Function include_directives 

pub fn include_directives(text: &str) -> Vec<String>

The #!include targets declared in text, in source order — the same directive spellings ("..." or '...') the preprocessor honors. Callers mapping a document set’s include graph (for example a provider ordering entry checks before member fallbacks) can use this without reimplementing the directive syntax. A text that fails to lex contributes no targets.