parser-tree

You can use reussir-syntax (built with cmake --build build --target reussir-syntax; binary at build/bin/reussir-syntax) to parse Reussir source code. It emits the surface AST as JSON, and can also just validate that a file parses.

To check that a file parses (report diagnostics, no output on success):

build/bin/reussir-syntax --check tests/integration/frontend/fibonacci.rr

On a syntax error it renders each diagnostic with source context on stderr and exits non-zero; the parser recovers and reports every error, not just the first.

To emit the JSON surface AST (to stdout, or -o PATH):

build/bin/reussir-syntax tests/integration/frontend/fibonacci.rr -o -

The output is a single JSON document encoding the spanned AST, e.g.:

[{"contents":{"spanStartOffset":...,"spanValue":{"contents":{"recordDefaultCap":"Value",
"recordFields":{...}}}}}, ...]

For a human-readable view of the elaborated program instead of the raw parse tree, prefer rrc --emit hir (see the elaboration skill). The detailed structural assertions the parser needs are covered by reussir-syntax's own Rust unit tests (cmake --build build --target rrc-test runs the crate suites).