parse_feature_expression

Note

This page is a reference documentation. It only explains the function signature, and not how to use it. Please refer to the Habitat Guide and Python API guide (v2.0) for usage.

parse_feature_expression(expression: str) → Spec[source]

Parse one feature-tree expression into its canonical Spec tree.

This is the strict v1 spelling: quoted modality names, explicit key=value parameters, nested calls for combiner children. The v0 bare-token mini-language is handled by the legacy config adapter instead; this parser deliberately rejects it so ambiguous expressions fail loudly rather than silently guessing.

Parameters:: expression – The expression, e.g. 'concat(raw("T1"), ratio(raw("T1"), raw("T2"), as_="r"))'.
Returns:: The root node’s Spec; combiner children nest under params['children'] as Spec.to_dict() payloads.
Raises:: HABITAPIError – On any malformed or ambiguous input.