Simplify compiler internals; fix event leakage in typed parsers

[STRd6]

Summary

Two commits.

1. Pure refactor, byte-identical output

• Merge the three terminal-interning functions (defineTerminal, defineRe, defineDynamicRe) into one intern helper.
• Drop the types parameter threaded through compileOp; it was never read.
• Write tsHead as a literal instead of deriving it from mjsHead via regex replace and a match on the import block.
• Share the indented rule-name list between the grammar object and the ESM export block.
• Collapse prettyPrint to one expression.

2. Unify the JS and TS parser tails, fixing a bug

• The typed tail hoisted Validator() and ctx out of parse into an IIFE, so Object.assign(ctx, options.events) from one call persisted into later calls. The untyped tail created them per call. Confirmed: after parse("a", { events: { enter } }) then parse("a"), the typed parser fired enter twice, the untyped one once.
• Both outputs now use one per-call template with type annotations slotted in when types is set.
• Regression test covers both JS and typed (via transpileTsToJs) parsers.

Verification

Snapshotted compiler output for source/hera.hera, every sample, and the inference fixture across ten option combinations (js/ts, cjs/esm, civet, tokenize, custom libPath, inline map), 180 files total.

• After commit 1: all 180 identical.

• After commit 2: untyped outputs identical. Typed outputs differ only in the parser tail, as intended.

• c8 mocha — 210 passing, 100% coverage

• pnpm test:typed-parser-samples

• pnpm test:esbuild-plugin

• pnpm test:loaders

🤖 Generated with Claude Code

https://claude.ai/code/session_01P6RAoyCaAv1Xe7FjMYwD3b

[greptile-apps]

Greptile Summary

This PR simplifies compiler source generation while fixing typed parsers so runtime event hooks cannot persist across parse() calls.

• Consolidates literal, regular-expression, and dynamic-regular-expression interning.
• Removes an unused argument from recursive operator compilation.
• Shares rule-list and parser-tail generation across output modes.
• Creates validator and event context state independently for every parse invocation.
• Adds a regression test covering typed and untyped generated parsers.

Confidence Score: 5/5

The PR appears safe to merge with no actionable correctness, security, or repository-rule issues identified.

The refactors preserve prior generation semantics, while the parser-tail change correctly scopes validator and event state to individual calls and is covered by a focused typed and untyped regression test.

Important Files Changed

Filename	Overview
source/compiler.civet	Consolidates compiler helpers and generated parser tails while moving validator and event context creation into each parse invocation.
test/main.civet	Adds a runtime regression test proving event callbacks do not carry into subsequent typed or untyped parser calls.
CHANGELOG.md	Documents the corrected event isolation behavior for typed generated parsers.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  A[Hera grammar] --> B[Compiler]
  B --> C[Generated JS or TS parser]
  C --> D[parse call]
  D --> E[Fresh Validator]
  D --> F[Fresh event context]
  E --> G[Rule execution and validation]
  F --> G
  G --> H[Parse result]

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_{Reviews (1): Last reviewed commit: "Unify parser tails; fix event leakage in..." | Re-trigger Greptile}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (ba1d299) to head (15d0e73).

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #103   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            9         9           
  Lines         1903      1886   -17     
  Branches       311       307    -4     
=========================================
- Hits          1903      1886   -17     

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[edemaine]

Perhaps add an optional "newline before close brace" argument so you can use it in export below?

[STRd6]

Done in b1bd9cf: ruleNameBlock(names, closeOnOwnLine) now emits the braces, and both the grammar object and export use it. Output verified unchanged against the snapshot.

[edemaine]

I'd probably inline compileRulesObject now i.e. just use ruleNameBlock

[STRd6]

Inlined; compileRulesObject is gone and the call site uses ruleNameBlock directly. Branch squashed to one commit and rebased on main.