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.
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.
11 use std::cmp::{min, Ordering};
13 use std::iter::ExactSizeIterator;
15 use syntax::{ast, ptr};
16 use syntax::codemap::{BytePos, CodeMap, Span};
17 use syntax::parse::classify;
19 use {Indent, Shape, Spanned};
20 use chains::rewrite_chain;
21 use codemap::{LineRangeUtils, SpanUtils};
22 use comment::{combine_strs_with_missing_comments, contains_comment, recover_comment_removed,
23 rewrite_comment, FindUncommented};
24 use config::{Config, ControlBraceStyle, IndentStyle, MultilineStyle, Style};
25 use items::{span_hi_for_arg, span_lo_for_arg};
26 use lists::{definitive_tactic, itemize_list, shape_for_tactic, struct_lit_formatting,
27 struct_lit_shape, struct_lit_tactic, write_list, DefinitiveListTactic, ListFormatting,
28 ListItem, ListTactic, Separator, SeparatorTactic};
29 use macros::{rewrite_macro, MacroPosition};
30 use patterns::{can_be_overflowed_pat, TuplePatField};
31 use rewrite::{Rewrite, RewriteContext};
32 use string::{rewrite_string, StringFormat};
33 use types::{can_be_overflowed_type, rewrite_path, PathContext};
34 use utils::{binary_search, colon_spaces, contains_skip, extra_offset, first_line_width,
35 inner_attributes, last_line_extendable, last_line_width, left_most_sub_expr, mk_sp,
36 outer_attributes, paren_overhead, semicolon_for_stmt, stmt_expr,
37 trimmed_last_line_width, wrap_str};
38 use vertical::rewrite_with_alignment;
39 use visitor::FmtVisitor;
41 impl Rewrite for ast::Expr {
42 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
43 format_expr(self, ExprType::SubExpression, context, shape)
56 context: &RewriteContext,
59 skip_out_of_file_lines_range!(context, expr.span);
61 if contains_skip(&*expr.attrs) {
62 return Some(context.snippet(expr.span()));
65 let expr_rw = match expr.node {
66 ast::ExprKind::Array(ref expr_vec) => rewrite_array(
67 expr_vec.iter().map(|e| &**e),
68 mk_sp(context.codemap.span_after(expr.span, "["), expr.span.hi),
73 ast::ExprKind::Lit(ref l) => match l.node {
74 ast::LitKind::Str(_, ast::StrStyle::Cooked) => {
75 rewrite_string_lit(context, l.span, shape)
78 context.snippet(expr.span),
79 context.config.max_width(),
83 ast::ExprKind::Call(ref callee, ref args) => {
84 let inner_span = mk_sp(callee.span.hi, expr.span.hi);
85 rewrite_call_with_binary_search(
88 &args.iter().map(|x| &**x).collect::<Vec<_>>()[..],
93 ast::ExprKind::Paren(ref subexpr) => rewrite_paren(context, subexpr, shape),
94 ast::ExprKind::Binary(ref op, ref lhs, ref rhs) => {
95 // FIXME: format comments between operands and operator
100 &format!(" {} ", context.snippet(op.span)),
106 ast::ExprKind::Unary(ref op, ref subexpr) => rewrite_unary_op(context, op, subexpr, shape),
107 ast::ExprKind::Struct(ref path, ref fields, ref base) => rewrite_struct_lit(
111 base.as_ref().map(|e| &**e),
115 ast::ExprKind::Tup(ref items) => rewrite_tuple(
117 &items.iter().map(|x| &**x).collect::<Vec<_>>()[..],
121 ast::ExprKind::If(..) |
122 ast::ExprKind::IfLet(..) |
123 ast::ExprKind::ForLoop(..) |
124 ast::ExprKind::Loop(..) |
125 ast::ExprKind::While(..) |
126 ast::ExprKind::WhileLet(..) => to_control_flow(expr, expr_type)
127 .and_then(|control_flow| control_flow.rewrite(context, shape)),
128 ast::ExprKind::Block(ref block) => {
130 ExprType::Statement => {
131 if is_unsafe_block(block) {
132 block.rewrite(context, shape)
134 // Rewrite block without trying to put it in a single line.
135 if let rw @ Some(_) = rewrite_empty_block(context, block, shape) {
138 let prefix = try_opt!(block_prefix(context, block, shape));
139 rewrite_block_with_visitor(context, &prefix, block, shape)
142 ExprType::SubExpression => block.rewrite(context, shape),
145 ast::ExprKind::Match(ref cond, ref arms) => {
146 rewrite_match(context, cond, arms, shape, expr.span, &expr.attrs)
148 ast::ExprKind::Path(ref qself, ref path) => {
149 rewrite_path(context, PathContext::Expr, qself.as_ref(), path, shape)
151 ast::ExprKind::Assign(ref lhs, ref rhs) => {
152 rewrite_assignment(context, lhs, rhs, None, shape)
154 ast::ExprKind::AssignOp(ref op, ref lhs, ref rhs) => {
155 rewrite_assignment(context, lhs, rhs, Some(op), shape)
157 ast::ExprKind::Continue(ref opt_ident) => {
158 let id_str = match *opt_ident {
159 Some(ident) => format!(" {}", ident.node),
160 None => String::new(),
163 format!("continue{}", id_str),
164 context.config.max_width(),
168 ast::ExprKind::Break(ref opt_ident, ref opt_expr) => {
169 let id_str = match *opt_ident {
170 Some(ident) => format!(" {}", ident.node),
171 None => String::new(),
174 if let Some(ref expr) = *opt_expr {
175 rewrite_unary_prefix(context, &format!("break{} ", id_str), &**expr, shape)
178 format!("break{}", id_str),
179 context.config.max_width(),
184 ast::ExprKind::Closure(capture, ref fn_decl, ref body, _) => {
185 rewrite_closure(capture, fn_decl, body, expr.span, context, shape)
187 ast::ExprKind::Try(..) |
188 ast::ExprKind::Field(..) |
189 ast::ExprKind::TupField(..) |
190 ast::ExprKind::MethodCall(..) => rewrite_chain(expr, context, shape),
191 ast::ExprKind::Mac(ref mac) => {
192 // Failure to rewrite a marco should not imply failure to
193 // rewrite the expression.
194 rewrite_macro(mac, None, context, shape, MacroPosition::Expression).or_else(|| {
196 context.snippet(expr.span),
197 context.config.max_width(),
202 ast::ExprKind::Ret(None) => {
203 wrap_str("return".to_owned(), context.config.max_width(), shape)
205 ast::ExprKind::Ret(Some(ref expr)) => {
206 rewrite_unary_prefix(context, "return ", &**expr, shape)
208 ast::ExprKind::Box(ref expr) => rewrite_unary_prefix(context, "box ", &**expr, shape),
209 ast::ExprKind::AddrOf(mutability, ref expr) => {
210 rewrite_expr_addrof(context, mutability, expr, shape)
212 ast::ExprKind::Cast(ref expr, ref ty) => {
213 rewrite_pair(&**expr, &**ty, "", " as ", "", context, shape)
215 ast::ExprKind::Type(ref expr, ref ty) => {
216 rewrite_pair(&**expr, &**ty, "", ": ", "", context, shape)
218 ast::ExprKind::Index(ref expr, ref index) => {
219 rewrite_index(&**expr, &**index, context, shape)
221 ast::ExprKind::Repeat(ref expr, ref repeats) => {
222 let (lbr, rbr) = if context.config.spaces_within_square_brackets() {
227 rewrite_pair(&**expr, &**repeats, lbr, "; ", rbr, context, shape)
229 ast::ExprKind::Range(ref lhs, ref rhs, limits) => {
230 let delim = match limits {
231 ast::RangeLimits::HalfOpen => "..",
232 ast::RangeLimits::Closed => "...",
235 fn needs_space_before_range(context: &RewriteContext, lhs: &ast::Expr) -> bool {
237 ast::ExprKind::Lit(ref lit) => match lit.node {
238 ast::LitKind::FloatUnsuffixed(..) => {
239 context.snippet(lit.span).ends_with('.')
247 match (lhs.as_ref().map(|x| &**x), rhs.as_ref().map(|x| &**x)) {
248 (Some(ref lhs), Some(ref rhs)) => {
249 let sp_delim = if context.config.spaces_around_ranges() {
250 format!(" {} ", delim)
251 } else if needs_space_before_range(context, lhs) {
252 format!(" {}", delim)
256 rewrite_pair(&**lhs, &**rhs, "", &sp_delim, "", context, shape)
258 (None, Some(ref rhs)) => {
259 let sp_delim = if context.config.spaces_around_ranges() {
260 format!("{} ", delim)
264 rewrite_unary_prefix(context, &sp_delim, &**rhs, shape)
266 (Some(ref lhs), None) => {
267 let sp_delim = if context.config.spaces_around_ranges() {
268 format!(" {}", delim)
272 rewrite_unary_suffix(context, &sp_delim, &**lhs, shape)
274 (None, None) => wrap_str(delim.into(), context.config.max_width(), shape),
277 // We do not format these expressions yet, but they should still
278 // satisfy our width restrictions.
279 ast::ExprKind::InPlace(..) | ast::ExprKind::InlineAsm(..) => wrap_str(
280 context.snippet(expr.span),
281 context.config.max_width(),
284 ast::ExprKind::Catch(ref block) => {
285 if let rewrite @ Some(_) = rewrite_single_line_block(context, "do catch ", block, shape)
290 let budget = shape.width.checked_sub(9).unwrap_or(0);
294 try_opt!(block.rewrite(&context, Shape::legacy(budget, shape.indent)))
300 .and_then(|expr_str| {
301 recover_comment_removed(expr_str, expr.span, context, shape)
303 .and_then(|expr_str| {
304 let attrs = outer_attributes(&expr.attrs);
305 let attrs_str = try_opt!(attrs.rewrite(context, shape));
307 attrs.last().map_or(expr.span.lo, |attr| attr.span.hi),
310 combine_strs_with_missing_comments(context, &attrs_str, &expr_str, span, shape, false)
314 pub fn rewrite_pair<LHS, RHS>(
320 context: &RewriteContext,
327 let sep = if infix.ends_with(' ') { " " } else { "" };
328 let infix = infix.trim_right();
329 let lhs_overhead = shape.used_width() + prefix.len() + infix.len();
330 let lhs_shape = Shape {
331 width: try_opt!(context.config.max_width().checked_sub(lhs_overhead)),
334 let lhs_result = try_opt!(
335 lhs.rewrite(context, lhs_shape)
336 .map(|lhs_str| format!("{}{}{}", prefix, lhs_str, infix))
339 // Try to the both lhs and rhs on the same line.
340 let rhs_orig_result = shape
341 .offset_left(last_line_width(&lhs_result) + suffix.len() + sep.len())
342 .and_then(|rhs_shape| rhs.rewrite(context, rhs_shape));
343 if let Some(ref rhs_result) = rhs_orig_result {
344 // If the rhs looks like block expression, we allow it to stay on the same line
345 // with the lhs even if it is multi-lined.
346 let allow_same_line = rhs_result
349 .map(|first_line| first_line.ends_with('{'))
351 if !rhs_result.contains('\n') || allow_same_line {
352 return Some(format!("{}{}{}{}", lhs_result, sep, rhs_result, suffix));
356 // We have to use multiple lines.
357 // Re-evaluate the rhs because we have more space now:
358 let rhs_shape = match context.config.control_style() {
360 try_opt!(shape.sub_width(suffix.len() + prefix.len())).visual_indent(prefix.len())
363 // Try to calculate the initial constraint on the right hand side.
364 let rhs_overhead = shape.rhs_overhead(context.config);
366 Shape::indented(shape.indent.block_indent(context.config), context.config)
367 .sub_width(rhs_overhead)
371 let rhs_result = try_opt!(rhs.rewrite(context, rhs_shape));
375 rhs_shape.indent.to_string(context.config),
381 pub fn rewrite_array<'a, I>(
384 context: &RewriteContext,
386 trailing_comma: bool,
389 I: Iterator<Item = &'a ast::Expr>,
391 let bracket_size = if context.config.spaces_within_square_brackets() {
397 let mut nested_shape = match context.config.array_layout() {
398 IndentStyle::Block => try_opt!(
401 .block_indent(context.config.tab_spaces())
402 .with_max_width(context.config)
405 IndentStyle::Visual => try_opt!(
407 .visual_indent(bracket_size)
408 .sub_width(bracket_size * 2)
412 let items = itemize_list(
418 |item| item.rewrite(context, nested_shape),
422 ).collect::<Vec<_>>();
424 if items.is_empty() {
425 if context.config.spaces_within_square_brackets() {
426 return Some("[ ]".to_string());
428 return Some("[]".to_string());
432 let has_long_item = items
434 .any(|li| li.item.as_ref().map(|s| s.len() > 10).unwrap_or(false));
436 let mut tactic = match context.config.array_layout() {
437 IndentStyle::Block => {
438 // FIXME wrong shape in one-line case
439 match shape.width.checked_sub(2 * bracket_size) {
442 ListTactic::LimitedHorizontalVertical(context.config.array_width());
443 definitive_tactic(&items, tactic, Separator::Comma, width)
445 None => DefinitiveListTactic::Vertical,
448 IndentStyle::Visual => if has_long_item || items.iter().any(ListItem::is_multiline) {
451 ListTactic::LimitedHorizontalVertical(context.config.array_width()),
456 DefinitiveListTactic::Mixed
459 let mut ends_with_newline = tactic.ends_with_newline(context.config.array_layout());
460 if context.config.array_horizontal_layout_threshold() > 0 &&
461 items.len() > context.config.array_horizontal_layout_threshold()
463 tactic = DefinitiveListTactic::Mixed;
464 ends_with_newline = false;
465 if context.config.array_layout() == IndentStyle::Block {
466 nested_shape = try_opt!(
468 .visual_indent(bracket_size)
469 .sub_width(bracket_size * 2)
474 let fmt = ListFormatting {
477 trailing_separator: if trailing_comma {
478 SeparatorTactic::Always
479 } else if context.inside_macro || context.config.array_layout() == IndentStyle::Visual {
480 SeparatorTactic::Never
482 SeparatorTactic::Vertical
485 ends_with_newline: ends_with_newline,
486 preserve_newline: false,
487 config: context.config,
489 let list_str = try_opt!(write_list(&items, &fmt));
491 let result = if context.config.array_layout() == IndentStyle::Visual ||
492 tactic != DefinitiveListTactic::Vertical
494 if context.config.spaces_within_square_brackets() && list_str.len() > 0 {
495 format!("[ {} ]", list_str)
497 format!("[{}]", list_str)
502 nested_shape.indent.to_string(context.config),
504 shape.block().indent.to_string(context.config)
511 // Return type is (prefix, extra_offset)
512 fn rewrite_closure_fn_decl(
513 capture: ast::CaptureBy,
514 fn_decl: &ast::FnDecl,
517 context: &RewriteContext,
519 ) -> Option<(String, usize)> {
520 let mover = if capture == ast::CaptureBy::Value {
525 // 4 = "|| {".len(), which is overconservative when the closure consists of
526 // a single expression.
527 let nested_shape = try_opt!(try_opt!(shape.shrink_left(mover.len())).sub_width(4));
530 let argument_offset = nested_shape.indent + 1;
531 let arg_shape = try_opt!(nested_shape.offset_left(1)).visual_indent(0);
532 let ret_str = try_opt!(fn_decl.output.rewrite(context, arg_shape));
534 let arg_items = itemize_list(
536 fn_decl.inputs.iter(),
538 |arg| span_lo_for_arg(arg),
539 |arg| span_hi_for_arg(context, arg),
540 |arg| arg.rewrite(context, arg_shape),
541 context.codemap.span_after(span, "|"),
545 let item_vec = arg_items.collect::<Vec<_>>();
546 // 1 = space between arguments and return type.
547 let horizontal_budget = nested_shape
549 .checked_sub(ret_str.len() + 1)
551 let tactic = definitive_tactic(
553 ListTactic::HorizontalVertical,
557 let arg_shape = match tactic {
558 DefinitiveListTactic::Horizontal => try_opt!(arg_shape.sub_width(ret_str.len() + 1)),
562 let fmt = ListFormatting {
565 trailing_separator: SeparatorTactic::Never,
567 ends_with_newline: false,
568 preserve_newline: true,
569 config: context.config,
571 let list_str = try_opt!(write_list(&item_vec, &fmt));
572 let mut prefix = format!("{}|{}|", mover, list_str);
573 // 1 = space between `|...|` and body.
574 let extra_offset = extra_offset(&prefix, shape) + 1;
576 if !ret_str.is_empty() {
577 if prefix.contains('\n') {
579 prefix.push_str(&argument_offset.to_string(context.config));
583 prefix.push_str(&ret_str);
586 Some((prefix, extra_offset))
589 // This functions is pretty messy because of the rules around closures and blocks:
590 // FIXME - the below is probably no longer true in full.
591 // * if there is a return type, then there must be braces,
592 // * given a closure with braces, whether that is parsed to give an inner block
593 // or not depends on if there is a return type and if there are statements
595 // * if the first expression in the body ends with a block (i.e., is a
596 // statement without needing a semi-colon), then adding or removing braces
597 // can change whether it is treated as an expression or statement.
599 capture: ast::CaptureBy,
600 fn_decl: &ast::FnDecl,
603 context: &RewriteContext,
605 ) -> Option<String> {
606 let (prefix, extra_offset) = try_opt!(rewrite_closure_fn_decl(
614 // 1 = space between `|...|` and body.
615 let body_shape = try_opt!(shape.offset_left(extra_offset));
617 if let ast::ExprKind::Block(ref block) = body.node {
618 // The body of the closure is an empty block.
619 if block.stmts.is_empty() && !block_contains_comment(block, context.codemap) {
620 return Some(format!("{} {{}}", prefix));
623 // Figure out if the block is necessary.
624 let needs_block = block.rules != ast::BlockCheckMode::Default || block.stmts.len() > 1 ||
625 context.inside_macro ||
626 block_contains_comment(block, context.codemap) ||
627 prefix.contains('\n');
629 let no_return_type = if let ast::FunctionRetTy::Default(_) = fn_decl.output {
634 if no_return_type && !needs_block {
635 // lock.stmts.len() == 1
636 if let Some(ref expr) = stmt_expr(&block.stmts[0]) {
637 if let Some(rw) = rewrite_closure_expr(expr, &prefix, context, body_shape) {
644 // We need braces, but we might still prefer a one-liner.
645 let stmt = &block.stmts[0];
646 // 4 = braces and spaces.
647 if let Some(body_shape) = body_shape.sub_width(4) {
648 // Checks if rewrite succeeded and fits on a single line.
649 if let Some(rewrite) = and_one_line(stmt.rewrite(context, body_shape)) {
650 return Some(format!("{} {{ {} }}", prefix, rewrite));
655 // Either we require a block, or tried without and failed.
656 rewrite_closure_block(&block, &prefix, context, body_shape)
658 rewrite_closure_expr(body, &prefix, context, body_shape).or_else(|| {
659 // The closure originally had a non-block expression, but we can't fit on
660 // one line, so we'll insert a block.
661 rewrite_closure_with_block(context, body_shape, &prefix, body)
666 // Rewrite closure with a single expression wrapping its body with block.
667 fn rewrite_closure_with_block(
668 context: &RewriteContext,
672 ) -> Option<String> {
673 let block = ast::Block {
676 id: ast::NodeId::new(0),
677 node: ast::StmtKind::Expr(ptr::P(body.clone())),
681 id: ast::NodeId::new(0),
682 rules: ast::BlockCheckMode::Default,
685 rewrite_closure_block(&block, prefix, context, shape)
688 // Rewrite closure with a single expression without wrapping its body with block.
689 fn rewrite_closure_expr(
692 context: &RewriteContext,
694 ) -> Option<String> {
695 let mut rewrite = expr.rewrite(context, shape);
696 if classify::expr_requires_semi_to_be_stmt(left_most_sub_expr(expr)) {
697 rewrite = and_one_line(rewrite);
699 rewrite.map(|rw| format!("{} {}", prefix, rw))
702 // Rewrite closure whose body is block.
703 fn rewrite_closure_block(
706 context: &RewriteContext,
708 ) -> Option<String> {
709 // Start with visual indent, then fall back to block indent if the
711 let block_threshold = context.config.closure_block_indent_threshold();
712 if block_threshold >= 0 {
713 if let Some(block_str) = block.rewrite(&context, shape) {
714 if block_str.matches('\n').count() <= block_threshold as usize &&
715 !need_block_indent(&block_str, shape)
717 if let Some(block_str) = block_str.rewrite(context, shape) {
718 return Some(format!("{} {}", prefix, block_str));
724 // The body of the closure is big enough to be block indented, that
725 // means we must re-format.
726 let block_shape = shape.block();
727 let block_str = try_opt!(block.rewrite(&context, block_shape));
728 Some(format!("{} {}", prefix, block_str))
731 fn and_one_line(x: Option<String>) -> Option<String> {
732 x.and_then(|x| if x.contains('\n') { None } else { Some(x) })
735 fn nop_block_collapse(block_str: Option<String>, budget: usize) -> Option<String> {
736 debug!("nop_block_collapse {:?} {}", block_str, budget);
737 block_str.map(|block_str| {
738 if block_str.starts_with('{') && budget >= 2 &&
739 (block_str[1..].find(|c: char| !c.is_whitespace()).unwrap() == block_str.len() - 2)
748 fn rewrite_empty_block(
749 context: &RewriteContext,
752 ) -> Option<String> {
753 if block.stmts.is_empty() && !block_contains_comment(block, context.codemap) && shape.width >= 2
755 return Some("{}".to_owned());
758 // If a block contains only a single-line comment, then leave it on one line.
759 let user_str = context.snippet(block.span);
760 let user_str = user_str.trim();
761 if user_str.starts_with('{') && user_str.ends_with('}') {
762 let comment_str = user_str[1..user_str.len() - 1].trim();
763 if block.stmts.is_empty() && !comment_str.contains('\n') &&
764 !comment_str.starts_with("//") && comment_str.len() + 4 <= shape.width
766 return Some(format!("{{ {} }}", comment_str));
773 fn block_prefix(context: &RewriteContext, block: &ast::Block, shape: Shape) -> Option<String> {
774 Some(match block.rules {
775 ast::BlockCheckMode::Unsafe(..) => {
776 let snippet = context.snippet(block.span);
777 let open_pos = try_opt!(snippet.find_uncommented("{"));
778 // Extract comment between unsafe and block start.
779 let trimmed = &snippet[6..open_pos].trim();
781 if !trimmed.is_empty() {
782 // 9 = "unsafe {".len(), 7 = "unsafe ".len()
783 let budget = try_opt!(shape.width.checked_sub(9));
786 try_opt!(rewrite_comment(
789 Shape::legacy(budget, shape.indent + 7),
797 ast::BlockCheckMode::Default => String::new(),
801 fn rewrite_single_line_block(
802 context: &RewriteContext,
806 ) -> Option<String> {
807 if is_simple_block(block, context.codemap) {
808 let expr_shape = Shape::legacy(shape.width - prefix.len(), shape.indent);
809 let expr_str = try_opt!(block.stmts[0].rewrite(context, expr_shape));
810 let result = format!("{}{{ {} }}", prefix, expr_str);
811 if result.len() <= shape.width && !result.contains('\n') {
818 fn rewrite_block_with_visitor(
819 context: &RewriteContext,
823 ) -> Option<String> {
824 if let rw @ Some(_) = rewrite_empty_block(context, block, shape) {
828 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
829 visitor.block_indent = shape.indent;
830 visitor.is_if_else_block = context.is_if_else_block;
832 ast::BlockCheckMode::Unsafe(..) => {
833 let snippet = context.snippet(block.span);
834 let open_pos = try_opt!(snippet.find_uncommented("{"));
835 visitor.last_pos = block.span.lo + BytePos(open_pos as u32)
837 ast::BlockCheckMode::Default => visitor.last_pos = block.span.lo,
840 visitor.visit_block(block, None);
841 Some(format!("{}{}", prefix, visitor.buffer))
844 impl Rewrite for ast::Block {
845 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
846 // shape.width is used only for the single line case: either the empty block `{}`,
847 // or an unsafe expression `unsafe { e }`.
848 if let rw @ Some(_) = rewrite_empty_block(context, self, shape) {
852 let prefix = try_opt!(block_prefix(context, self, shape));
853 if let rw @ Some(_) = rewrite_single_line_block(context, &prefix, self, shape) {
857 rewrite_block_with_visitor(context, &prefix, self, shape)
861 impl Rewrite for ast::Stmt {
862 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
863 skip_out_of_file_lines_range!(context, self.span());
865 let result = match self.node {
866 ast::StmtKind::Local(ref local) => local.rewrite(context, shape),
867 ast::StmtKind::Expr(ref ex) | ast::StmtKind::Semi(ref ex) => {
868 let suffix = if semicolon_for_stmt(context, self) {
877 ast::StmtKind::Expr(_) => ExprType::SubExpression,
878 ast::StmtKind::Semi(_) => ExprType::Statement,
882 try_opt!(shape.sub_width(suffix.len())),
883 ).map(|s| s + suffix)
885 ast::StmtKind::Mac(..) | ast::StmtKind::Item(..) => None,
887 result.and_then(|res| {
888 recover_comment_removed(res, self.span(), context, shape)
893 // Rewrite condition if the given expression has one.
894 fn rewrite_cond(context: &RewriteContext, expr: &ast::Expr, shape: Shape) -> Option<String> {
896 ast::ExprKind::Match(ref cond, _) => {
898 let cond_shape = match context.config.control_style() {
899 Style::Legacy => try_opt!(shape.shrink_left(6).and_then(|s| s.sub_width(2))),
900 Style::Rfc => try_opt!(shape.offset_left(8)),
902 cond.rewrite(context, cond_shape)
904 ast::ExprKind::Block(ref block) if block.stmts.len() == 1 => {
905 stmt_expr(&block.stmts[0]).and_then(|e| rewrite_cond(context, e, shape))
907 _ => to_control_flow(expr, ExprType::SubExpression).and_then(|control_flow| {
909 String::from("\n") + &shape.indent.block_only().to_string(context.config);
911 .rewrite_cond(context, shape, &alt_block_sep)
912 .and_then(|rw| Some(rw.0))
917 // Abstraction over control flow expressions
919 struct ControlFlow<'a> {
920 cond: Option<&'a ast::Expr>,
921 block: &'a ast::Block,
922 else_block: Option<&'a ast::Expr>,
923 label: Option<ast::SpannedIdent>,
924 pat: Option<&'a ast::Pat>,
928 allow_single_line: bool,
929 // True if this is an `if` expression in an `else if` :-( hacky
934 fn to_control_flow<'a>(expr: &'a ast::Expr, expr_type: ExprType) -> Option<ControlFlow<'a>> {
936 ast::ExprKind::If(ref cond, ref if_block, ref else_block) => Some(ControlFlow::new_if(
940 else_block.as_ref().map(|e| &**e),
941 expr_type == ExprType::SubExpression,
945 ast::ExprKind::IfLet(ref pat, ref cond, ref if_block, ref else_block) => {
946 Some(ControlFlow::new_if(
950 else_block.as_ref().map(|e| &**e),
951 expr_type == ExprType::SubExpression,
956 ast::ExprKind::ForLoop(ref pat, ref cond, ref block, label) => {
957 Some(ControlFlow::new_for(pat, cond, block, label, expr.span))
959 ast::ExprKind::Loop(ref block, label) => {
960 Some(ControlFlow::new_loop(block, label, expr.span))
962 ast::ExprKind::While(ref cond, ref block, label) => {
963 Some(ControlFlow::new_while(None, cond, block, label, expr.span))
965 ast::ExprKind::WhileLet(ref pat, ref cond, ref block, label) => Some(
966 ControlFlow::new_while(Some(pat), cond, block, label, expr.span),
972 impl<'a> ControlFlow<'a> {
975 pat: Option<&'a ast::Pat>,
976 block: &'a ast::Block,
977 else_block: Option<&'a ast::Expr>,
978 allow_single_line: bool,
981 ) -> ControlFlow<'a> {
985 else_block: else_block,
994 allow_single_line: allow_single_line,
995 nested_if: nested_if,
1001 block: &'a ast::Block,
1002 label: Option<ast::SpannedIdent>,
1004 ) -> ControlFlow<'a> {
1014 allow_single_line: false,
1021 pat: Option<&'a ast::Pat>,
1022 cond: &'a ast::Expr,
1023 block: &'a ast::Block,
1024 label: Option<ast::SpannedIdent>,
1026 ) -> ControlFlow<'a> {
1034 matcher: match pat {
1039 allow_single_line: false,
1047 cond: &'a ast::Expr,
1048 block: &'a ast::Block,
1049 label: Option<ast::SpannedIdent>,
1051 ) -> ControlFlow<'a> {
1061 allow_single_line: false,
1067 fn rewrite_single_line(
1070 context: &RewriteContext,
1072 ) -> Option<String> {
1073 assert!(self.allow_single_line);
1074 let else_block = try_opt!(self.else_block);
1075 let fixed_cost = self.keyword.len() + " { } else { }".len();
1077 if let ast::ExprKind::Block(ref else_node) = else_block.node {
1078 if !is_simple_block(self.block, context.codemap) ||
1079 !is_simple_block(else_node, context.codemap) ||
1080 pat_expr_str.contains('\n')
1085 let new_width = try_opt!(width.checked_sub(pat_expr_str.len() + fixed_cost));
1086 let expr = &self.block.stmts[0];
1087 let if_str = try_opt!(expr.rewrite(context, Shape::legacy(new_width, Indent::empty())));
1089 let new_width = try_opt!(new_width.checked_sub(if_str.len()));
1090 let else_expr = &else_node.stmts[0];
1092 try_opt!(else_expr.rewrite(context, Shape::legacy(new_width, Indent::empty())));
1094 if if_str.contains('\n') || else_str.contains('\n') {
1098 let result = format!(
1099 "{} {} {{ {} }} else {{ {} }}",
1106 if result.len() <= width {
1107 return Some(result);
1115 impl<'a> ControlFlow<'a> {
1118 context: &RewriteContext,
1120 alt_block_sep: &str,
1121 ) -> Option<(String, usize)> {
1122 // Do not take the rhs overhead from the upper expressions into account
1123 // when rewriting pattern.
1124 let new_width = context
1127 .checked_sub(shape.used_width())
1129 let fresh_shape = Shape {
1133 let constr_shape = if self.nested_if {
1134 // We are part of an if-elseif-else chain. Our constraints are tightened.
1135 // 7 = "} else " .len()
1136 try_opt!(fresh_shape.offset_left(7))
1141 let label_string = rewrite_label(self.label);
1142 // 1 = space after keyword.
1143 let offset = self.keyword.len() + label_string.len() + 1;
1145 let pat_expr_string = match self.cond {
1147 let cond_shape = match context.config.control_style() {
1148 Style::Legacy => try_opt!(constr_shape.shrink_left(offset)),
1149 Style::Rfc => try_opt!(constr_shape.offset_left(offset)),
1151 try_opt!(rewrite_pat_expr(
1161 None => String::new(),
1164 let brace_overhead =
1165 if context.config.control_brace_style() != ControlBraceStyle::AlwaysNextLine {
1171 let one_line_budget = context
1174 .checked_sub(constr_shape.used_width() + offset + brace_overhead)
1176 let force_newline_brace = context.config.control_style() == Style::Rfc &&
1177 (pat_expr_string.contains('\n') || pat_expr_string.len() > one_line_budget) &&
1178 !last_line_extendable(&pat_expr_string);
1180 // Try to format if-else on single line.
1181 if self.allow_single_line && context.config.single_line_if_else_max_width() > 0 {
1182 let trial = self.rewrite_single_line(&pat_expr_string, context, shape.width);
1184 if let Some(cond_str) = trial {
1185 if cond_str.len() <= context.config.single_line_if_else_max_width() {
1186 return Some((cond_str, 0));
1191 let cond_span = if let Some(cond) = self.cond {
1194 mk_sp(self.block.span.lo, self.block.span.lo)
1197 // for event in event
1198 let between_kwd_cond = mk_sp(
1199 context.codemap.span_after(self.span, self.keyword.trim()),
1201 .map_or(cond_span.lo, |p| if self.matcher.is_empty() {
1204 context.codemap.span_before(self.span, self.matcher.trim())
1208 let between_kwd_cond_comment = extract_comment(between_kwd_cond, context, shape);
1210 let after_cond_comment =
1211 extract_comment(mk_sp(cond_span.hi, self.block.span.lo), context, shape);
1213 let block_sep = if self.cond.is_none() && between_kwd_cond_comment.is_some() {
1215 } else if context.config.control_brace_style() == ControlBraceStyle::AlwaysNextLine ||
1223 let used_width = if pat_expr_string.contains('\n') {
1224 last_line_width(&pat_expr_string)
1226 // 2 = spaces after keyword and condition.
1227 label_string.len() + self.keyword.len() + pat_expr_string.len() + 2
1235 between_kwd_cond_comment.as_ref().map_or(
1236 if pat_expr_string.is_empty() || pat_expr_string.starts_with('\n') {
1244 after_cond_comment.as_ref().map_or(block_sep, |s| &**s)
1251 impl<'a> Rewrite for ControlFlow<'a> {
1252 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1253 debug!("ControlFlow::rewrite {:?} {:?}", self, shape);
1256 String::from("\n") + &shape.indent.block_only().to_string(context.config);
1257 let (cond_str, used_width) = try_opt!(self.rewrite_cond(context, shape, &alt_block_sep));
1258 // If `used_width` is 0, it indicates that whole control flow is written in a single line.
1259 if used_width == 0 {
1260 return Some(cond_str);
1263 let block_width = shape.width.checked_sub(used_width).unwrap_or(0);
1264 // This is used only for the empty block case: `{}`. So, we use 1 if we know
1265 // we should avoid the single line case.
1266 let block_width = if self.else_block.is_some() || self.nested_if {
1271 let block_shape = Shape {
1275 let mut block_context = context.clone();
1276 block_context.is_if_else_block = self.else_block.is_some();
1277 let block_str = try_opt!(rewrite_block_with_visitor(
1284 let mut result = format!("{}{}", cond_str, block_str);
1286 if let Some(else_block) = self.else_block {
1287 let shape = Shape::indented(shape.indent, context.config);
1288 let mut last_in_chain = false;
1289 let rewrite = match else_block.node {
1290 // If the else expression is another if-else expression, prevent it
1291 // from being formatted on a single line.
1292 // Note how we're passing the original shape, as the
1293 // cost of "else" should not cascade.
1294 ast::ExprKind::IfLet(ref pat, ref cond, ref if_block, ref next_else_block) => {
1295 ControlFlow::new_if(
1299 next_else_block.as_ref().map(|e| &**e),
1302 mk_sp(else_block.span.lo, self.span.hi),
1303 ).rewrite(context, shape)
1305 ast::ExprKind::If(ref cond, ref if_block, ref next_else_block) => {
1306 ControlFlow::new_if(
1310 next_else_block.as_ref().map(|e| &**e),
1313 mk_sp(else_block.span.lo, self.span.hi),
1314 ).rewrite(context, shape)
1317 last_in_chain = true;
1318 // When rewriting a block, the width is only used for single line
1319 // blocks, passing 1 lets us avoid that.
1320 let else_shape = Shape {
1321 width: min(1, shape.width),
1324 format_expr(else_block, ExprType::Statement, context, else_shape)
1328 let between_kwd_else_block = mk_sp(
1332 .span_before(mk_sp(self.block.span.hi, else_block.span.lo), "else"),
1334 let between_kwd_else_block_comment =
1335 extract_comment(between_kwd_else_block, context, shape);
1337 let after_else = mk_sp(
1340 .span_after(mk_sp(self.block.span.hi, else_block.span.lo), "else"),
1343 let after_else_comment = extract_comment(after_else, context, shape);
1345 let between_sep = match context.config.control_brace_style() {
1346 ControlBraceStyle::AlwaysNextLine | ControlBraceStyle::ClosingNextLine => {
1349 ControlBraceStyle::AlwaysSameLine => " ",
1351 let after_sep = match context.config.control_brace_style() {
1352 ControlBraceStyle::AlwaysNextLine if last_in_chain => &*alt_block_sep,
1359 between_kwd_else_block_comment
1361 .map_or(between_sep, |s| &**s),
1362 after_else_comment.as_ref().map_or(after_sep, |s| &**s)
1365 result.push_str(&try_opt!(rewrite));
1372 fn rewrite_label(label: Option<ast::SpannedIdent>) -> String {
1374 Some(ident) => format!("{}: ", ident.node),
1375 None => "".to_owned(),
1379 fn extract_comment(span: Span, context: &RewriteContext, shape: Shape) -> Option<String> {
1380 let comment_str = context.snippet(span);
1381 if contains_comment(&comment_str) {
1382 let comment = try_opt!(rewrite_comment(
1389 "\n{indent}{}\n{indent}",
1391 indent = shape.indent.to_string(context.config)
1398 fn block_contains_comment(block: &ast::Block, codemap: &CodeMap) -> bool {
1399 let snippet = codemap.span_to_snippet(block.span).unwrap();
1400 contains_comment(&snippet)
1403 // Checks that a block contains no statements, an expression and no comments.
1404 // FIXME: incorrectly returns false when comment is contained completely within
1406 pub fn is_simple_block(block: &ast::Block, codemap: &CodeMap) -> bool {
1407 (block.stmts.len() == 1 && stmt_is_expr(&block.stmts[0]) &&
1408 !block_contains_comment(block, codemap))
1411 /// Checks whether a block contains at most one statement or expression, and no comments.
1412 pub fn is_simple_block_stmt(block: &ast::Block, codemap: &CodeMap) -> bool {
1413 block.stmts.len() <= 1 && !block_contains_comment(block, codemap)
1416 /// Checks whether a block contains no statements, expressions, or comments.
1417 pub fn is_empty_block(block: &ast::Block, codemap: &CodeMap) -> bool {
1418 block.stmts.is_empty() && !block_contains_comment(block, codemap)
1421 pub fn stmt_is_expr(stmt: &ast::Stmt) -> bool {
1423 ast::StmtKind::Expr(..) => true,
1428 fn is_unsafe_block(block: &ast::Block) -> bool {
1429 if let ast::BlockCheckMode::Unsafe(..) = block.rules {
1436 // inter-match-arm-comment-rules:
1437 // - all comments following a match arm before the start of the next arm
1438 // are about the second arm
1439 fn rewrite_match_arm_comment(
1440 context: &RewriteContext,
1443 arm_indent_str: &str,
1444 ) -> Option<String> {
1445 // The leading "," is not part of the arm-comment
1446 let missed_str = match missed_str.find_uncommented(",") {
1447 Some(n) => &missed_str[n + 1..],
1448 None => &missed_str[..],
1451 let mut result = String::new();
1452 // any text not preceeded by a newline is pushed unmodified to the block
1453 let first_brk = missed_str.find(|c: char| c == '\n').unwrap_or(0);
1454 result.push_str(&missed_str[..first_brk]);
1455 let missed_str = &missed_str[first_brk..]; // If missed_str had one newline, it starts with it
1457 let first = missed_str
1458 .find(|c: char| !c.is_whitespace())
1459 .unwrap_or(missed_str.len());
1460 if missed_str[..first].chars().filter(|c| c == &'\n').count() >= 2 {
1461 // Excessive vertical whitespace before comment should be preserved
1462 // FIXME handle vertical whitespace better
1465 let missed_str = missed_str[first..].trim();
1466 if !missed_str.is_empty() {
1467 let comment = try_opt!(rewrite_comment(&missed_str, false, shape, context.config));
1469 result.push_str(arm_indent_str);
1470 result.push_str(&comment);
1477 context: &RewriteContext,
1482 attrs: &[ast::Attribute],
1483 ) -> Option<String> {
1484 if arms.is_empty() {
1488 // Do not take the rhs overhead from the upper expressions into account
1489 // when rewriting match condition.
1490 let new_width = try_opt!(context.config.max_width().checked_sub(shape.used_width()));
1491 let cond_shape = Shape {
1496 let cond_shape = match context.config.control_style() {
1497 Style::Legacy => try_opt!(cond_shape.shrink_left(6)),
1498 Style::Rfc => try_opt!(cond_shape.offset_left(6)),
1500 let cond_str = try_opt!(cond.rewrite(context, cond_shape));
1501 let alt_block_sep = String::from("\n") + &shape.indent.block_only().to_string(context.config);
1502 let block_sep = match context.config.control_brace_style() {
1503 ControlBraceStyle::AlwaysNextLine => &alt_block_sep,
1504 _ if last_line_extendable(&cond_str) => " ",
1506 _ if cond_str.contains('\n') || cond_str.len() + 2 > cond_shape.width => &alt_block_sep,
1510 let nested_indent_str = shape
1512 .block_indent(context.config)
1513 .to_string(context.config);
1514 // Inner attributes.
1515 let inner_attrs = &inner_attributes(attrs);
1516 let inner_attrs_str = if inner_attrs.is_empty() {
1521 .rewrite(context, shape)
1522 .map(|s| format!("\n{}{}", nested_indent_str, s))
1526 let open_brace_pos = if inner_attrs.is_empty() {
1529 .span_after(mk_sp(cond.span.hi, arms[0].span().lo), "{")
1531 inner_attrs[inner_attrs.len() - 1].span().hi
1535 "match {}{}{{{}{}\n{}}}",
1539 try_opt!(rewrite_match_arms(
1546 shape.indent.to_string(context.config),
1550 fn arm_comma(config: &Config, body: &ast::Expr) -> &'static str {
1551 if config.match_block_trailing_comma() {
1553 } else if let ast::ExprKind::Block(ref block) = body.node {
1554 if let ast::BlockCheckMode::Default = block.rules {
1564 fn rewrite_match_arms(
1565 context: &RewriteContext,
1569 open_brace_pos: BytePos,
1570 ) -> Option<String> {
1571 let mut result = String::new();
1573 let arm_shape = if context.config.indent_match_arms() {
1574 shape.block_indent(context.config.tab_spaces())
1576 shape.block_indent(0)
1577 }.with_max_width(context.config);
1578 let arm_indent_str = arm_shape.indent.to_string(context.config);
1580 let arm_num = arms.len();
1581 for (i, arm) in arms.iter().enumerate() {
1582 // Make sure we get the stuff between arms.
1583 let missed_str = if i == 0 {
1584 context.snippet(mk_sp(open_brace_pos, arm.span().lo))
1586 context.snippet(mk_sp(arms[i - 1].span().hi, arm.span().lo))
1588 let comment = try_opt!(rewrite_match_arm_comment(
1594 if !comment.chars().all(|c| c == ' ') {
1595 result.push_str(&comment);
1598 result.push_str(&arm_indent_str);
1600 let arm_str = rewrite_match_arm(context, arm, arm_shape);
1601 if let Some(ref arm_str) = arm_str {
1602 // Trim the trailing comma if necessary.
1603 if i == arm_num - 1 && context.config.trailing_comma() == SeparatorTactic::Never &&
1604 arm_str.ends_with(',')
1606 result.push_str(&arm_str[0..arm_str.len() - 1])
1608 result.push_str(arm_str)
1611 // We couldn't format the arm, just reproduce the source.
1612 let snippet = context.snippet(arm.span());
1613 result.push_str(&snippet);
1614 if context.config.trailing_comma() != SeparatorTactic::Never {
1615 result.push_str(arm_comma(context.config, &arm.body))
1619 // BytePos(1) = closing match brace.
1620 let last_span = mk_sp(arms[arms.len() - 1].span().hi, span.hi - BytePos(1));
1621 let last_comment = context.snippet(last_span);
1622 let comment = try_opt!(rewrite_match_arm_comment(
1628 result.push_str(&comment);
1633 fn rewrite_match_arm(context: &RewriteContext, arm: &ast::Arm, shape: Shape) -> Option<String> {
1634 let attr_str = if !arm.attrs.is_empty() {
1635 if contains_skip(&arm.attrs) {
1640 try_opt!(arm.attrs.rewrite(context, shape)),
1641 shape.indent.to_string(context.config)
1646 let pats_str = try_opt!(rewrite_match_pattern(context, &arm.pats, &arm.guard, shape));
1647 let pats_str = attr_str + &pats_str;
1648 rewrite_match_body(context, &arm.body, &pats_str, shape, arm.guard.is_some())
1651 fn rewrite_match_pattern(
1652 context: &RewriteContext,
1653 pats: &Vec<ptr::P<ast::Pat>>,
1654 guard: &Option<ptr::P<ast::Expr>>,
1656 ) -> Option<String> {
1659 let pat_shape = try_opt!(shape.sub_width(5));
1661 let pat_strs = try_opt!(
1663 .map(|p| p.rewrite(context, pat_shape))
1664 .collect::<Option<Vec<_>>>()
1667 let items: Vec<_> = pat_strs.into_iter().map(ListItem::from_str).collect();
1668 let tactic = definitive_tactic(
1670 ListTactic::HorizontalVertical,
1671 Separator::VerticalBar,
1674 let fmt = ListFormatting {
1677 trailing_separator: SeparatorTactic::Never,
1679 ends_with_newline: false,
1680 preserve_newline: false,
1681 config: context.config,
1683 let pats_str = try_opt!(write_list(&items, &fmt));
1686 let guard_str = try_opt!(rewrite_guard(
1690 trimmed_last_line_width(&pats_str),
1693 Some(format!("{}{}", pats_str, guard_str))
1696 fn rewrite_match_body(
1697 context: &RewriteContext,
1698 body: &ptr::P<ast::Expr>,
1702 ) -> Option<String> {
1703 let (extend, body) = match body.node {
1704 ast::ExprKind::Block(ref block)
1705 if !is_unsafe_block(block) && is_simple_block(block, context.codemap) =>
1707 if let ast::StmtKind::Expr(ref expr) = block.stmts[0].node {
1708 (expr.can_be_overflowed(context, 1), &**expr)
1713 _ => (body.can_be_overflowed(context, 1), &**body),
1716 let comma = arm_comma(&context.config, body);
1717 let alt_block_sep = String::from("\n") + &shape.indent.block_only().to_string(context.config);
1718 let alt_block_sep = alt_block_sep.as_str();
1719 let (is_block, is_empty_block) = if let ast::ExprKind::Block(ref block) = body.node {
1720 (true, is_empty_block(block, context.codemap))
1725 let combine_orig_body = |body_str: &str| {
1726 let block_sep = match context.config.control_brace_style() {
1727 ControlBraceStyle::AlwaysNextLine if is_block => alt_block_sep,
1731 Some(format!("{} =>{}{}{}", pats_str, block_sep, body_str, comma))
1734 let forbid_same_line = has_guard && pats_str.contains('\n') && !is_empty_block;
1735 let next_line_indent = if is_block {
1738 shape.indent.block_indent(context.config)
1740 let combine_next_line_body = |body_str: &str| {
1742 return Some(format!(
1745 next_line_indent.to_string(context.config),
1750 let indent_str = shape.indent.to_string(context.config);
1751 let nested_indent_str = next_line_indent.to_string(context.config);
1752 let (body_prefix, body_suffix) = if context.config.wrap_match_arms() {
1753 let comma = if context.config.match_block_trailing_comma() {
1758 ("{", format!("\n{}}}{}", indent_str, comma))
1760 ("", String::from(","))
1763 let block_sep = match context.config.control_brace_style() {
1764 ControlBraceStyle::AlwaysNextLine => format!("{}{}\n", alt_block_sep, body_prefix),
1765 _ if body_prefix.is_empty() => "\n".to_owned(),
1766 _ if forbid_same_line => format!("{}{}\n", alt_block_sep, body_prefix),
1767 _ => format!(" {}\n", body_prefix),
1768 } + &nested_indent_str;
1779 // Let's try and get the arm body on the same line as the condition.
1781 let orig_body_shape = shape
1782 .offset_left(extra_offset(&pats_str, shape) + 4)
1783 .and_then(|shape| shape.sub_width(comma.len()));
1784 let orig_body = if let Some(body_shape) = orig_body_shape {
1785 let rewrite = nop_block_collapse(
1786 format_expr(body, ExprType::Statement, context, body_shape),
1792 if !forbid_same_line &&
1794 (!body_str.contains('\n') && body_str.len() <= body_shape.width)) =>
1796 return combine_orig_body(body_str);
1803 let orig_budget = orig_body_shape.map_or(0, |shape| shape.width);
1805 // Try putting body on the next line and see if it looks better.
1806 let next_line_body_shape = Shape::indented(next_line_indent, context.config);
1807 let next_line_body = nop_block_collapse(
1808 format_expr(body, ExprType::Statement, context, next_line_body_shape),
1809 next_line_body_shape.width,
1811 match (orig_body, next_line_body) {
1812 (Some(ref orig_str), Some(ref next_line_str))
1813 if forbid_same_line || prefer_next_line(orig_str, next_line_str) =>
1815 combine_next_line_body(next_line_str)
1817 (Some(ref orig_str), _) if extend && first_line_width(orig_str) <= orig_budget => {
1818 combine_orig_body(orig_str)
1820 (Some(ref orig_str), Some(ref next_line_str)) if orig_str.contains('\n') => {
1821 combine_next_line_body(next_line_str)
1823 (None, Some(ref next_line_str)) => combine_next_line_body(next_line_str),
1824 (None, None) => None,
1825 (Some(ref orig_str), _) => combine_orig_body(orig_str),
1829 // The `if ...` guard on a match arm.
1831 context: &RewriteContext,
1832 guard: &Option<ptr::P<ast::Expr>>,
1834 // The amount of space used up on this line for the pattern in
1835 // the arm (excludes offset).
1836 pattern_width: usize,
1837 ) -> Option<String> {
1838 if let Some(ref guard) = *guard {
1839 // First try to fit the guard string on the same line as the pattern.
1840 // 4 = ` if `, 5 = ` => {`
1841 let cond_shape = shape
1842 .offset_left(pattern_width + 4)
1843 .and_then(|s| s.sub_width(5));
1844 if let Some(cond_shape) = cond_shape {
1845 if let Some(cond_str) = guard.rewrite(context, cond_shape) {
1846 if !cond_str.contains('\n') || pattern_width <= context.config.tab_spaces() {
1847 return Some(format!(" if {}", cond_str));
1852 // Not enough space to put the guard after the pattern, try a newline.
1853 // 3 = `if `, 5 = ` => {`
1854 let cond_shape = Shape::indented(shape.indent.block_indent(context.config), context.config)
1856 .and_then(|s| s.sub_width(5));
1857 if let Some(cond_shape) = cond_shape {
1858 if let Some(cond_str) = guard.rewrite(context, cond_shape) {
1859 return Some(format!(
1861 cond_shape.indent.to_string(context.config),
1873 fn rewrite_pat_expr(
1874 context: &RewriteContext,
1875 pat: Option<&ast::Pat>,
1878 // Connecting piece between pattern and expression,
1879 // *without* trailing space.
1883 ) -> Option<String> {
1884 debug!("rewrite_pat_expr {:?} {:?} {:?}", shape, pat, expr);
1885 if let Some(pat) = pat {
1886 let matcher = if matcher.is_empty() {
1889 format!("{} ", matcher)
1892 try_opt!(try_opt!(shape.offset_left(matcher.len())).sub_width(connector.len()));
1893 let pat_string = try_opt!(pat.rewrite(context, pat_shape));
1894 let result = format!("{}{}{}", matcher, pat_string, connector);
1895 return rewrite_assign_rhs(context, result, expr, shape);
1898 let expr_rw = expr.rewrite(context, shape);
1899 // The expression may (partially) fit on the current line.
1900 // We do not allow splitting between `if` and condition.
1901 if keyword == "if" || expr_rw.is_some() {
1905 // The expression won't fit on the current line, jump to next.
1906 let nested_shape = shape
1907 .block_indent(context.config.tab_spaces())
1908 .with_max_width(context.config);
1909 let nested_indent_str = nested_shape.indent.to_string(context.config);
1910 expr.rewrite(context, nested_shape)
1911 .map(|expr_rw| format!("\n{}{}", nested_indent_str, expr_rw))
1914 fn rewrite_string_lit(context: &RewriteContext, span: Span, shape: Shape) -> Option<String> {
1915 let string_lit = context.snippet(span);
1917 if !context.config.format_strings() && !context.config.force_format_strings() {
1922 .all(|line| line.ends_with('\\'))
1924 let new_indent = shape.visual_indent(1).indent;
1925 return Some(String::from(
1929 new_indent.to_string(context.config) + line.trim_left()
1931 .collect::<Vec<_>>()
1936 return Some(string_lit);
1940 if !context.config.force_format_strings() &&
1941 !string_requires_rewrite(context, span, &string_lit, shape)
1943 return Some(string_lit);
1946 let fmt = StringFormat {
1953 config: context.config,
1956 // Remove the quote characters.
1957 let str_lit = &string_lit[1..string_lit.len() - 1];
1959 rewrite_string(str_lit, &fmt)
1962 fn string_requires_rewrite(
1963 context: &RewriteContext,
1968 if context.codemap.lookup_char_pos(span.lo).col.0 != shape.indent.width() {
1972 for (i, line) in string.lines().enumerate() {
1974 if line.len() > shape.width {
1978 if line.len() > shape.width + shape.indent.width() {
1987 pub fn rewrite_call_with_binary_search<R>(
1988 context: &RewriteContext,
1990 args: &[&ast::Expr],
1997 let force_trailing_comma = if context.inside_macro {
1998 span_ends_with_comma(context, span)
2002 let closure = |callee_max_width| {
2003 // FIXME using byte lens instead of char lens (and probably all over the
2005 let callee_shape = Shape {
2006 width: callee_max_width,
2009 let callee_str = callee
2010 .rewrite(context, callee_shape)
2011 .ok_or(Ordering::Greater)?;
2019 context.config.fn_call_width(),
2020 force_trailing_comma,
2024 binary_search(1, shape.width, closure)
2027 pub fn rewrite_call(
2028 context: &RewriteContext,
2030 args: &[ptr::P<ast::Expr>],
2033 ) -> Option<String> {
2034 let force_trailing_comma = if context.inside_macro {
2035 span_ends_with_comma(context, span)
2042 &args.iter().map(|x| &**x).collect::<Vec<_>>(),
2045 context.config.fn_call_width(),
2046 force_trailing_comma,
2050 pub fn rewrite_call_inner<'a, T>(
2051 context: &RewriteContext,
2056 args_max_width: usize,
2057 force_trailing_comma: bool,
2058 ) -> Result<String, Ordering>
2060 T: Rewrite + Spanned + ToExpr + 'a,
2062 // 2 = `( `, 1 = `(`
2063 let paren_overhead = if context.config.spaces_within_parens() {
2068 let used_width = extra_offset(&callee_str, shape);
2069 let one_line_width = shape
2071 .checked_sub(used_width + 2 * paren_overhead)
2072 .ok_or(Ordering::Greater)?;
2074 let nested_shape = shape_from_fn_call_style(
2077 used_width + 2 * paren_overhead,
2078 used_width + paren_overhead,
2079 ).ok_or(Ordering::Greater)?;
2081 let span_lo = context.codemap.span_after(span, "(");
2082 let args_span = mk_sp(span_lo, span.hi);
2084 let (extendable, list_str) = rewrite_call_args(
2091 force_trailing_comma,
2092 ).ok_or(Ordering::Less)?;
2094 if !context.use_block_indent() && need_block_indent(&list_str, nested_shape) && !extendable {
2095 let mut new_context = context.clone();
2096 new_context.use_block = true;
2097 return rewrite_call_inner(
2104 force_trailing_comma,
2108 let args_shape = shape
2109 .sub_width(last_line_width(&callee_str))
2110 .ok_or(Ordering::Less)?;
2114 wrap_args_with_parens(context, &list_str, extendable, args_shape, nested_shape)
2118 fn need_block_indent(s: &str, shape: Shape) -> bool {
2119 s.lines().skip(1).any(|s| {
2120 s.find(|c| !char::is_whitespace(c))
2121 .map_or(false, |w| w + 1 < shape.indent.width())
2125 fn rewrite_call_args<'a, T>(
2126 context: &RewriteContext,
2130 one_line_width: usize,
2131 args_max_width: usize,
2132 force_trailing_comma: bool,
2133 ) -> Option<(bool, String)>
2135 T: Rewrite + Spanned + ToExpr + 'a,
2137 let items = itemize_list(
2141 |item| item.span().lo,
2142 |item| item.span().hi,
2143 |item| item.rewrite(context, shape),
2148 let mut item_vec: Vec<_> = items.collect();
2150 // Try letting the last argument overflow to the next line with block
2151 // indentation. If its first line fits on one line with the other arguments,
2152 // we format the function arguments horizontally.
2153 let tactic = try_overflow_last_arg(
2162 let fmt = ListFormatting {
2165 trailing_separator: if force_trailing_comma {
2166 SeparatorTactic::Always
2167 } else if context.inside_macro || !context.use_block_indent() {
2168 SeparatorTactic::Never
2170 context.config.trailing_comma()
2173 ends_with_newline: context.use_block_indent() && tactic == DefinitiveListTactic::Vertical,
2174 preserve_newline: false,
2175 config: context.config,
2178 write_list(&item_vec, &fmt).map(|args_str| {
2179 (tactic != DefinitiveListTactic::Vertical, args_str)
2183 fn try_overflow_last_arg<'a, T>(
2184 context: &RewriteContext,
2185 item_vec: &mut Vec<ListItem>,
2188 one_line_width: usize,
2189 args_max_width: usize,
2190 ) -> DefinitiveListTactic
2192 T: Rewrite + Spanned + ToExpr + 'a,
2194 let overflow_last = can_be_overflowed(&context, args);
2196 // Replace the last item with its first line to see if it fits with
2198 let placeholder = if overflow_last {
2199 let mut context = context.clone();
2200 if let Some(expr) = args[args.len() - 1].to_expr() {
2202 ast::ExprKind::MethodCall(..) => context.force_one_line_chain = true,
2206 last_arg_shape(&context, &item_vec, shape, args_max_width).and_then(|arg_shape| {
2207 rewrite_last_arg_with_overflow(&context, args, &mut item_vec[args.len() - 1], arg_shape)
2213 let mut tactic = definitive_tactic(
2215 ListTactic::LimitedHorizontalVertical(args_max_width),
2220 // Replace the stub with the full overflowing last argument if the rewrite
2221 // succeeded and its first line fits with the other arguments.
2222 match (overflow_last, tactic, placeholder) {
2223 (true, DefinitiveListTactic::Horizontal, placeholder @ Some(..)) => {
2224 item_vec[args.len() - 1].item = placeholder;
2226 _ if args.len() >= 1 => {
2227 item_vec[args.len() - 1].item = args.last()
2228 .and_then(|last_arg| last_arg.rewrite(context, shape));
2229 tactic = definitive_tactic(
2231 ListTactic::LimitedHorizontalVertical(args_max_width),
2243 context: &RewriteContext,
2244 items: &Vec<ListItem>,
2246 args_max_width: usize,
2247 ) -> Option<Shape> {
2248 let overhead = items.iter().rev().skip(1).fold(0, |acc, i| {
2249 acc + i.item.as_ref().map_or(0, |s| first_line_width(&s))
2251 let max_width = min(args_max_width, shape.width);
2252 let arg_indent = if context.use_block_indent() {
2253 shape.block().indent.block_unindent(context.config)
2255 shape.block().indent
2258 width: try_opt!(max_width.checked_sub(overhead)),
2264 // Rewriting closure which is placed at the end of the function call's arg.
2265 // Returns `None` if the reformatted closure 'looks bad'.
2266 fn rewrite_last_closure(
2267 context: &RewriteContext,
2270 ) -> Option<String> {
2271 if let ast::ExprKind::Closure(capture, ref fn_decl, ref body, _) = expr.node {
2272 let body = match body.node {
2273 ast::ExprKind::Block(ref block) if block.stmts.len() == 1 => {
2274 stmt_expr(&block.stmts[0]).unwrap_or(body)
2278 let (prefix, extra_offset) = try_opt!(rewrite_closure_fn_decl(
2286 // If the closure goes multi line before its body, do not overflow the closure.
2287 if prefix.contains('\n') {
2290 let body_shape = try_opt!(shape.offset_left(extra_offset));
2291 // When overflowing the closure which consists of a single control flow expression,
2292 // force to use block if its condition uses multi line.
2293 let is_multi_lined_cond = rewrite_cond(context, body, body_shape)
2294 .map(|cond| cond.contains('\n') || cond.len() > body_shape.width)
2296 if is_multi_lined_cond {
2297 return rewrite_closure_with_block(context, body_shape, &prefix, body);
2300 // Seems fine, just format the closure in usual manner.
2301 return expr.rewrite(context, shape);
2306 fn rewrite_last_arg_with_overflow<'a, T>(
2307 context: &RewriteContext,
2309 last_item: &mut ListItem,
2313 T: Rewrite + Spanned + ToExpr + 'a,
2315 let last_arg = args[args.len() - 1];
2316 let rewrite = if let Some(expr) = last_arg.to_expr() {
2318 // When overflowing the closure which consists of a single control flow expression,
2319 // force to use block if its condition uses multi line.
2320 ast::ExprKind::Closure(..) => {
2321 // If the argument consists of multiple closures, we do not overflow
2322 // the last closure.
2323 if args.len() > 1 &&
2327 .filter_map(|arg| arg.to_expr())
2328 .any(|expr| match expr.node {
2329 ast::ExprKind::Closure(..) => true,
2334 rewrite_last_closure(context, expr, shape)
2337 _ => expr.rewrite(context, shape),
2340 last_arg.rewrite(context, shape)
2343 if let Some(rewrite) = rewrite {
2344 let rewrite_first_line = Some(rewrite[..first_line_width(&rewrite)].to_owned());
2345 last_item.item = rewrite_first_line;
2352 fn can_be_overflowed<'a, T>(context: &RewriteContext, args: &[&T]) -> bool
2354 T: Rewrite + Spanned + ToExpr + 'a,
2357 .map_or(false, |x| x.can_be_overflowed(context, args.len()))
2360 pub fn can_be_overflowed_expr(context: &RewriteContext, expr: &ast::Expr, args_len: usize) -> bool {
2362 ast::ExprKind::Match(..) => {
2363 (context.use_block_indent() && args_len == 1) ||
2364 (context.config.fn_call_style() == IndentStyle::Visual && args_len > 1)
2366 ast::ExprKind::If(..) |
2367 ast::ExprKind::IfLet(..) |
2368 ast::ExprKind::ForLoop(..) |
2369 ast::ExprKind::Loop(..) |
2370 ast::ExprKind::While(..) |
2371 ast::ExprKind::WhileLet(..) => {
2372 context.config.combine_control_expr() && context.use_block_indent() && args_len == 1
2374 ast::ExprKind::Block(..) | ast::ExprKind::Closure(..) => {
2375 context.use_block_indent() ||
2376 context.config.fn_call_style() == IndentStyle::Visual && args_len > 1
2378 ast::ExprKind::Array(..) |
2379 ast::ExprKind::Call(..) |
2380 ast::ExprKind::Mac(..) |
2381 ast::ExprKind::MethodCall(..) |
2382 ast::ExprKind::Struct(..) |
2383 ast::ExprKind::Tup(..) => context.use_block_indent() && args_len == 1,
2384 ast::ExprKind::AddrOf(_, ref expr) |
2385 ast::ExprKind::Box(ref expr) |
2386 ast::ExprKind::Try(ref expr) |
2387 ast::ExprKind::Unary(_, ref expr) |
2388 ast::ExprKind::Cast(ref expr, _) => can_be_overflowed_expr(context, expr, args_len),
2393 pub fn wrap_args_with_parens(
2394 context: &RewriteContext,
2396 is_extendable: bool,
2398 nested_shape: Shape,
2400 if !context.use_block_indent() ||
2401 (context.inside_macro && !args_str.contains('\n') &&
2402 args_str.len() + paren_overhead(context) <= shape.width) || is_extendable
2404 if context.config.spaces_within_parens() && args_str.len() > 0 {
2405 format!("( {} )", args_str)
2407 format!("({})", args_str)
2412 nested_shape.indent.to_string(context.config),
2414 shape.block().indent.to_string(context.config)
2419 fn span_ends_with_comma(context: &RewriteContext, span: Span) -> bool {
2420 let snippet = context.snippet(span);
2422 .trim_right_matches(|c: char| c == ')' || c.is_whitespace())
2426 fn rewrite_paren(context: &RewriteContext, subexpr: &ast::Expr, shape: Shape) -> Option<String> {
2427 debug!("rewrite_paren, shape: {:?}", shape);
2428 let total_paren_overhead = paren_overhead(context);
2429 let paren_overhead = total_paren_overhead / 2;
2430 let sub_shape = try_opt!(
2432 .offset_left(paren_overhead)
2433 .and_then(|s| s.sub_width(paren_overhead))
2436 let paren_wrapper = |s: &str| if context.config.spaces_within_parens() && s.len() > 0 {
2437 format!("( {} )", s)
2442 let subexpr_str = try_opt!(subexpr.rewrite(context, sub_shape));
2443 debug!("rewrite_paren, subexpr_str: `{:?}`", subexpr_str);
2445 if subexpr_str.contains('\n') ||
2446 first_line_width(&subexpr_str) + total_paren_overhead <= shape.width
2448 Some(paren_wrapper(&subexpr_str))
2457 context: &RewriteContext,
2459 ) -> Option<String> {
2460 let expr_str = try_opt!(expr.rewrite(context, shape));
2462 let (lbr, rbr) = if context.config.spaces_within_square_brackets() {
2468 let offset = last_line_width(&expr_str) + lbr.len();
2469 let rhs_overhead = shape.rhs_overhead(context.config);
2470 let index_shape = if expr_str.contains('\n') {
2471 Shape::legacy(context.config.max_width(), shape.indent)
2472 .offset_left(offset)
2473 .and_then(|shape| shape.sub_width(rbr.len() + rhs_overhead))
2475 shape.visual_indent(offset).sub_width(offset + rbr.len())
2477 let orig_index_rw = index_shape.and_then(|s| index.rewrite(context, s));
2479 // Return if index fits in a single line.
2480 match orig_index_rw {
2481 Some(ref index_str) if !index_str.contains('\n') => {
2482 return Some(format!("{}{}{}{}", expr_str, lbr, index_str, rbr));
2487 // Try putting index on the next line and see if it fits in a single line.
2488 let indent = shape.indent.block_indent(context.config);
2489 let index_shape = try_opt!(Shape::indented(indent, context.config).offset_left(lbr.len()));
2490 let index_shape = try_opt!(index_shape.sub_width(rbr.len() + rhs_overhead));
2491 let new_index_rw = index.rewrite(context, index_shape);
2492 match (orig_index_rw, new_index_rw) {
2493 (_, Some(ref new_index_str)) if !new_index_str.contains('\n') => Some(format!(
2496 indent.to_string(&context.config),
2501 (None, Some(ref new_index_str)) => Some(format!(
2504 indent.to_string(&context.config),
2509 (Some(ref index_str), _) => Some(format!("{}{}{}{}", expr_str, lbr, index_str, rbr)),
2514 fn struct_lit_can_be_aligned(fields: &[ast::Field], base: &Option<&ast::Expr>) -> bool {
2519 fields.iter().all(|field| !field.is_shorthand)
2522 fn rewrite_struct_lit<'a>(
2523 context: &RewriteContext,
2525 fields: &'a [ast::Field],
2526 base: Option<&'a ast::Expr>,
2529 ) -> Option<String> {
2530 debug!("rewrite_struct_lit: shape {:?}", shape);
2532 enum StructLitField<'a> {
2533 Regular(&'a ast::Field),
2534 Base(&'a ast::Expr),
2538 let path_shape = try_opt!(shape.sub_width(2));
2539 let path_str = try_opt!(rewrite_path(
2547 if fields.len() == 0 && base.is_none() {
2548 return Some(format!("{} {{}}", path_str));
2551 // Foo { a: Foo } - indent is +3, width is -5.
2552 let (h_shape, v_shape) = try_opt!(struct_lit_shape(shape, context, path_str.len() + 3, 2));
2554 let one_line_width = h_shape.map_or(0, |shape| shape.width);
2555 let body_lo = context.codemap.span_after(span, "{");
2556 let fields_str = if struct_lit_can_be_aligned(fields, &base) &&
2557 context.config.struct_field_align_threshold() > 0
2559 try_opt!(rewrite_with_alignment(
2563 mk_sp(body_lo, span.hi),
2567 let field_iter = fields
2569 .map(StructLitField::Regular)
2570 .chain(base.into_iter().map(StructLitField::Base));
2572 let span_lo = |item: &StructLitField| match *item {
2573 StructLitField::Regular(field) => field.span().lo,
2574 StructLitField::Base(expr) => {
2575 let last_field_hi = fields.last().map_or(span.lo, |field| field.span.hi);
2576 let snippet = context.snippet(mk_sp(last_field_hi, expr.span.lo));
2577 let pos = snippet.find_uncommented("..").unwrap();
2578 last_field_hi + BytePos(pos as u32)
2581 let span_hi = |item: &StructLitField| match *item {
2582 StructLitField::Regular(field) => field.span().hi,
2583 StructLitField::Base(expr) => expr.span.hi,
2585 let rewrite = |item: &StructLitField| match *item {
2586 StructLitField::Regular(field) => {
2587 // The 1 taken from the v_budget is for the comma.
2588 rewrite_field(context, field, try_opt!(v_shape.sub_width(1)), 0)
2590 StructLitField::Base(expr) => {
2592 expr.rewrite(context, try_opt!(v_shape.offset_left(2)))
2593 .map(|s| format!("..{}", s))
2597 let items = itemize_list(
2608 let item_vec = items.collect::<Vec<_>>();
2610 let tactic = struct_lit_tactic(h_shape, context, &item_vec);
2611 let nested_shape = shape_for_tactic(tactic, h_shape, v_shape);
2612 let fmt = struct_lit_formatting(nested_shape, tactic, context, base.is_some());
2614 try_opt!(write_list(&item_vec, &fmt))
2617 let fields_str = wrap_struct_field(context, &fields_str, shape, v_shape, one_line_width);
2618 Some(format!("{} {{{}}}", path_str, fields_str))
2620 // FIXME if context.config.struct_lit_style() == Visual, but we run out
2621 // of space, we should fall back to BlockIndent.
2624 pub fn wrap_struct_field(
2625 context: &RewriteContext,
2628 nested_shape: Shape,
2629 one_line_width: usize,
2631 if context.config.struct_lit_style() == IndentStyle::Block &&
2632 (fields_str.contains('\n') ||
2633 context.config.struct_lit_multiline_style() == MultilineStyle::ForceMulti ||
2634 fields_str.len() > one_line_width)
2638 nested_shape.indent.to_string(context.config),
2640 shape.indent.to_string(context.config)
2643 // One liner or visual indent.
2644 format!(" {} ", fields_str)
2648 pub fn struct_lit_field_separator(config: &Config) -> &str {
2650 config.space_before_struct_lit_field_colon(),
2651 config.space_after_struct_lit_field_colon(),
2655 pub fn rewrite_field(
2656 context: &RewriteContext,
2659 prefix_max_width: usize,
2660 ) -> Option<String> {
2661 if contains_skip(&field.attrs) {
2663 context.snippet(field.span()),
2664 context.config.max_width(),
2668 let name = &field.ident.node.to_string();
2669 if field.is_shorthand {
2670 Some(name.to_string())
2672 let mut separator = String::from(struct_lit_field_separator(context.config));
2673 for _ in 0..prefix_max_width.checked_sub(name.len()).unwrap_or(0) {
2674 separator.push(' ');
2676 let overhead = name.len() + separator.len();
2677 let expr_shape = try_opt!(shape.offset_left(overhead));
2678 let expr = field.expr.rewrite(context, expr_shape);
2680 let mut attrs_str = try_opt!(field.attrs.rewrite(context, shape));
2681 if !attrs_str.is_empty() {
2682 attrs_str.push_str(&format!("\n{}", shape.indent.to_string(context.config)));
2686 Some(e) => Some(format!("{}{}{}{}", attrs_str, name, separator, e)),
2688 let expr_offset = shape.indent.block_indent(context.config);
2691 .rewrite(context, Shape::indented(expr_offset, context.config));
2697 expr_offset.to_string(&context.config),
2706 fn shape_from_fn_call_style(
2707 context: &RewriteContext,
2711 ) -> Option<Shape> {
2712 if context.use_block_indent() {
2716 .block_indent(context.config.tab_spaces())
2717 .with_max_width(context.config)
2720 shape.visual_indent(offset).sub_width(overhead)
2724 fn rewrite_tuple_in_visual_indent_style<'a, T>(
2725 context: &RewriteContext,
2731 T: Rewrite + Spanned + ToExpr + 'a,
2733 let mut items = items.iter();
2734 // In case of length 1, need a trailing comma
2735 debug!("rewrite_tuple_in_visual_indent_style {:?}", shape);
2736 if items.len() == 1 {
2738 let nested_shape = try_opt!(shape.sub_width(3)).visual_indent(1);
2739 return items.next().unwrap().rewrite(context, nested_shape).map(
2740 |s| if context.config.spaces_within_parens() {
2741 format!("( {}, )", s)
2748 let list_lo = context.codemap.span_after(span, "(");
2749 let nested_shape = try_opt!(shape.sub_width(2)).visual_indent(1);
2750 let items = itemize_list(
2754 |item| item.span().lo,
2755 |item| item.span().hi,
2756 |item| item.rewrite(context, nested_shape),
2758 span.hi - BytePos(1),
2761 let item_vec: Vec<_> = items.collect();
2762 let tactic = definitive_tactic(
2764 ListTactic::HorizontalVertical,
2768 let fmt = ListFormatting {
2771 trailing_separator: SeparatorTactic::Never,
2773 ends_with_newline: false,
2774 preserve_newline: false,
2775 config: context.config,
2777 let list_str = try_opt!(write_list(&item_vec, &fmt));
2779 if context.config.spaces_within_parens() && list_str.len() > 0 {
2780 Some(format!("( {} )", list_str))
2782 Some(format!("({})", list_str))
2786 pub fn rewrite_tuple<'a, T>(
2787 context: &RewriteContext,
2793 T: Rewrite + Spanned + ToExpr + 'a,
2795 debug!("rewrite_tuple {:?}", shape);
2796 if context.use_block_indent() {
2797 // We use the same rule as funcation call for rewriting tuple.
2798 let force_trailing_comma = if context.inside_macro {
2799 span_ends_with_comma(context, span)
2809 context.config.fn_call_width(),
2810 force_trailing_comma,
2813 rewrite_tuple_in_visual_indent_style(context, items, span, shape)
2817 pub fn rewrite_unary_prefix<R: Rewrite>(
2818 context: &RewriteContext,
2822 ) -> Option<String> {
2824 .rewrite(context, try_opt!(shape.offset_left(prefix.len())))
2825 .map(|r| format!("{}{}", prefix, r))
2828 // FIXME: this is probably not correct for multi-line Rewrites. we should
2829 // subtract suffix.len() from the last line budget, not the first!
2830 pub fn rewrite_unary_suffix<R: Rewrite>(
2831 context: &RewriteContext,
2835 ) -> Option<String> {
2837 .rewrite(context, try_opt!(shape.sub_width(suffix.len())))
2844 fn rewrite_unary_op(
2845 context: &RewriteContext,
2849 ) -> Option<String> {
2850 // For some reason, an UnOp is not spanned like BinOp!
2851 let operator_str = match *op {
2852 ast::UnOp::Deref => "*",
2853 ast::UnOp::Not => "!",
2854 ast::UnOp::Neg => "-",
2856 rewrite_unary_prefix(context, operator_str, expr, shape)
2859 fn rewrite_assignment(
2860 context: &RewriteContext,
2863 op: Option<&ast::BinOp>,
2865 ) -> Option<String> {
2866 let operator_str = match op {
2867 Some(op) => context.snippet(op.span),
2868 None => "=".to_owned(),
2871 // 1 = space between lhs and operator.
2872 let lhs_shape = try_opt!(shape.sub_width(operator_str.len() + 1));
2873 let lhs_str = format!(
2875 try_opt!(lhs.rewrite(context, lhs_shape)),
2879 rewrite_assign_rhs(context, lhs_str, rhs, shape)
2882 // The left hand side must contain everything up to, and including, the
2883 // assignment operator.
2884 pub fn rewrite_assign_rhs<S: Into<String>>(
2885 context: &RewriteContext,
2889 ) -> Option<String> {
2890 let lhs = lhs.into();
2891 let last_line_width = last_line_width(&lhs) - if lhs.contains('\n') {
2892 shape.indent.width()
2896 // 1 = space between operator and rhs.
2897 let orig_shape = try_opt!(shape.offset_left(last_line_width + 1));
2898 let rhs = try_opt!(choose_rhs(
2902 ex.rewrite(context, orig_shape)
2908 context: &RewriteContext,
2911 orig_rhs: Option<String>,
2912 ) -> Option<String> {
2914 Some(ref new_str) if !new_str.contains('\n') => Some(format!(" {}", new_str)),
2916 // Expression did not fit on the same line as the identifier.
2917 // Try splitting the line and see if that works better.
2918 let new_shape = try_opt!(
2920 shape.block().indent.block_indent(context.config),
2922 ).sub_width(shape.rhs_overhead(context.config))
2924 let new_rhs = expr.rewrite(context, new_shape);
2925 let new_indent_str = &new_shape.indent.to_string(context.config);
2927 match (orig_rhs, new_rhs) {
2928 (Some(ref orig_rhs), Some(ref new_rhs)) if prefer_next_line(orig_rhs, new_rhs) => {
2929 Some(format!("\n{}{}", new_indent_str, new_rhs))
2931 (None, Some(ref new_rhs)) => Some(format!("\n{}{}", new_indent_str, new_rhs)),
2932 (None, None) => None,
2933 (Some(ref orig_rhs), _) => Some(format!(" {}", orig_rhs)),
2939 fn prefer_next_line(orig_rhs: &str, next_line_rhs: &str) -> bool {
2940 fn count_line_breaks(src: &str) -> usize {
2941 src.chars().filter(|&x| x == '\n').count()
2944 !next_line_rhs.contains('\n') ||
2945 count_line_breaks(orig_rhs) > count_line_breaks(next_line_rhs) + 1
2948 fn rewrite_expr_addrof(
2949 context: &RewriteContext,
2950 mutability: ast::Mutability,
2953 ) -> Option<String> {
2954 let operator_str = match mutability {
2955 ast::Mutability::Immutable => "&",
2956 ast::Mutability::Mutable => "&mut ",
2958 rewrite_unary_prefix(context, operator_str, expr, shape)
2962 fn to_expr(&self) -> Option<&ast::Expr>;
2963 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool;
2966 impl ToExpr for ast::Expr {
2967 fn to_expr(&self) -> Option<&ast::Expr> {
2971 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool {
2972 can_be_overflowed_expr(context, self, len)
2976 impl ToExpr for ast::Ty {
2977 fn to_expr(&self) -> Option<&ast::Expr> {
2981 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool {
2982 can_be_overflowed_type(context, self, len)
2986 impl<'a> ToExpr for TuplePatField<'a> {
2987 fn to_expr(&self) -> Option<&ast::Expr> {
2991 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool {
2992 can_be_overflowed_pat(context, self, len)
2996 impl<'a> ToExpr for ast::StructField {
2997 fn to_expr(&self) -> Option<&ast::Expr> {
3001 fn can_be_overflowed(&self, _: &RewriteContext, _: usize) -> bool {