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925f7fad57
`tokenstream::Spacing` appears on all `TokenTree::Token` instances, both punct and non-punct. Its current usage: - `Joint` means "can join with the next token *and* that token is a punct". - `Alone` means "cannot join with the next token *or* can join with the next token but that token is not a punct". The fact that `Alone` is used for two different cases is awkward. This commit augments `tokenstream::Spacing` with a new variant `JointHidden`, resulting in: - `Joint` means "can join with the next token *and* that token is a punct". - `JointHidden` means "can join with the next token *and* that token is a not a punct". - `Alone` means "cannot join with the next token". This *drastically* improves the output of `print_tts`. For example, this: ``` stringify!(let a: Vec<u32> = vec![];) ``` currently produces this string: ``` let a : Vec < u32 > = vec! [] ; ``` With this PR, it now produces this string: ``` let a: Vec<u32> = vec![] ; ``` (The space after the `]` is because `TokenTree::Delimited` currently doesn't have spacing information. The subsequent commit fixes this.) The new `print_tts` doesn't replicate original code perfectly. E.g. multiple space characters will be condensed into a single space character. But it's much improved. `print_tts` still produces the old, uglier output for code produced by proc macros. Because we have to translate the generated code from `proc_macro::Spacing` to the more expressive `token::Spacing`, which results in too much `proc_macro::Along` usage and no `proc_macro::JointHidden` usage. So `space_between` still exists and is used by `print_tts` in conjunction with the `Spacing` field. This change will also help with the removal of `Token::Interpolated`. Currently interpolated tokens are pretty-printed nicely via AST pretty printing. `Token::Interpolated` removal will mean they get printed with `print_tts`. Without this change, that would result in much uglier output for code produced by decl macro expansions. With this change, AST pretty printing and `print_tts` produce similar results. The commit also tweaks the comments on `proc_macro::Spacing`. In particular, it refers to "compound tokens" rather than "multi-char operators" because lifetimes aren't operators.
110 lines
4.4 KiB
Plaintext
110 lines
4.4 KiB
Plaintext
PRINT-DERIVE INPUT (DISPLAY): struct Foo
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{
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field :
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[bool ; { #[rustc_dummy] struct Inner { other_inner_field: u8, } 0 }]
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}
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PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): struct Foo
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{
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field :
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[bool ; { #[rustc_dummy] struct Inner { other_inner_field : u8, } 0 }]
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}
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PRINT-DERIVE INPUT (DEBUG): TokenStream [
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Ident {
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ident: "struct",
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span: $DIR/expand-to-derive.rs:16:9: 16:15 (#3),
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},
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Ident {
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ident: "Foo",
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span: $DIR/expand-to-derive.rs:16:16: 16:19 (#3),
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},
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Group {
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delimiter: Brace,
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stream: TokenStream [
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Ident {
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ident: "field",
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span: $DIR/expand-to-derive.rs:18:13: 18:18 (#3),
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},
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Punct {
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ch: ':',
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spacing: Alone,
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span: $DIR/expand-to-derive.rs:18:18: 18:19 (#3),
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},
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Group {
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delimiter: Bracket,
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stream: TokenStream [
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Ident {
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ident: "bool",
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span: $DIR/expand-to-derive.rs:18:21: 18:25 (#3),
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},
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Punct {
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ch: ';',
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spacing: Alone,
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span: $DIR/expand-to-derive.rs:18:25: 18:26 (#3),
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},
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Group {
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delimiter: Brace,
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stream: TokenStream [
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Punct {
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ch: '#',
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spacing: Alone,
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span: $DIR/expand-to-derive.rs:27:5: 27:6 (#0),
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},
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Group {
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delimiter: Bracket,
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stream: TokenStream [
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Ident {
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ident: "rustc_dummy",
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span: $DIR/expand-to-derive.rs:27:28: 27:39 (#0),
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},
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],
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span: $DIR/expand-to-derive.rs:27:5: 27:6 (#0),
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},
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Ident {
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ident: "struct",
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span: $DIR/expand-to-derive.rs:28:5: 28:11 (#0),
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},
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Ident {
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ident: "Inner",
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span: $DIR/expand-to-derive.rs:28:12: 28:17 (#0),
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},
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Group {
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delimiter: Brace,
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stream: TokenStream [
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Ident {
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ident: "other_inner_field",
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span: $DIR/expand-to-derive.rs:30:9: 30:26 (#0),
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},
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Punct {
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ch: ':',
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spacing: Alone,
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span: $DIR/expand-to-derive.rs:30:26: 30:27 (#0),
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},
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Ident {
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ident: "u8",
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span: $DIR/expand-to-derive.rs:30:28: 30:30 (#0),
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},
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Punct {
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ch: ',',
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spacing: Alone,
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span: $DIR/expand-to-derive.rs:30:30: 30:31 (#0),
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},
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],
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span: $DIR/expand-to-derive.rs:28:18: 31:6 (#0),
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},
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Literal {
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kind: Integer,
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symbol: "0",
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suffix: None,
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span: $DIR/expand-to-derive.rs:20:17: 20:18 (#3),
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},
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],
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span: $DIR/expand-to-derive.rs:18:27: 21:14 (#3),
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},
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],
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span: $DIR/expand-to-derive.rs:18:20: 21:15 (#3),
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},
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],
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span: $DIR/expand-to-derive.rs:16:20: 22:10 (#3),
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},
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]
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