src/types.rs

   1 // Copyright 2015 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 use std::ops::Deref;
  12 use std::iter::ExactSizeIterator;
  13
  14 use syntax::ast::{self, Mutability, FunctionRetTy};
  15 use syntax::print::pprust;
  16 use syntax::codemap::{self, Span, BytePos};
  17 use syntax::abi;
  18
  19 use {Indent, Spanned};
  20 use lists::{format_item_list, itemize_list, format_fn_args};
  21 use rewrite::{Rewrite, RewriteContext};
  22 use utils::{CodeMapSpanUtils, extra_offset, format_mutability, wrap_str};
  23 use expr::{rewrite_unary_prefix, rewrite_pair, rewrite_tuple};
  24 use config::TypeDensity;
  25
  26 // Does not wrap on simple segments.
  27 pub fn rewrite_path(context: &RewriteContext,
  28                     expr_context: bool,
  29                     qself: Option<&ast::QSelf>,
  30                     path: &ast::Path,
  31                     width: usize,
  32                     offset: Indent)
  33                     -> Option<String> {
  34     let skip_count = qself.map_or(0, |x| x.position);
  35
  36     let mut result = if path.global {
  37         "::".to_owned()
  38     } else {
  39         String::new()
  40     };
  41
  42     let mut span_lo = path.span.lo;
  43
  44     if let Some(ref qself) = qself {
  45         result.push('<');
  46         let fmt_ty = try_opt!(qself.ty.rewrite(context, width, offset));
  47         result.push_str(&fmt_ty);
  48
  49         if skip_count > 0 {
  50             result.push_str(" as ");
  51
  52             let extra_offset = extra_offset(&result, offset);
  53             // 3 = ">::".len()
  54             let budget = try_opt!(width.checked_sub(extra_offset + 3));
  55
  56             result = try_opt!(rewrite_path_segments(false,
  57                                                     result,
  58                                                     path.segments.iter().take(skip_count),
  59                                                     span_lo,
  60                                                     path.span.hi,
  61                                                     context,
  62                                                     budget,
  63                                                     offset + extra_offset));
  64         }
  65
  66         result.push_str(">::");
  67         span_lo = qself.ty.span.hi + BytePos(1);
  68     }
  69
  70     let extra_offset = extra_offset(&result, offset);
  71     let budget = try_opt!(width.checked_sub(extra_offset));
  72     rewrite_path_segments(expr_context,
  73                           result,
  74                           path.segments.iter().skip(skip_count),
  75                           span_lo,
  76                           path.span.hi,
  77                           context,
  78                           budget,
  79                           offset + extra_offset)
  80 }
  81
  82 fn rewrite_path_segments<'a, I>(expr_context: bool,
  83                                 mut buffer: String,
  84                                 iter: I,
  85                                 mut span_lo: BytePos,
  86                                 span_hi: BytePos,
  87                                 context: &RewriteContext,
  88                                 width: usize,
  89                                 offset: Indent)
  90                                 -> Option<String>
  91     where I: Iterator<Item = &'a ast::PathSegment>
  92 {
  93     let mut first = true;
  94
  95     for segment in iter {
  96         if first {
  97             first = false;
  98         } else {
  99             buffer.push_str("::");
 100         }
 101
 102         let extra_offset = extra_offset(&buffer, offset);
 103         let remaining_width = try_opt!(width.checked_sub(extra_offset));
 104         let new_offset = offset + extra_offset;
 105         let segment_string = try_opt!(rewrite_segment(expr_context,
 106                                                       segment,
 107                                                       &mut span_lo,
 108                                                       span_hi,
 109                                                       context,
 110                                                       remaining_width,
 111                                                       new_offset));
 112
 113         buffer.push_str(&segment_string);
 114     }
 115
 116     Some(buffer)
 117 }
 118
 119 #[derive(Debug)]
 120 enum SegmentParam<'a> {
 121     LifeTime(&'a ast::Lifetime),
 122     Type(&'a ast::Ty),
 123     Binding(&'a ast::TypeBinding),
 124 }
 125
 126 impl<'a> SegmentParam<'a> {
 127     fn get_span(&self) -> Span {
 128         match *self {
 129             SegmentParam::LifeTime(ref lt) => lt.span,
 130             SegmentParam::Type(ref ty) => ty.span,
 131             SegmentParam::Binding(ref binding) => binding.span,
 132         }
 133     }
 134 }
 135
 136 impl<'a> Rewrite for SegmentParam<'a> {
 137     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 138         match *self {
 139             SegmentParam::LifeTime(ref lt) => lt.rewrite(context, width, offset),
 140             SegmentParam::Type(ref ty) => ty.rewrite(context, width, offset),
 141             SegmentParam::Binding(ref binding) => {
 142                 let mut result = format!("{} = ", binding.ident);
 143                 let budget = try_opt!(width.checked_sub(result.len()));
 144                 let rewrite = try_opt!(binding.ty.rewrite(context, budget, offset + result.len()));
 145                 result.push_str(&rewrite);
 146                 Some(result)
 147             }
 148         }
 149     }
 150 }
 151
 152 // Formats a path segment. There are some hacks involved to correctly determine
 153 // the segment's associated span since it's not part of the AST.
 154 //
 155 // The span_lo is assumed to be greater than the end of any previous segment's
 156 // parameters and lesser or equal than the start of current segment.
 157 //
 158 // span_hi is assumed equal to the end of the entire path.
 159 //
 160 // When the segment contains a positive number of parameters, we update span_lo
 161 // so that invariants described above will hold for the next segment.
 162 fn rewrite_segment(expr_context: bool,
 163                    segment: &ast::PathSegment,
 164                    span_lo: &mut BytePos,
 165                    span_hi: BytePos,
 166                    context: &RewriteContext,
 167                    width: usize,
 168                    offset: Indent)
 169                    -> Option<String> {
 170     let ident_len = segment.identifier.to_string().len();
 171     let width = try_opt!(width.checked_sub(ident_len));
 172     let offset = offset + ident_len;
 173
 174     let params = match segment.parameters {
 175         ast::PathParameters::AngleBracketed(ref data) if !data.lifetimes.is_empty() ||
 176                                                          !data.types.is_empty() ||
 177                                                          !data.bindings.is_empty() => {
 178             let param_list = data.lifetimes
 179                 .iter()
 180                 .map(SegmentParam::LifeTime)
 181                 .chain(data.types.iter().map(|x| SegmentParam::Type(&*x)))
 182                 .chain(data.bindings.iter().map(|x| SegmentParam::Binding(&*x)))
 183                 .collect::<Vec<_>>();
 184
 185             let next_span_lo = param_list.last().unwrap().get_span().hi + BytePos(1);
 186             let list_lo = context.codemap.span_after(codemap::mk_sp(*span_lo, span_hi), "<");
 187             let separator = if expr_context {
 188                 "::"
 189             } else {
 190                 ""
 191             };
 192
 193             // 1 for <
 194             let extra_offset = 1 + separator.len();
 195             // 1 for >
 196             let list_width = try_opt!(width.checked_sub(extra_offset + 1));
 197
 198             let items = itemize_list(context.codemap,
 199                                      param_list.into_iter(),
 200                                      ">",
 201                                      |param| param.get_span().lo,
 202                                      |param| param.get_span().hi,
 203                                      |seg| seg.rewrite(context, list_width, offset + extra_offset),
 204                                      list_lo,
 205                                      span_hi);
 206             let list_str = try_opt!(format_item_list(items,
 207                                                      list_width,
 208                                                      offset + extra_offset,
 209                                                      context.config));
 210
 211             // Update position of last bracket.
 212             *span_lo = next_span_lo;
 213
 214             format!("{}<{}>", separator, list_str)
 215         }
 216         ast::PathParameters::Parenthesized(ref data) => {
 217             let output = match data.output {
 218                 Some(ref ty) => FunctionRetTy::Ty(ty.clone()),
 219                 None => FunctionRetTy::Default(codemap::DUMMY_SP),
 220             };
 221             try_opt!(format_function_type(data.inputs.iter().map(|x| &**x),
 222                                           &output,
 223                                           false,
 224                                           data.span,
 225                                           context,
 226                                           width,
 227                                           offset))
 228         }
 229         _ => String::new(),
 230     };
 231
 232     Some(format!("{}{}", segment.identifier, params))
 233 }
 234
 235 fn format_function_type<'a, I>(inputs: I,
 236                                output: &FunctionRetTy,
 237                                variadic: bool,
 238                                span: Span,
 239                                context: &RewriteContext,
 240                                width: usize,
 241                                offset: Indent)
 242                                -> Option<String>
 243     where I: ExactSizeIterator,
 244           <I as Iterator>::Item: Deref,
 245           <I::Item as Deref>::Target: Rewrite + Spanned + 'a
 246 {
 247     // Code for handling variadics is somewhat duplicated for items, but they
 248     // are different enough to need some serious refactoring to share code.
 249     enum ArgumentKind<T>
 250         where T: Deref,
 251               <T as Deref>::Target: Rewrite + Spanned
 252     {
 253         Regular(Box<T>),
 254         Variadic(BytePos),
 255     }
 256
 257     let variadic_arg = if variadic {
 258         let variadic_start = context.codemap.span_before(span, "...");
 259         Some(ArgumentKind::Variadic(variadic_start))
 260     } else {
 261         None
 262     };
 263
 264     // 2 for ()
 265     let budget = try_opt!(width.checked_sub(2));
 266     // 1 for (
 267     let offset = offset + 1;
 268     let list_lo = context.codemap.span_after(span, "(");
 269     let items = itemize_list(context.codemap,
 270                              // FIXME Would be nice to avoid this allocation,
 271                              // but I couldn't get the types to work out.
 272                              inputs.map(|i| ArgumentKind::Regular(Box::new(i)))
 273                                  .chain(variadic_arg),
 274                              ")",
 275                              |arg| {
 276                                  match *arg {
 277                                      ArgumentKind::Regular(ref ty) => ty.span().lo,
 278                                      ArgumentKind::Variadic(start) => start,
 279                                  }
 280                              },
 281                              |arg| {
 282                                  match *arg {
 283                                      ArgumentKind::Regular(ref ty) => ty.span().hi,
 284                                      ArgumentKind::Variadic(start) => start + BytePos(3),
 285                                  }
 286                              },
 287                              |arg| {
 288         match *arg {
 289             ArgumentKind::Regular(ref ty) => ty.rewrite(context, budget, offset),
 290             ArgumentKind::Variadic(_) => Some("...".to_owned()),
 291         }
 292     },
 293                              list_lo,
 294                              span.hi);
 295
 296     let list_str = try_opt!(format_fn_args(items, budget, offset, context.config));
 297
 298     let output = match *output {
 299         FunctionRetTy::Ty(ref ty) => {
 300             let budget = try_opt!(width.checked_sub(4));
 301             let type_str = try_opt!(ty.rewrite(context, budget, offset + 4));
 302             format!(" -> {}", type_str)
 303         }
 304         FunctionRetTy::None(..) => " -> !".to_owned(),
 305         FunctionRetTy::Default(..) => String::new(),
 306     };
 307
 308     let infix = if output.len() > 0 && output.len() + list_str.len() > width {
 309         format!("\n{}", (offset - 1).to_string(context.config))
 310     } else {
 311         String::new()
 312     };
 313
 314     Some(format!("({}){}{}", list_str, infix, output))
 315 }
 316
 317 impl Rewrite for ast::WherePredicate {
 318     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 319         // TODO: dead spans?
 320         let result = match *self {
 321             ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate { ref bound_lifetimes,
 322                                                                            ref bounded_ty,
 323                                                                            ref bounds,
 324                                                                            .. }) => {
 325                 let type_str = try_opt!(bounded_ty.rewrite(context, width, offset));
 326
 327                 if !bound_lifetimes.is_empty() {
 328                     let lifetime_str = try_opt!(bound_lifetimes.iter()
 329                                                                .map(|lt| {
 330                                                                    lt.rewrite(context,
 331                                                                               width,
 332                                                                               offset)
 333                                                                })
 334                                                                .collect::<Option<Vec<_>>>())
 335                                            .join(", ");
 336                     // 8 = "for<> : ".len()
 337                     let used_width = lifetime_str.len() + type_str.len() + 8;
 338                     let budget = try_opt!(width.checked_sub(used_width));
 339                     let bounds_str = try_opt!(bounds.iter()
 340                                                     .map(|ty_bound| {
 341                                                         ty_bound.rewrite(context,
 342                                                                          budget,
 343                                                                          offset + used_width)
 344                                                     })
 345                                                     .collect::<Option<Vec<_>>>())
 346                                          .join(" + ");
 347
 348                     format!("for<{}> {}: {}", lifetime_str, type_str, bounds_str)
 349                 } else {
 350                     // 2 = ": ".len()
 351                     let used_width = type_str.len() + 2;
 352                     let budget = try_opt!(width.checked_sub(used_width));
 353                     let bounds_str = try_opt!(bounds.iter()
 354                                                     .map(|ty_bound| {
 355                                                         ty_bound.rewrite(context,
 356                                                                          budget,
 357                                                                          offset + used_width)
 358                                                     })
 359                                                     .collect::<Option<Vec<_>>>())
 360                                          .join(" + ");
 361
 362                     format!("{}: {}", type_str, bounds_str)
 363                 }
 364             }
 365             ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate { ref lifetime,
 366                                                                              ref bounds,
 367                                                                              .. }) => {
 368                 try_opt!(rewrite_bounded_lifetime(lifetime, bounds.iter(), context, width, offset))
 369             }
 370             ast::WherePredicate::EqPredicate(ast::WhereEqPredicate { ref path, ref ty, .. }) => {
 371                 let ty_str = try_opt!(ty.rewrite(context, width, offset));
 372                 // 3 = " = ".len()
 373                 let used_width = 3 + ty_str.len();
 374                 let budget = try_opt!(width.checked_sub(used_width));
 375                 let path_str = try_opt!(rewrite_path(context,
 376                                                      false,
 377                                                      None,
 378                                                      path,
 379                                                      budget,
 380                                                      offset + used_width));
 381                 format!("{} = {}", path_str, ty_str)
 382             }
 383         };
 384
 385         wrap_str(result, context.config.max_width, width, offset)
 386     }
 387 }
 388
 389 impl Rewrite for ast::LifetimeDef {
 390     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 391         rewrite_bounded_lifetime(&self.lifetime, self.bounds.iter(), context, width, offset)
 392     }
 393 }
 394
 395 fn rewrite_bounded_lifetime<'b, I>(lt: &ast::Lifetime,
 396                                    bounds: I,
 397                                    context: &RewriteContext,
 398                                    width: usize,
 399                                    offset: Indent)
 400                                    -> Option<String>
 401     where I: ExactSizeIterator<Item = &'b ast::Lifetime>
 402 {
 403     let result = try_opt!(lt.rewrite(context, width, offset));
 404
 405     if bounds.len() == 0 {
 406         Some(result)
 407     } else {
 408         let appendix: Vec<_> = try_opt!(bounds.into_iter()
 409             .map(|b| b.rewrite(context, width, offset))
 410             .collect());
 411         let result = format!("{}: {}", result, appendix.join(" + "));
 412         wrap_str(result, context.config.max_width, width, offset)
 413     }
 414 }
 415
 416 impl Rewrite for ast::TyParamBound {
 417     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 418         match *self {
 419             ast::TyParamBound::TraitTyParamBound(ref tref, ast::TraitBoundModifier::None) => {
 420                 tref.rewrite(context, width, offset)
 421             }
 422             ast::TyParamBound::TraitTyParamBound(ref tref, ast::TraitBoundModifier::Maybe) => {
 423                 let budget = try_opt!(width.checked_sub(1));
 424                 Some(format!("?{}", try_opt!(tref.rewrite(context, budget, offset + 1))))
 425             }
 426             ast::TyParamBound::RegionTyParamBound(ref l) => l.rewrite(context, width, offset),
 427         }
 428     }
 429 }
 430
 431 impl Rewrite for ast::Lifetime {
 432     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 433         wrap_str(pprust::lifetime_to_string(self),
 434                  context.config.max_width,
 435                  width,
 436                  offset)
 437     }
 438 }
 439
 440 impl Rewrite for ast::TyParamBounds {
 441     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 442         let strs: Vec<_> = try_opt!(self.iter()
 443             .map(|b| b.rewrite(context, width, offset))
 444             .collect());
 445         wrap_str(strs.join(" + "), context.config.max_width, width, offset)
 446     }
 447 }
 448
 449 impl Rewrite for ast::TyParam {
 450     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 451         let mut result = String::with_capacity(128);
 452         result.push_str(&self.ident.to_string());
 453         if !self.bounds.is_empty() {
 454             result.push_str(": ");
 455
 456             let bounds = try_opt!(self.bounds
 457                     .iter()
 458                     .map(|ty_bound| ty_bound.rewrite(context, width, offset))
 459                     .collect::<Option<Vec<_>>>())
 460                 .join(" + ");
 461
 462             result.push_str(&bounds);
 463         }
 464         if let Some(ref def) = self.default {
 465
 466             let eq_str = match context.config.type_punctuation_density {
 467                 TypeDensity::Compressed => "=",
 468                 TypeDensity::Wide => " = ",
 469             };
 470             result.push_str(eq_str);
 471             let budget = try_opt!(width.checked_sub(result.len()));
 472             let rewrite = try_opt!(def.rewrite(context, budget, offset + result.len()));
 473             result.push_str(&rewrite);
 474         }
 475
 476         wrap_str(result, context.config.max_width, width, offset)
 477     }
 478 }
 479
 480 impl Rewrite for ast::PolyTraitRef {
 481     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 482         if !self.bound_lifetimes.is_empty() {
 483             let lifetime_str = try_opt!(self.bound_lifetimes
 484                     .iter()
 485                     .map(|lt| lt.rewrite(context, width, offset))
 486                     .collect::<Option<Vec<_>>>())
 487                 .join(", ");
 488             // 6 is "for<> ".len()
 489             let extra_offset = lifetime_str.len() + 6;
 490             let max_path_width = try_opt!(width.checked_sub(extra_offset));
 491             let path_str = try_opt!(self.trait_ref
 492                 .rewrite(context, max_path_width, offset + extra_offset));
 493
 494             Some(format!("for<{}> {}", lifetime_str, path_str))
 495         } else {
 496             self.trait_ref.rewrite(context, width, offset)
 497         }
 498     }
 499 }
 500
 501 impl Rewrite for ast::TraitRef {
 502     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 503         rewrite_path(context, false, None, &self.path, width, offset)
 504     }
 505 }
 506
 507 impl Rewrite for ast::Ty {
 508     fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
 509         match self.node {
 510             ast::TyKind::ObjectSum(ref ty, ref bounds) => {
 511                 let ty_str = try_opt!(ty.rewrite(context, width, offset));
 512                 let overhead = ty_str.len() + 3;
 513                 let plus_str = match context.config.type_punctuation_density {
 514                     TypeDensity::Compressed => "+",
 515                     TypeDensity::Wide => " + ",
 516                 };
 517                 Some(format!("{}{}{}",
 518                              ty_str,
 519                              plus_str,
 520                              try_opt!(bounds.rewrite(context,
 521                                                      try_opt!(width.checked_sub(overhead)),
 522                                                      offset + overhead))))
 523             }
 524             ast::TyKind::Ptr(ref mt) => {
 525                 let prefix = match mt.mutbl {
 526                     Mutability::Mutable => "*mut ",
 527                     Mutability::Immutable => "*const ",
 528                 };
 529
 530                 rewrite_unary_prefix(context, prefix, &*mt.ty, width, offset)
 531             }
 532             ast::TyKind::Rptr(ref lifetime, ref mt) => {
 533                 let mut_str = format_mutability(mt.mutbl);
 534                 let mut_len = mut_str.len();
 535                 Some(match *lifetime {
 536                     Some(ref lifetime) => {
 537                         let lt_budget = try_opt!(width.checked_sub(2 + mut_len));
 538                         let lt_str = try_opt!(lifetime.rewrite(context,
 539                                                                lt_budget,
 540                                                                offset + 2 + mut_len));
 541                         let lt_len = lt_str.len();
 542                         let budget = try_opt!(width.checked_sub(2 + mut_len + lt_len));
 543                         format!("&{} {}{}",
 544                                 lt_str,
 545                                 mut_str,
 546                                 try_opt!(mt.ty
 547                                     .rewrite(context, budget, offset + 2 + mut_len + lt_len)))
 548                     }
 549                     None => {
 550                         let budget = try_opt!(width.checked_sub(1 + mut_len));
 551                         format!("&{}{}",
 552                                 mut_str,
 553                                 try_opt!(mt.ty.rewrite(context, budget, offset + 1 + mut_len)))
 554                     }
 555                 })
 556             }
 557             // FIXME: we drop any comments here, even though it's a silly place to put
 558             // comments.
 559             ast::TyKind::Paren(ref ty) => {
 560                 let budget = try_opt!(width.checked_sub(2));
 561                 ty.rewrite(context, budget, offset + 1).map(|ty_str| format!("({})", ty_str))
 562             }
 563             ast::TyKind::Vec(ref ty) => {
 564                 let budget = try_opt!(width.checked_sub(2));
 565                 ty.rewrite(context, budget, offset + 1).map(|ty_str| format!("[{}]", ty_str))
 566             }
 567             ast::TyKind::Tup(ref items) => {
 568                 rewrite_tuple(context,
 569                               items.iter().map(|x| &**x),
 570                               self.span,
 571                               width,
 572                               offset)
 573             }
 574             ast::TyKind::PolyTraitRef(ref trait_ref) => trait_ref.rewrite(context, width, offset),
 575             ast::TyKind::Path(ref q_self, ref path) => {
 576                 rewrite_path(context, false, q_self.as_ref(), path, width, offset)
 577             }
 578             ast::TyKind::FixedLengthVec(ref ty, ref repeats) => {
 579                 rewrite_pair(&**ty, &**repeats, "[", "; ", "]", context, width, offset)
 580             }
 581             ast::TyKind::Infer => {
 582                 if width >= 1 {
 583                     Some("_".to_owned())
 584                 } else {
 585                     None
 586                 }
 587             }
 588             ast::TyKind::BareFn(ref bare_fn) => {
 589                 rewrite_bare_fn(bare_fn, self.span, context, width, offset)
 590             }
 591             ast::TyKind::Mac(..) |
 592             ast::TyKind::Typeof(..) => unreachable!(),
 593         }
 594     }
 595 }
 596
 597 fn rewrite_bare_fn(bare_fn: &ast::BareFnTy,
 598                    span: Span,
 599                    context: &RewriteContext,
 600                    width: usize,
 601                    offset: Indent)
 602                    -> Option<String> {
 603     let mut result = String::with_capacity(128);
 604
 605     result.push_str(&::utils::format_unsafety(bare_fn.unsafety));
 606
 607     if bare_fn.abi != abi::Abi::Rust {
 608         result.push_str(&::utils::format_abi(bare_fn.abi, context.config.force_explicit_abi));
 609     }
 610
 611     result.push_str("fn");
 612
 613     let budget = try_opt!(width.checked_sub(result.len()));
 614     let indent = offset + result.len();
 615
 616     let rewrite = try_opt!(format_function_type(bare_fn.decl.inputs.iter(),
 617                                                 &bare_fn.decl.output,
 618                                                 bare_fn.decl.variadic,
 619                                                 span,
 620                                                 context,
 621                                                 budget,
 622                                                 indent));
 623
 624     result.push_str(&rewrite);
 625
 626     Some(result)
 627 }