kc3-lang/libxkbcommon/changes/api/+extended-rules-wild-cards.feature.md

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• Hash : 6fc6e64b
  Author :
  Date : 2025-03-26T10:35:22
  

  rules: Added extended wild cards <none>, <some> and <any>
  
  Added the following wild cards to the rules file syntax, in addition
  to the current `*` legacy wild card:
  - `<none>`: Match *empty* value.
  - `<some>`: Match *non-empty* value.
  - `<any>`: Match *any* (optionally empty) value. Its behavior does not
    depend on the context, contrary to the legacy wild card `*`.
  
  This will enable writing much simpler rules, see [!764] for an example
  of tricky rules in the `xkeyboard-config` project, that would benefit
  from the new wild cards.
  
  [!764]: https://gitlab.freedesktop.org/xkeyboard-config/xkeyboard-config/-/merge_requests/764
  
  The verbose wild cards are preferred to single characters:
  - More intuitive: self-explanatory.
  - Does not steal syntax from other token.
  - Extensible syntax, should we need it.
  
  A previous proposal used the characters (`!`, `+`, `?`) for their
  similarity with the corresponding syntax of regular expressions
  (negative assertion & quantifiers), in line with `*`. But `!` is not
  that intuitive after all and conflict with its role as section header.
  Furthermore, `+` is also used as a merge mode. Finally, nothing beats
  whole short words for readability.
  

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• changes/api/+extended-rules-wild-cards.feature.md

• Added the following *wild cards* to the **rules** file syntax, in addition to
  the current `*` legacy wild card:
  - `<none>`: Match *empty* value.
  - `<some>`: Match *non-empty* value.
  - `<any>`: Match *any* (optionally empty) value. Its behavior does not depend on
    the context, contrary to the legacy wild card `*`.
  

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