Development

This page is for contributors modifying the pegtool generator itself. Projects that only use generated parsers do not need these steps.

Repository structure

Path	Contents
grammar/	pegtool's own PEG grammar
ast/	Grammar AST and traversal
builder/	Shared builder and Go runtime
builder_hx/	Haxe target
builder_ts/	TypeScript target
builder_cs/	C# target
builder_c/	C99 target
builder_rust/	Rust target
examples/	Compilable examples for each language
test/	Parser behavior regression tests

Toolchains

Current CI uses Go 1.25. Complete validation of the other targets also requires the relevant toolchains, such as Haxe/HashLink, Node/TypeScript, .NET, a C compiler, and Cargo.

go build .
go test ./...

After modifying static Go or Haxe runtime source, regenerate the template mirrors:

go generate ./builder ./builder_hx

Do not modify only generated_static_code.go; source files and generated mirrors must stay synchronized.

Validate targets

Run at least the tests for affected packages:

go test ./builder ./builder_ts ./builder_hx ./builder_cs ./builder_c ./builder_rust

When shared AST, grammar, or CLI code changes, run:

go test ./...

Generator tests prove only output structure. A user-visible target change should also compile and run a generated parser with tsc --strict, Haxe, dotnet build, a C99 compiler, or cargo test.

Benchmark principles

• Correctness comes before throughput.
• Interleave comparisons on the same machine and toolchain.
• Separate warm-up from measurement for JIT runtimes and repeat with reversed execution order.
• Record generated source size, execution time, allocation counts, and memory.
• Publish only reviewed, stable conclusions in user documentation, not intermediate experiments.

Documentation site

Install dependencies and build the site:

npm install
npm run docs:build

package.json applies a secure version override for Vite. After updating VitePress, rerun npm audit to confirm that the override remains necessary and compatible.

For local editing, use the VitePress documentation script:

npm run docs:dev

Treat docs:build as the release check. It writes output to docs/.vitepress/dist/, which is not committed to Git.

Pull requests that change the documentation run the same production build in GitHub Actions. A documentation change pushed to main is built and deployed to GitHub Pages automatically by the Deploy documentation workflow.

Before committing

1. Format Go code and run goimports.
2. Regenerate affected generated files.
3. Run the relevant target tests and go test ./....
4. Build the VitePress documentation.
5. Check generated output for large diffs unrelated to the syntax change.