Repository Guidelines

Project Structure & Module Organization

src/ holds the compiler implementation (lex.c, parse.c, codegen.c, etc.).
demo/ contains small C programs that exercise supported features and serve as manual regressions.
test/ lives beside a custom Makefile that builds build/test_runner; tests compile src/*.c alongside dedicated helper files.
selfhost/ stores headers for the bootstrap compiler, temporary build artifacts, and the demo-check harness.
Generated outputs (build/, selfhost/bootstrap/, selfhost/build/, selfhost/demo_check/) are ignored by .gitignore and should not be committed.

make – stage-1 build using system clang; produces build/llvm7.
make selfhost – uses build/llvm7 to preprocess src/*.c, emit IR, and build build/llvm7_selfhost.
make selfhost_verify – quick comparison of IR output between Stage 1 and Stage 2 for a single file.
make selfhost_test – preprocesses demo/*.c, compiles via the self-hosted compiler, links, and verifies exit codes for known demos.
make bootstrap_compare – runs the full bootstrap pipeline (tc1 vs tc2 IR) for all source files and diffs outputs.
make bootstrap_check – comprehensive integrity check; runs unit tests followed by bootstrap_compare.
make test – runs test/Makefile, building the test_runner that executes all lexer/parse/codegen unit tests.

Follow conventional C style: 4-space indentation, braces on the same line, descriptive variable names (node, ctx, builder).
Use uppercase for #include identifiers (#include "parse.h"), keep functions in snake_case, types in CamelCase when referring to structs (Type, Node).
Keep compiler helpers modular (lex, parse, codegen) and avoid mixing UI/output logic with parsing.
No automated formatter; rely on manual alignment and clarity. Watch for consistent ctx-> usage when threading state.

Tests live under test/ and use the micro-unit helper suite (mu_assert). Each test returns NULL on success.
Name new tests test_<scope>_<behavior> for clarity (e.g., test_generate_switch_case_after_return_case).
Run make test whenever modifying parsing/codegen; target line coverage is functional rather than numeric.
Add regression data to test/common helpers when new fixtures or execution contexts are required.

Commit messages should be concise, prefixed if needed (“fix:”/“feat:” etc.), and mention the key change (e.g., fix: sync tc2 string linkage).
Pull requests should describe the bootstrap impact, any new demo/test targets touched, and reference relevant issues or bootstrap logs.
Include command outputs when reporting regressions (e.g., make bootstrap_compare diffs, make test results).

Manual preprocessing is required for #include/#define: expand with clang -E before passing to build/llvm7. Documented in README.md.
Keep selfhost/include/*.h aligned with LLVM C APIs and host headers; missing prototypes can crash tc2 generation.