transcribe: Move substitute_metavar in its own function

1 files changed, 34 insertions, 0 deletions

diff --git a/gcc/rust/expand/rust-macro-expand.h b/gcc/rust/expand/rust-macro-expand.h
index edb091d..f77acc7 100644
--- a/gcc/rust/expand/rust-macro-expand.h
+++ b/gcc/rust/expand/rust-macro-expand.h
@@ -183,6 +183,40 @@ struct MacroExpander
 			size_t &match_amount, size_t lo_bound = 0,
 			size_t hi_bound = 0);
 
+  /**
+   * Substitute a metavariable by its given fragment in a transcribing context,
+   * i.e. replacing $var with the associated fragment.
+   *
+   * @param input Tokens given to the transcribing context
+   * @param fragments Fragments given to the macro substitution
+   * @param metavar Metavariable to try and replace
+   *
+   * @return A token containing the associated fragment expanded into tokens if
+   * any, or the cloned token if no fragment was associated
+   */
+  static std::vector<std::unique_ptr<AST::Token>>
+  substitute_metavar (std::vector<std::unique_ptr<AST::Token>> &input,
+		      std::map<std::string, MatchedFragment> &fragments,
+		      std::unique_ptr<AST::Token> &metavar);
+
+  /**
+   * Substitute a given token by its appropriate representation
+   *
+   * @param input Tokens given to the transcribing context
+   * @param fragments Fragments given to the macro substitution
+   * @param token Current token to try and substitute
+   *
+   * @return A token containing the associated fragment expanded into tokens if
+   * any, or the cloned token if no fragment was associated, as well as the
+   * amount of tokens that should be skipped before the next invocation. Since
+   * this function may consume more than just one token, it is important to skip
+   * ahead of the input to avoid mis-substitutions
+   */
+  static std::pair<std::vector<std::unique_ptr<AST::Token>>, size_t>
+  substitute_token (std::vector<std::unique_ptr<AST::Token>> &input,
+		    std::map<std::string, MatchedFragment> &fragments,
+		    std::unique_ptr<AST::Token> &token);
+
   static std::vector<std::unique_ptr<AST::Token>>
   substitute_tokens (std::vector<std::unique_ptr<AST::Token>> &input,
 		     std::vector<std::unique_ptr<AST::Token>> &macro,