Developers

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Prerequisites

• A recent stable Rust toolchain. See rust-lang.org/tools/install.
• For tree-sitter grammar regeneration (Go / C / PowerShell): a Linux or macOS shell, or Windows via WSL.
• ANTLR grammar regeneration (Kotlin, Java, C#) needs no separately installed generator: xtask links the workspace-pinned antlr-rust-codegen crate directly. Keep that exact pin in lockstep with antlr-rust-runtime; a normal build still uses the checked-in modules.
• For the C# grammar specifically, also uv: the Roslyn grammar is transformed by crates/mehen-csharp-parser/grammar/prepare-grammar.py, run as a step of generation via its PEP 723 inline metadata.

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Clone

# HTTPS
git clone -j8 https://github.com/ophi-dev/mehen.git

# SSH
git clone -j8 git@github.com:ophi-dev/mehen.git

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Build and lint

cargo check
cargo build
cargo fmt --all
cargo clippy --all-targets --all-features --locked

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Testing

if cargo nextest --version >/dev/null 2>&1; then
  cargo nextest run --all-features
else
  cargo test --all-targets --locked
fi

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Snapshot tests (insta)

cargo insta test --workspace --all-features --check --unreferenced reject \
    --test-runner nextest --no-test-runner-fallback --disable-nextest-doctest

cargo insta test --workspace --all-features --review \
    --test-runner nextest --no-test-runner-fallback --disable-nextest-doctest

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Repository layout

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Coding expectations

• Keep internals internal (pub(crate) / private) unless a real external API is needed.
• Prefer explicit imports over wildcard re-exports.
• Avoid dead code — this is a CLI-focused codebase.
• Preserve deterministic metric behavior across platforms.

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Pages

• How-to: Add a new language
• How-to: Implement LoC
• How-to: Update grammars

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Contributing