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Move float breaking out of Parser::parse_expr_tuple_field_access_float

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Purely a refactor in preparation of using it in offset_of!() parsing
This commit is contained in:
est31 2023-06-02 18:51:27 +02:00
parent a77659a1e1
commit d74ec96e8d
1 changed files with 53 additions and 22 deletions
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75
compiler/rustc_parse/src/parser/expr.rs
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@ -91,6 +91,18 @@ fn from(expr: P<Expr>) -> Self {
}
}
#[derive(Debug)]
enum DestructuredFloat {
/// 1e2
Single(Symbol, Span),
/// 1.
TrailingDot(Symbol, Span, Span),
/// 1.2 | 1.2e3
MiddleDot(Symbol, Span, Span, Symbol, Span),
/// Invalid
Error,
}
impl<'a> Parser<'a> {
/// Parses an expression.
#[inline]
@ -1013,13 +1025,8 @@ fn error_unexpected_after_dot(&self) {
// support pushing "future tokens" (would be also helpful to `break_and_eat`), or
// we should break everything including floats into more basic proc-macro style
// tokens in the lexer (probably preferable).
fn parse_expr_tuple_field_access_float(
&mut self,
lo: Span,
base: P<Expr>,
float: Symbol,
suffix: Option<Symbol>,
) -> P<Expr> {
// See also `TokenKind::break_two_token_op` which does similar splitting of `>>` into `>`.
fn break_up_float(&mut self, float: Symbol) -> DestructuredFloat {
#[derive(Debug)]
enum FloatComponent {
IdentLike(String),
@ -1056,7 +1063,7 @@ enum FloatComponent {
match &*components {
// 1e2
[IdentLike(i)] => {
self.parse_expr_tuple_field_access(lo, base, Symbol::intern(&i), suffix, None)
DestructuredFloat::Single(Symbol::intern(&i), span)
}
// 1.
[IdentLike(i), Punct('.')] => {
@ -1068,11 +1075,8 @@ enum FloatComponent {
} else {
(span, span)
};
assert!(suffix.is_none());
let symbol = Symbol::intern(&i);
self.token = Token::new(token::Ident(symbol, false), ident_span);
let next_token = (Token::new(token::Dot, dot_span), self.token_spacing);
self.parse_expr_tuple_field_access(lo, base, symbol, None, Some(next_token))
DestructuredFloat::TrailingDot(symbol, ident_span, dot_span)
}
// 1.2 | 1.2e3
[IdentLike(i1), Punct('.'), IdentLike(i2)] => {
@ -1088,16 +1092,8 @@ enum FloatComponent {
(span, span, span)
};
let symbol1 = Symbol::intern(&i1);
self.token = Token::new(token::Ident(symbol1, false), ident1_span);
// This needs to be `Spacing::Alone` to prevent regressions.
// See issue #76399 and PR #76285 for more details
let next_token1 = (Token::new(token::Dot, dot_span), Spacing::Alone);
let base1 =
self.parse_expr_tuple_field_access(lo, base, symbol1, None, Some(next_token1));
let symbol2 = Symbol::intern(&i2);
let next_token2 = Token::new(token::Ident(symbol2, false), ident2_span);
self.bump_with((next_token2, self.token_spacing)); // `.`
self.parse_expr_tuple_field_access(lo, base1, symbol2, suffix, None)
DestructuredFloat::MiddleDot(symbol1, ident1_span, dot_span, symbol2, ident2_span)
}
// 1e+ | 1e- (recovered)
[IdentLike(_), Punct('+' | '-')] |
@ -1109,12 +1105,47 @@ enum FloatComponent {
[IdentLike(_), Punct('.'), IdentLike(_), Punct('+' | '-'), IdentLike(_)] => {
// See the FIXME about `TokenCursor` above.
self.error_unexpected_after_dot();
base
DestructuredFloat::Error
}
_ => panic!("unexpected components in a float token: {:?}", components),
}
}
fn parse_expr_tuple_field_access_float(
&mut self,
lo: Span,
base: P<Expr>,
float: Symbol,
suffix: Option<Symbol>,
) -> P<Expr> {
match self.break_up_float(float) {
// 1e2
DestructuredFloat::Single(sym, _sp) => {
self.parse_expr_tuple_field_access(lo, base, sym, suffix, None)
}
// 1.
DestructuredFloat::TrailingDot(sym, ident_span, dot_span) => {
assert!(suffix.is_none());
self.token = Token::new(token::Ident(sym, false), ident_span);
let next_token = (Token::new(token::Dot, dot_span), self.token_spacing);
self.parse_expr_tuple_field_access(lo, base, sym, None, Some(next_token))
}
// 1.2 | 1.2e3
DestructuredFloat::MiddleDot(symbol1, ident1_span, dot_span, symbol2, ident2_span) => {
self.token = Token::new(token::Ident(symbol1, false), ident1_span);
// This needs to be `Spacing::Alone` to prevent regressions.
// See issue #76399 and PR #76285 for more details
let next_token1 = (Token::new(token::Dot, dot_span), Spacing::Alone);
let base1 =
self.parse_expr_tuple_field_access(lo, base, symbol1, None, Some(next_token1));
let next_token2 = Token::new(token::Ident(symbol2, false), ident2_span);
self.bump_with((next_token2, self.token_spacing)); // `.`
self.parse_expr_tuple_field_access(lo, base1, symbol2, suffix, None)
}
DestructuredFloat::Error => base,
}
}
fn parse_expr_tuple_field_access(
&mut self,
lo: Span,