, ref idents) => {
2904                 if path.segments.is_empty() {
2905                     word(&mut self.s, "{")?;
2906                 } else {
2907                     self.print_path(path, false, 0, true)?;
2908                     word(&mut self.s, "::{")?;
2909                 }
2910                 self.commasep(Inconsistent, &idents[..], |s, w| {
2911                     s.print_ident(w.node.name)?;
2912                     if let Some(ident) = w.node.rename {
2913                         space(&mut s.s)?;
2914                         s.word_space("as")?;
2915                         s.print_ident(ident)?;
2916                     }
2917                     Ok(())
2918                 })?;
2919                 word(&mut self.s, "}")
2920             }
2921         }
2922     }
2923
2924     pub fn print_mutability(&mut self,
2925                             mutbl: ast::Mutability) -> io::Result<()> {
2926         match mutbl {
2927             ast::Mutability::Mutable => self.word_nbsp("mut"),
2928             ast::Mutability::Immutable => Ok(()),
2929         }
2930     }
2931
2932     pub fn print_mt(&mut self, mt: &ast::MutTy) -> io::Result<()> {
2933         self.print_mutability(mt.mutbl)?;
2934         self.print_type(&mt.ty)
2935     }
2936
2937     pub fn print_arg(&mut self, input: &ast::Arg, is_closure: bool) -> io::Result<()> {
2938         self.ibox(INDENT_UNIT)?;
2939         match input.ty.node {
2940             ast::TyKind::Infer if is_closure => self.print_pat(&input.pat)?,
2941             _ => {
2942                 if let Some(eself) = input.to_self() {
2943                     self.print_explicit_self(&eself)?;
2944                 } else {
2945                     let invalid = if let PatKind::Ident(_, ident, _) = input.pat.node {
2946                         ident.node.name == keywords::Invalid.name()
2947                     } else {
2948                         false
2949                     };
2950                     if !invalid {
2951                         self.print_pat(&input.pat)?;
2952                         word(&mut self.s, ":")?;
2953                         space(&mut self.s)?;
2954                     }
2955                     self.print_type(&input.ty)?;
2956                 }
2957             }
2958         }
2959         self.end()
2960     }
2961
2962     pub fn print_fn_output(&mut self, decl: &ast::FnDecl) -> io::Result<()> {
2963         if let ast::FunctionRetTy::Default(..) = decl.output {
2964             return Ok(());
2965         }
2966
2967         self.space_if_not_bol()?;
2968         self.ibox(INDENT_UNIT)?;
2969         self.word_space("->")?;
2970         match decl.output {
2971             ast::FunctionRetTy::Default(..) => unreachable!(),
2972             ast::FunctionRetTy::Ty(ref ty) =>
2973                 self.print_type(&ty)?
2974         }
2975         self.end()?;
2976
2977         match decl.output {
2978             ast::FunctionRetTy::Ty(ref output) => self.maybe_print_comment(output.span.lo),
2979             _ => Ok(())
2980         }
2981     }
2982
2983     pub fn print_ty_fn(&mut self,
2984                        abi: abi::Abi,
2985                        unsafety: ast::Unsafety,
2986                        decl: &ast::FnDecl,
2987                        name: Option<ast::Ident>,
2988                        generics: &ast::Generics)
2989                        -> io::Result<()> {
2990         self.ibox(INDENT_UNIT)?;
2991         if !generics.lifetimes.is_empty() || !generics.ty_params.is_empty() {
2992             word(&mut self.s, "for")?;
2993             self.print_generics(generics)?;
2994         }
2995         let generics = ast::Generics {
2996             lifetimes: Vec::new(),
2997             ty_params: Vec::new(),
2998             where_clause: ast::WhereClause {
2999                 id: ast::DUMMY_NODE_ID,
3000                 predicates: Vec::new(),
3001             },
3002             span: syntax_pos::DUMMY_SP,
3003         };
3004         self.print_fn(decl,
3005                       unsafety,
3006                       ast::Constness::NotConst,
3007                       abi,
3008                       name,
3009                       &generics,
3010                       &ast::Visibility::Inherited)?;
3011         self.end()
3012     }
3013
3014     pub fn maybe_print_trailing_comment(&mut self, span: syntax_pos::Span,
3015                                         next_pos: Option<BytePos>)
3016         -> io::Result<()> {
3017         let cm = match self.cm {
3018             Some(cm) => cm,
3019             _ => return Ok(())
3020         };
3021         if let Some(ref cmnt) = self.next_comment() {
3022             if cmnt.style != comments::Trailing { return Ok(()) }
3023             let span_line = cm.lookup_char_pos(span.hi);
3024             let comment_line = cm.lookup_char_pos(cmnt.pos);
3025             let next = next_pos.unwrap_or(cmnt.pos + BytePos(1));
3026             if span.hi < cmnt.pos && cmnt.pos < next && span_line.line == comment_line.line {
3027                 self.print_comment(cmnt)?;
3028                 self.cur_cmnt_and_lit.cur_cmnt += 1;
3029             }
3030         }
3031         Ok(())
3032     }
3033
3034     pub fn print_remaining_comments(&mut self) -> io::Result<()> {
3035         // If there aren't any remaining comments, then we need to manually
3036         // make sure there is a line break at the end.
3037         if self.next_comment().is_none() {
3038             hardbreak(&mut self.s)?;
3039         }
3040         loop {
3041             match self.next_comment() {
3042                 Some(ref cmnt) => {
3043                     self.print_comment(cmnt)?;
3044                     self.cur_cmnt_and_lit.cur_cmnt += 1;
3045                 }
3046                 _ => break
3047             }
3048         }
3049         Ok(())
3050     }
3051
3052     pub fn print_opt_abi_and_extern_if_nondefault(&mut self,
3053                                                   opt_abi: Option<Abi>)
3054         -> io::Result<()> {
3055         match opt_abi {
3056             Some(Abi::Rust) => Ok(()),
3057             Some(abi) => {
3058                 self.word_nbsp("extern")?;
3059                 self.word_nbsp(&abi.to_string())
3060             }
3061             None => Ok(())
3062         }
3063     }
3064
3065     pub fn print_extern_opt_abi(&mut self,
3066                                 opt_abi: Option<Abi>) -> io::Result<()> {
3067         match opt_abi {
3068             Some(abi) => {
3069                 self.word_nbsp("extern")?;
3070                 self.word_nbsp(&abi.to_string())
3071             }
3072             None => Ok(())
3073         }
3074     }
3075
3076     pub fn print_fn_header_info(&mut self,
3077                                 unsafety: ast::Unsafety,
3078                                 constness: ast::Constness,
3079                                 abi: Abi,
3080                                 vis: &ast::Visibility) -> io::Result<()> {
3081         word(&mut self.s, &visibility_qualified(vis, ""))?;
3082
3083         match constness {
3084             ast::Constness::NotConst => {}
3085             ast::Constness::Const => self.word_nbsp("const")?
3086         }
3087
3088         self.print_unsafety(unsafety)?;
3089
3090         if abi != Abi::Rust {
3091             self.word_nbsp("extern")?;
3092             self.word_nbsp(&abi.to_string())?;
3093         }
3094
3095         word(&mut self.s, "fn")
3096     }
3097
3098     pub fn print_unsafety(&mut self, s: ast::Unsafety) -> io::Result<()> {
3099         match s {
3100             ast::Unsafety::Normal => Ok(()),
3101             ast::Unsafety::Unsafe => self.word_nbsp("unsafe"),
3102         }
3103     }
3104 }
3105
3106 fn repeat(s: &str, n: usize) -> String { iter::repeat(s).take(n).collect() }
3107
3108 #[cfg(test)]
3109 mod tests {
3110     use super::*;
3111
3112     use ast;
3113     use codemap;
3114     use syntax_pos;
3115
3116     #[test]
3117     fn test_fun_to_string() {
3118         let abba_ident = ast::Ident::from_str("abba");
3119
3120         let decl = ast::FnDecl {
3121             inputs: Vec::new(),
3122             output: ast::FunctionRetTy::Default(syntax_pos::DUMMY_SP),
3123             variadic: false
3124         };
3125         let generics = ast::Generics::default();
3126         assert_eq!(fun_to_string(&decl, ast::Unsafety::Normal,
3127                                  ast::Constness::NotConst,
3128                                  abba_ident, &generics),
3129                    "fn abba()");
3130     }
3131
3132     #[test]
3133     fn test_variant_to_string() {
3134         let ident = ast::Ident::from_str("principal_skinner");
3135
3136         let var = codemap::respan(syntax_pos::DUMMY_SP, ast::Variant_ {
3137             name: ident,
3138             attrs: Vec::new(),
3139             // making this up as I go.... ?
3140             data: ast::VariantData::Unit(ast::DUMMY_NODE_ID),
3141             disr_expr: None,
3142         });
3143
3144         let varstr = variant_to_string(&var);
3145         assert_eq!(varstr, "principal_skinner");
3146     }
3147 }