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       1                 :             : // Copyright (C) 2020-2025 Free Software Foundation, Inc.
       2                 :             : 
       3                 :             : // This file is part of GCC.
       4                 :             : 
       5                 :             : // GCC is free software; you can redistribute it and/or modify it under
       6                 :             : // the terms of the GNU General Public License as published by the Free
       7                 :             : // Software Foundation; either version 3, or (at your option) any later
       8                 :             : // version.
       9                 :             : 
      10                 :             : // GCC is distributed in the hope that it will be useful, but WITHOUT ANY
      11                 :             : // WARRANTY; without even the implied warranty of MERCHANTABILITY or
      12                 :             : // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      13                 :             : // for more details.
      14                 :             : 
      15                 :             : // You should have received a copy of the GNU General Public License
      16                 :             : // along with GCC; see the file COPYING3.  If not see
      17                 :             : // <http://www.gnu.org/licenses/>.
      18                 :             : 
      19                 :             : #include "rust-ast.h"
      20                 :             : #include "rust-macro-expand.h"
      21                 :             : 
      22                 :             : namespace Rust {
      23                 :             : class SubstituteCtx
      24                 :             : {
      25                 :             :   std::vector<std::unique_ptr<AST::Token>> &input;
      26                 :             :   std::vector<std::unique_ptr<AST::Token>> &macro;
      27                 :             :   std::map<std::string, MatchedFragmentContainer *> &fragments;
      28                 :             : 
      29                 :             :   /**
      30                 :             :    * Find the repetition amount to use when expanding a repetition, and
      31                 :             :    * check that all fragments used respect that repetition amount
      32                 :             :    *
      33                 :             :    * @param pattern_start Start of the repetition pattern
      34                 :             :    * @param pattern_end End of the repetition pattern
      35                 :             :    * @param repeat_amount Reference to fill with the matched repetition amount
      36                 :             :    */
      37                 :             :   bool check_repetition_amount (size_t pattern_start, size_t pattern_end,
      38                 :             :                                 size_t &repeat_amount);
      39                 :             : 
      40                 :             : public:
      41                 :        5161 :   SubstituteCtx (std::vector<std::unique_ptr<AST::Token>> &input,
      42                 :             :                  std::vector<std::unique_ptr<AST::Token>> &macro,
      43                 :             :                  std::map<std::string, MatchedFragmentContainer *> &fragments)
      44                 :        5161 :     : input (input), macro (macro), fragments (fragments)
      45                 :             :   {}
      46                 :             : 
      47                 :             :   /**
      48                 :             :    * Substitute a metavariable by its given fragment in a transcribing context,
      49                 :             :    * i.e. replacing $var with the associated fragment.
      50                 :             :    *
      51                 :             :    * @param metavar Metavariable to try and replace
      52                 :             :    * @param expanded Reference to a vector upon which expanded tokens will be
      53                 :             :    * pushed
      54                 :             :    *
      55                 :             :    * @return True iff the substitution succeeded
      56                 :             :    */
      57                 :             :   bool substitute_metavar (std::unique_ptr<AST::Token> &metavar,
      58                 :             :                            std::vector<std::unique_ptr<AST::Token>> &expanded);
      59                 :             : 
      60                 :             :   /**
      61                 :             :    * Substitute a macro repetition by its given fragments
      62                 :             :    *
      63                 :             :    * @param pattern_start Start index of the pattern tokens
      64                 :             :    * @param pattern_end End index of the patterns tokens
      65                 :             :    * @param separator Optional separator to include when expanding tokens
      66                 :             :    *
      67                 :             :    * @return A vector containing the repeated pattern
      68                 :             :    */
      69                 :             :   std::vector<std::unique_ptr<AST::Token>>
      70                 :             :   substitute_repetition (size_t pattern_start, size_t pattern_end,
      71                 :             :                          std::unique_ptr<AST::Token> separator);
      72                 :             : 
      73                 :             :   /**
      74                 :             :    * Substitute a given token by its appropriate representation
      75                 :             :    *
      76                 :             :    * @param token_idx Current token to try and substitute
      77                 :             :    *
      78                 :             :    * @return A token containing the associated fragment expanded into tokens if
      79                 :             :    * any, or the cloned token if no fragment was associated, as well as the
      80                 :             :    * amount of tokens that should be skipped before the next invocation. Since
      81                 :             :    * this function may consume more than just one token, it is important to skip
      82                 :             :    * ahead of the input to avoid mis-substitutions
      83                 :             :    */
      84                 :             :   std::pair<std::vector<std::unique_ptr<AST::Token>>, size_t>
      85                 :             :   substitute_token (size_t token_idx);
      86                 :             : 
      87                 :             :   /**
      88                 :             :    * Substitute all tokens by their appropriate representation
      89                 :             :    *
      90                 :             :    * @return A vector containing the substituted tokens
      91                 :             :    */
      92                 :             :   std::vector<std::unique_ptr<AST::Token>> substitute_tokens ();
      93                 :             : };
      94                 :             : } // namespace Rust