use syntax::{ast, ptr};
use codemap::SpanUtils;
-use comment::combine_strs_with_missing_comments;
+use comment::{combine_strs_with_missing_comments, rewrite_comment};
use config::{Config, ControlBraceStyle, IndentStyle};
use expr::{
format_expr, is_empty_block, is_simple_block, is_unsafe_block, prefer_next_line,
false,
)
})?;
+
+ let arrow_span = mk_sp(arm.pats.last().unwrap().span.hi(), arm.body.span.lo());
rewrite_match_body(
context,
&arm.body,
&pats_str,
shape,
arm.guard.is_some(),
+ arrow_span,
is_last,
)
}
Some(format!("{}{}", pats_str, guard_str))
}
+fn block_can_be_flattened<'a>(
+ context: &RewriteContext,
+ expr: &'a ast::Expr,
+) -> Option<&'a ast::Block> {
+ match expr.node {
+ ast::ExprKind::Block(ref block, _)
+ if !is_unsafe_block(block)
+ && is_simple_block(block, Some(&expr.attrs), context.codemap) =>
+ {
+ Some(&*block)
+ }
+ _ => None,
+ }
+}
+
// (extend, body)
// @extend: true if the arm body can be put next to `=>`
// @body: flattened body, if the body is block with a single expression
fn flatten_arm_body<'a>(context: &'a RewriteContext, body: &'a ast::Expr) -> (bool, &'a ast::Expr) {
- match body.node {
- ast::ExprKind::Block(ref block, _)
- if !is_unsafe_block(block)
- && is_simple_block(block, Some(&body.attrs), context.codemap) =>
- {
- if let ast::StmtKind::Expr(ref expr) = block.stmts[0].node {
- (
- !context.config.force_multiline_blocks() && can_flatten_block_around_this(expr),
- &*expr,
- )
+ if let Some(ref block) = block_can_be_flattened(context, body) {
+ if let ast::StmtKind::Expr(ref expr) = block.stmts[0].node {
+ if let ast::ExprKind::Block(..) = expr.node {
+ flatten_arm_body(context, expr)
} else {
- (false, &*body)
+ let can_extend_expr =
+ !context.config.force_multiline_blocks() && can_flatten_block_around_this(expr);
+ (can_extend_expr, &*expr)
}
+ } else {
+ (false, &*body)
}
- _ => (
+ } else {
+ (
!context.config.force_multiline_blocks() && body.can_be_overflowed(context, 1),
&*body,
- ),
+ )
}
}
pats_str: &str,
shape: Shape,
has_guard: bool,
+ arrow_span: Span,
is_last: bool,
) -> Option<String> {
let (extend, body) = flatten_arm_body(context, body);
Some(format!("{} =>{}{}{}", pats_str, block_sep, body_str, comma))
};
- let forbid_same_line = has_guard && pats_str.contains('\n') && !is_empty_block;
let next_line_indent = if !is_block || is_empty_block {
shape.indent.block_indent(context.config)
} else {
shape.indent
};
+
+ let forbid_same_line = has_guard && pats_str.contains('\n') && !is_empty_block;
+
+ // Look for comments between `=>` and the start of the body.
+ let arrow_comment = {
+ let arrow_snippet = context.snippet(arrow_span).trim();
+ let arrow_index = arrow_snippet.find("=>").unwrap();
+ // 2 = `=>`
+ let comment_str = arrow_snippet[arrow_index + 2..].trim();
+ if comment_str.is_empty() {
+ String::new()
+ } else {
+ rewrite_comment(comment_str, false, shape, &context.config)?
+ }
+ };
+
let combine_next_line_body = |body_str: &str| {
+ let nested_indent_str = next_line_indent.to_string_with_newline(context.config);
+
if is_block {
- return Some(format!(
- "{} =>{}{}",
- pats_str,
- next_line_indent.to_string_with_newline(context.config),
- body_str
- ));
+ let mut result = pats_str.to_owned();
+ result.push_str(" =>");
+ if !arrow_comment.is_empty() {
+ result.push_str(&nested_indent_str);
+ result.push_str(&arrow_comment);
+ }
+ result.push_str(&nested_indent_str);
+ result.push_str(&body_str);
+ return Some(result);
}
let indent_str = shape.indent.to_string_with_newline(context.config);
- let nested_indent_str = next_line_indent.to_string_with_newline(context.config);
let (body_prefix, body_suffix) = if context.config.match_arm_blocks() {
let comma = if context.config.match_block_trailing_comma() {
","
let block_sep = match context.config.control_brace_style() {
ControlBraceStyle::AlwaysNextLine => format!("{}{}", alt_block_sep, body_prefix),
_ if body_prefix.is_empty() => "".to_owned(),
- _ if forbid_same_line => format!("{}{}", alt_block_sep, body_prefix),
+ _ if forbid_same_line || !arrow_comment.is_empty() => {
+ format!("{}{}", alt_block_sep, body_prefix)
+ }
_ => format!(" {}", body_prefix),
} + &nested_indent_str;
- Some(format!(
- "{} =>{}{}{}",
- pats_str, block_sep, body_str, body_suffix
- ))
+ let mut result = pats_str.to_owned();
+ result.push_str(" =>");
+ if !arrow_comment.is_empty() {
+ result.push_str(&indent_str);
+ result.push_str(&arrow_comment);
+ }
+ result.push_str(&block_sep);
+ result.push_str(&body_str);
+ result.push_str(&body_suffix);
+ Some(result)
};
// Let's try and get the arm body on the same line as the condition.
let orig_body_shape = shape
.offset_left(extra_offset(pats_str, shape) + 4)
.and_then(|shape| shape.sub_width(comma.len()));
- let orig_body = if let Some(body_shape) = orig_body_shape {
+ let orig_body = if forbid_same_line || !arrow_comment.is_empty() {
+ None
+ } else if let Some(body_shape) = orig_body_shape {
let rewrite = nop_block_collapse(
format_expr(body, ExprType::Statement, context, body_shape),
body_shape.width,
match rewrite {
Some(ref body_str)
- if !forbid_same_line
- && (is_block
- || (!body_str.contains('\n') && body_str.len() <= body_shape.width)) =>
+ if is_block || (!body_str.contains('\n') && body_str.len() <= body_shape.width) =>
{
return combine_orig_body(body_str);
}
);
match (orig_body, next_line_body) {
(Some(ref orig_str), Some(ref next_line_str))
- if forbid_same_line
- || prefer_next_line(orig_str, next_line_str, RhsTactics::Default) =>
+ if prefer_next_line(orig_str, next_line_str, RhsTactics::Default) =>
{
combine_next_line_body(next_line_str)
}
projects / rust.git / blobdiff