Implement %inline feature compliant with Menhir specification
#771
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This PR makes Lrama's inline feature compliant with the [Menhir](https://gallium.inria.fr/~fpottier/menhir/) specification. Changed from macro-like substitution (simple string replacement of `$n`) to a temporary variable binding approach. Before: ```c // Simple substitution of $2 with inline_action_string $$ = $1 inline_action_string $3; ``` After: ```c // Variable binding ensures single evaluation YYSTYPE _inline_2; { _inline_2 = '+'; } $$ = $1 _inline_2 $3; ``` This resolves the issue where inline actions with side effects could be evaluated multiple times. Added a Validator that detects the following errors per Menhir specification: - Direct recursion (inline rule references itself) - Mutual recursion (multiple inline rules form a reference cycle) - Start symbol declared as inline Added an option to ignore all `%inline` keywords in the grammar specification. Useful for verifying whether inlining contributes to conflict resolution. Added samples demonstrating the core use case of `%inline` (resolving precedence conflicts): - `sample/calc_inline.y`: Resolves precedence issue with `%inline` - `sample/calc_no_inline.y`: Shows conflicts without `%inline` - [Menhir Reference Manual - Inlining](https://gallium.inria.fr/~fpottier/menhir/manual.html#sec%3Ainlining) - [Menhir GitHub Repository](https://github.com/LexiFi/menhir)
yui-knk
reviewed
Jan 22, 2026
lib/lrama/grammar/inline/resolver.rb
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| next if ref.index.nil? || ref.index <= index # nil は $$ の場合 | ||
| code = code.gsub(/\$#{ref.index}/, "$#{ref.index + (rhs.symbols.count - 1)}") | ||
| code = code.gsub(/@#{ref.index}/, "@#{ref.index + (rhs.symbols.count - 1)}") | ||
| next if ref.index.nil? || ref.index <= index + 1 # nil は $$、index + 1 は inline 位置 |
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Could you rewrite this comment with English?
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Does this mean inline rules are treated as a usual (non inline) rules when |
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Yes. When --no-inline is specified, inline rules are treated as regular (non-inline) rules. However, the implementation was insufficient, so I added 30d92ac |
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This PR makes Lrama's inline feature compliant with the Menhir specification.
Key Changes
Menhir-style Variable Binding for Action Merging
Changed from macro-like substitution (simple string replacement of
$n) to a temporary variable binding approach.Before:
After:
This resolves the issue where inline actions with side effects could be evaluated multiple times.
Added Recursion Detection Validator
Added a Validator that detects the following errors per Menhir specification:
Added
--no-inlineOptionAdded an option to ignore all
%inlinekeywords in the grammar specification. Useful for verifying whether inlining contributes to conflict resolution.Added Sample Files
Added samples demonstrating the core use case of
%inline(resolving precedence conflicts):sample/calc_inline.y: Resolves precedence issue with%inlinesample/calc_no_inline.y: Shows conflicts without%inlineReferences