Module template 

String substitution for path templates and message templates.

Two variants, distinguished by delimiter style:

• Path templates — single braces, fixed token set derived from a matched file’s relative path. Example: "{dir}/{stem}.h".
• Message templates — double braces, namespaced lookups for rule messages and similar user-facing strings. Example: "{{ctx.primary}} has no matching header at {{ctx.partner}}".

Both are intentionally small and self-contained: no regex dependency, no dynamic parser. Unknown tokens are preserved literally so a typo surfaces in output rather than silently blanking out.

Structs

PathTokens

Token values derived from a relative path. Consumed by render_path and by cross-file rules to resolve partner paths.

Functions

render_mapping

Substitute {{namespace.key}} placeholders in a message template. The caller-supplied resolve closure returns the substituted value, or None to leave the placeholder literal.

render_message

render_path

Substitute {token} placeholders in a path-shaped template. Unknown tokens are preserved literally (so "{unknown}" renders as "{unknown}").

render_paths_spec

Apply path-template substitution to every pattern in a PathsSpec.

render_value

Recursive mate to render_mapping for arbitrary YAML values.