[csharp/v8-spec] Continued improvements in the C# grammar.#4832
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kaby76 wants to merge 17 commits into
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[csharp/v8-spec] Continued improvements in the C# grammar.#4832kaby76 wants to merge 17 commits into
kaby76 wants to merge 17 commits into
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…toring. Three rules — null_coalescing_expression, expression, and range_expression — had alternatives sharing a long common prefix (unary_expression or conditional_or_expression), forcing ANTLR4's SLL simulation to scan up to 30 tokens before resolving the decision. Left-factor each rule so the shared prefix is consumed unconditionally and only a single token of lookahead is needed for the optional suffix. Add design docs explaining the problem and fix for each rule. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
… (decision 31)
Extend IsConstantPatternAhead() to return false when LT(1) is '(' and a
comma appears at parenthesis depth 1 — indicating a tuple-positional pattern
such as ("rock", "scissors") or (0, 0), which cannot be a compile-time
constant. Add IsPositionalPatternAhead() as its complement and gate the
positional_pattern alternative in the grammar with it, making alts 2 and 4
mutually exclusive. Add design/pattern_positional.md documenting the
ambiguity and the fix.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
… to all targets Apply the same tuple-comma check and IsPositionalPatternAhead complement to all remaining language targets: Antlr4ng, Cpp (header + impl), Dart, Go, Java, JavaScript, Python3, and TypeScript. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
…ional_expression, doc cleanup
- All targets: fix IsConstantPatternAhead() to detect type-headed positional
patterns like Point(0,0) where LT(1) is an identifier, not '('.
C#/Java/Python3/Cpp use speculative type_() parse; Antlr4ng/TS/JS/Go/Dart
use LT(1)==identifier && LT(2)=='(' heuristic.
- CSharpParser.g4: rewrite conditional_expression to use explicit '?'
optional instead of the empty-alt form.
- design/primary_expression_mlr.md: fix stray backslashes in code blocks
(change '\' to '//' to match commenting style).
- design/pattern_positional.md: correct last table row — alt 2 is false
(speculative type_() + '(' suppresses it), alt 4 is true.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
… before left-factoring Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
…ax-k 16→14 Left-factor field/method/property/indexer declarations in class_member_declaration, struct_member_declaration, and interface_member_declaration into a shared typed_member_declaration rule. Consuming the common attributes/modifiers/type_ prefix once forces immediate SLL→LL fallback for the ambiguous identifier-led alternatives, dropping max-k from 16 to 14 and parse time ~3×. Also add IsPrimaryConstraintAhead() / IsSecondaryConstraintAhead() predicates and fix BeginVariableDeclaration() to fall back to the parent context (typed_member_declaration) when the current context has no children yet. Both fixes applied to all nine target ports: CSharp, Java, Python3, Go, TypeScript, Antlr4ng, JavaScript, Cpp, Dart. Add design/typed_member_declaration.md documenting the root cause, failed sub-rule grouping approach, and the left-factoring solution. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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The ECMA 334 Committee is currently working on the spec. Waiting for it to stabilize. |
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