macros: Allow parsing :tt fragments
:tt fragments stand for token trees, and are composed of either a token, or a delimited token tree, which is a token tree surrounded by delimiters (parentheses, curly brackets or square brackets). This should allow us to handle a lot more macros, including extremely powerful macro patterns such as TT munchers
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@ -497,10 +497,8 @@ MacroExpander::match_fragment (Parser<MacroInvocLexer> &parser,
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gcc_unreachable ();
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break;
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// what is TT?
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case AST::MacroFragSpec::TT:
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// parser.parse_token_tree() ?
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gcc_unreachable ();
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parser.parse_token_tree ();
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break;
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// i guess we just ignore invalid and just error out
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@ -142,6 +142,7 @@ public:
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std::vector<std::unique_ptr<AST::LifetimeParam> > parse_lifetime_params ();
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AST::Visibility parse_visibility ();
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std::unique_ptr<AST::IdentifierPattern> parse_identifier_pattern ();
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std::unique_ptr<AST::TokenTree> parse_token_tree ();
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private:
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void skip_after_semicolon ();
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@ -188,7 +189,6 @@ private:
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// Token tree or macro related
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AST::DelimTokenTree parse_delim_token_tree ();
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std::unique_ptr<AST::TokenTree> parse_token_tree ();
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std::unique_ptr<AST::MacroRulesDefinition>
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parse_macro_rules_def (AST::AttrVec outer_attrs);
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std::unique_ptr<AST::MacroInvocation>
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@ -0,0 +1,13 @@
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macro_rules! t {
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($t:tt) => {
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$t
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};
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}
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fn frob() -> i32 {
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t!(15) + t!((14))
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}
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fn main() -> i32 {
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frob() - 29
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}
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@ -0,0 +1,12 @@
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macro_rules! count_tt {
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($t:tt) => { 1 };
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($t:tt $($ts:tt)*) => { 1 + count_tt!($($ts)*) };
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}
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fn main() -> i32 {
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let count = count_tt!(1 2 let a = 15) + count_tt!(1 2 (let a = 15));
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// ^ ^ ^^^ ^ ^ ^^ ^ ^ ^^^^^^^^^^^^
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// 6 token-trees 3 token-trees
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count - 9
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}
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