bjoernager/rust
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extract parse_index_expr & refactor parse_dot_suffix

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This commit is contained in:
Mazdak Farrokhzad 2019-12-07 00:04:46 +01:00
parent 0bb3dad5a6
commit 98701b2c61
1 changed files with 22 additions and 28 deletions
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50
src/librustc_parse/parser/expr.rs
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@ -694,7 +694,6 @@ impl<'a> Parser<'a> {
fn parse_dot_or_call_expr_with_(&mut self, e0: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
let mut e = e0;
let mut hi;
loop {
// expr?
while self.eat(&token::Question) {
@ -766,23 +765,21 @@ impl<'a> Parser<'a> {
});
e = self.recover_seq_parse_error(token::Paren, lo, seq);
}
// expr[...]
// Could be either an index expression or a slicing expression.
token::OpenDelim(token::Bracket) => {
self.bump();
let ix = self.parse_expr()?;
hi = self.token.span;
self.expect(&token::CloseDelim(token::Bracket))?;
let index = self.mk_index(e, ix);
e = self.mk_expr(lo.to(hi), index, AttrVec::new())
}
token::OpenDelim(token::Bracket) => e = self.parse_index_expr(lo, e)?,
_ => return Ok(e),
}
}
return Ok(e);
}
/// Parse an indexing expression `expr[...]`.
fn parse_index_expr(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
self.bump(); // `[`
let index = self.parse_expr()?;
self.expect(&token::CloseDelim(token::Bracket))?;
Ok(self.mk_expr(lo.to(self.prev_span), self.mk_index(base, index), AttrVec::new()))
}
/// Assuming we have just parsed `.`, continue parsing into an expression.
fn parse_dot_suffix(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
if self.token.span.rust_2018() && self.eat_keyword(kw::Await) {
@ -792,25 +789,22 @@ impl<'a> Parser<'a> {
let segment = self.parse_path_segment(PathStyle::Expr)?;
self.check_trailing_angle_brackets(&segment, token::OpenDelim(token::Paren));
Ok(match self.token.kind {
token::OpenDelim(token::Paren) => {
// Method call `expr.f()`
let mut args = self.parse_paren_expr_seq()?;
args.insert(0, self_arg);
if self.check(&token::OpenDelim(token::Paren)) {
// Method call `expr.f()`
let mut args = self.parse_paren_expr_seq()?;
args.insert(0, self_arg);
let span = lo.to(self.prev_span);
self.mk_expr(span, ExprKind::MethodCall(segment, args), AttrVec::new())
let span = lo.to(self.prev_span);
Ok(self.mk_expr(span, ExprKind::MethodCall(segment, args), AttrVec::new()))
} else {
// Field access `expr.f`
if let Some(args) = segment.args {
self.span_err(args.span(), "field expressions may not have generic arguments");
}
_ => {
// Field access `expr.f`
if let Some(args) = segment.args {
self.span_err(args.span(), "field expressions may not have generic arguments");
}
let span = lo.to(self.prev_span);
self.mk_expr(span, ExprKind::Field(self_arg, segment.ident), AttrVec::new())
}
})
let span = lo.to(self.prev_span);
Ok(self.mk_expr(span, ExprKind::Field(self_arg, segment.ident), AttrVec::new()))
}
}
/// At the bottom (top?) of the precedence hierarchy,