bjoernager/rust
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simplify parse_prefix_range_expr

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This commit is contained in:
Mazdak Farrokhzad 2019-12-07 04:37:05 +01:00
parent 8456c403e1
commit e43a7ef1d4
1 changed files with 17 additions and 22 deletions
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39
src/librustc_parse/parser/expr.rs
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@ -406,10 +406,7 @@ impl<'a> Parser<'a> {
} }
/// Parses prefix-forms of range notation: `..expr`, `..`, `..=expr`. /// Parses prefix-forms of range notation: `..expr`, `..`, `..=expr`.
fn parse_prefix_range_expr( fn parse_prefix_range_expr(&mut self, attrs: Option<AttrVec>) -> PResult<'a, P<Expr>> {
&mut self,
already_parsed_attrs: Option<AttrVec>,
) -> PResult<'a, P<Expr>> {
// Check for deprecated `...` syntax. // Check for deprecated `...` syntax.
if self.token == token::DotDotDot { if self.token == token::DotDotDot {
self.err_dotdotdot_syntax(self.token.span); self.err_dotdotdot_syntax(self.token.span);
@ -420,25 +417,23 @@ impl<'a> Parser<'a> {
"parse_prefix_range_expr: token {:?} is not DotDot/DotDotEq", "parse_prefix_range_expr: token {:?} is not DotDot/DotDotEq",
self.token self.token
); );
let tok = self.token.clone();
let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
let lo = self.token.span;
let mut hi = self.token.span;
self.bump();
let opt_end = if self.is_at_start_of_range_notation_rhs() {
// RHS must be parsed with more associativity than the dots.
let next_prec = AssocOp::from_token(&tok).unwrap().precedence() + 1;
Some(self.parse_assoc_expr_with(next_prec, LhsExpr::NotYetParsed).map(|x| {
hi = x.span;
x
})?)
} else {
None
};
let limits = if tok == token::DotDot { RangeLimits::HalfOpen } else { RangeLimits::Closed };
let r = self.mk_range(None, opt_end, limits)?; let limits = match self.token.kind {
Ok(self.mk_expr(lo.to(hi), r, attrs)) token::DotDot => RangeLimits::HalfOpen,
_ => RangeLimits::Closed,
};
let op = AssocOp::from_token(&self.token);
let attrs = self.parse_or_use_outer_attributes(attrs)?;
let lo = self.token.span;
self.bump();
let (span, opt_end) = if self.is_at_start_of_range_notation_rhs() {
// RHS must be parsed with more associativity than the dots.
self.parse_assoc_expr_with(op.unwrap().precedence() + 1, LhsExpr::NotYetParsed)
.map(|x| (lo.to(x.span), Some(x)))?
} else {
(lo, None)
};
Ok(self.mk_expr(span, self.mk_range(None, opt_end, limits)?, attrs))
} }
/// Parses a prefix-unary-operator expr. /// Parses a prefix-unary-operator expr.