kc3-lang/libxkbcommon/src/xkbcomp/include.h

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• Hash : 23598fa1
  Author :
  Date : 2025-03-25T22:52:06
  

  Enable merge mode “replace” in include statements
  
  Previously only the merge modes “override” and “augment” were available
  in include statements, using the prefix ‘+’ and ‘|’ respectively. While
  on one hand `replace` include statement can be used in keymap files, on
  the other hand *rules* files have no way to express the *replace* mode.
  
  This commit enables the merge mode “replace” using the prefix `^`. This
  prefix was chosen due to its similarity with the `XOR` bit operator,
  which convey *mutual exclusion*.
  
  Other candidates:
  - `!` conveys some kind of higher precedence, akin to CSS `!important`.
    But it conflicts with the section header `!`, which is a token in the
    current parser. It would require special handling, not worth it. It
    also convey the meaning of negation, which is confusing.
  - `&` has the advantage of not corresponding to a token in the rules
    parser. `^` seems however to stand out more and it is less likely to
    trigger erroneous comparison with `|` and `&` bit operators.
  

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• src/xkbcomp/include.h

• /*
   * Copyright (c) 1994 by Silicon Graphics Computer Systems, Inc.
   * SPDX-License-Identifier: HPND
   */
  #pragma once
  
  #include "ast.h"
  
  /* Reasonable threshold, with plenty of margin for keymaps in the wild */
  #define INCLUDE_MAX_DEPTH 15
  
  #define MERGE_OVERRIDE_PREFIX '+'
  #define MERGE_AUGMENT_PREFIX  '|'
  #define MERGE_REPLACE_PREFIX  '^'
  #define MERGE_DEFAULT_PREFIX  MERGE_OVERRIDE_PREFIX
  #define is_merge_mode_prefix(ch) \
      ((ch) == MERGE_OVERRIDE_PREFIX || (ch) == MERGE_AUGMENT_PREFIX || \
       (ch) == MERGE_REPLACE_PREFIX)
  static const char MERGE_MODE_PREFIXES[] =
      { MERGE_OVERRIDE_PREFIX, MERGE_AUGMENT_PREFIX, MERGE_REPLACE_PREFIX, 0 };
  
  bool
  ParseIncludeMap(char **str_inout, char **file_rtrn, char **map_rtrn,
                  char *nextop_rtrn, char **extra_data);
  
  FILE *
  FindFileInXkbPath(struct xkb_context *ctx, const char *name,
                    enum xkb_file_type type, char **pathRtrn,
                    unsigned int *offset);
  
  bool
  ExceedsIncludeMaxDepth(struct xkb_context *ctx, unsigned int include_depth);
  
  XkbFile *
  ProcessIncludeFile(struct xkb_context *ctx, IncludeStmt *stmt,
                     enum xkb_file_type file_type);
  

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