bjoernager/rust
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Remove TreeAndSpacing.

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A `TokenStream` contains a `Lrc<Vec<(TokenTree, Spacing)>>`. But this is
not quite right. `Spacing` makes sense for `TokenTree::Token`, but does
not make sense for `TokenTree::Delimited`, because a
`TokenTree::Delimited` cannot be joined with another `TokenTree`.

This commit fixes this problem, by adding `Spacing` to `TokenTree::Token`,
changing `TokenStream` to contain a `Lrc<Vec<TokenTree>>`, and removing the
`TreeAndSpacing` typedef.

The commit removes these two impls:
- `impl From<TokenTree> for TokenStream`
- `impl From<TokenTree> for TreeAndSpacing`

These were useful, but also resulted in code with many `.into()` calls
that was hard to read, particularly for anyone not highly familiar with
the relevant types. This commit makes some other changes to compensate:
- `TokenTree::token()` becomes `TokenTree::token_{alone,joint}()`.
- `TokenStream::token_{alone,joint}()` are added.
- `TokenStream::delimited` is added.

This results in things like this:
```rust
TokenTree::token(token::Semi, stmt.span).into()
```
changing to this:
```rust
TokenStream::token_alone(token::Semi, stmt.span)
```
This makes the type of the result, and its spacing, clearer.

These changes also simplifies `Cursor` and `CursorRef`, because they no longer
need to distinguish between `next` and `next_with_spacing`.
This commit is contained in:
Nicholas Nethercote 2022-07-28 10:31:04 +10:00
parent bdf520fd41
commit 332dffb1f9
23 changed files with 317 additions and 307 deletions
Download patch file Download diff file Expand all files Collapse all files

36
compiler/rustc_expand/src/parse/tests.rs
View file

@ -66,23 +66,23 @@ fn string_to_tts_macro() {
match tts {
[
TokenTree::Token(Token { kind: token::Ident(name_macro_rules, false), .. }),
TokenTree::Token(Token { kind: token::Not, .. }),
TokenTree::Token(Token { kind: token::Ident(name_zip, false), .. }),
TokenTree::Token(Token { kind: token::Ident(name_macro_rules, false), .. }, _),
TokenTree::Token(Token { kind: token::Not, .. }, _),
TokenTree::Token(Token { kind: token::Ident(name_zip, false), .. }, _),
TokenTree::Delimited(_, macro_delim, macro_tts),
] if name_macro_rules == &kw::MacroRules && name_zip.as_str() == "zip" => {
let tts = &macro_tts.trees().collect::<Vec<_>>();
match &tts[..] {
[
TokenTree::Delimited(_, first_delim, first_tts),
TokenTree::Token(Token { kind: token::FatArrow, .. }),
TokenTree::Token(Token { kind: token::FatArrow, .. }, _),
TokenTree::Delimited(_, second_delim, second_tts),
] if macro_delim == &Delimiter::Parenthesis => {
let tts = &first_tts.trees().collect::<Vec<_>>();
match &tts[..] {
[
TokenTree::Token(Token { kind: token::Dollar, .. }),
TokenTree::Token(Token { kind: token::Ident(name, false), .. }),
TokenTree::Token(Token { kind: token::Dollar, .. }, _),
TokenTree::Token(Token { kind: token::Ident(name, false), .. }, _),
] if first_delim == &Delimiter::Parenthesis && name.as_str() == "a" => {
}
_ => panic!("value 3: {:?} {:?}", first_delim, first_tts),
@ -90,8 +90,8 @@ fn string_to_tts_macro() {
let tts = &second_tts.trees().collect::<Vec<_>>();
match &tts[..] {
[
TokenTree::Token(Token { kind: token::Dollar, .. }),
TokenTree::Token(Token { kind: token::Ident(name, false), .. }),
TokenTree::Token(Token { kind: token::Dollar, .. }, _),
TokenTree::Token(Token { kind: token::Ident(name, false), .. }, _),
] if second_delim == &Delimiter::Parenthesis
&& name.as_str() == "a" => {}
_ => panic!("value 4: {:?} {:?}", second_delim, second_tts),
@ -111,29 +111,27 @@ fn string_to_tts_1() {
let tts = string_to_stream("fn a (b : i32) { b; }".to_string());
let expected = TokenStream::new(vec![
TokenTree::token(token::Ident(kw::Fn, false), sp(0, 2)).into(),
TokenTree::token(token::Ident(Symbol::intern("a"), false), sp(3, 4)).into(),
TokenTree::token_alone(token::Ident(kw::Fn, false), sp(0, 2)),
TokenTree::token_alone(token::Ident(Symbol::intern("a"), false), sp(3, 4)),
TokenTree::Delimited(
DelimSpan::from_pair(sp(5, 6), sp(13, 14)),
Delimiter::Parenthesis,
TokenStream::new(vec![
TokenTree::token(token::Ident(Symbol::intern("b"), false), sp(6, 7)).into(),
TokenTree::token(token::Colon, sp(8, 9)).into(),
TokenTree::token(token::Ident(sym::i32, false), sp(10, 13)).into(),
TokenTree::token_alone(token::Ident(Symbol::intern("b"), false), sp(6, 7)),
TokenTree::token_alone(token::Colon, sp(8, 9)),
TokenTree::token_alone(token::Ident(sym::i32, false), sp(10, 13)),
])
.into(),
)
.into(),
),
TokenTree::Delimited(
DelimSpan::from_pair(sp(15, 16), sp(20, 21)),
Delimiter::Brace,
TokenStream::new(vec![
TokenTree::token(token::Ident(Symbol::intern("b"), false), sp(17, 18)).into(),
TokenTree::token(token::Semi, sp(18, 19)).into(),
TokenTree::token_joint(token::Ident(Symbol::intern("b"), false), sp(17, 18)),
TokenTree::token_alone(token::Semi, sp(18, 19)),
])
.into(),
)
.into(),
),
]);
assert_eq!(tts, expected);