Function extract_graphql_document 

pub fn extract_graphql_document(
    source_path: &str,
    input: &str,
) -> Result<GraphqlDocument, GraphqlExtractionError>

Parses a standalone SDL or executable GraphQL document.

The function accepts one GraphQL grammar per artifact. A file mixing SDL and executable definitions is rejected because graphql-parser exposes those grammars separately.

Errors

Returns GraphqlExtractionError::InvalidGraphql when neither dedicated parser accepts the complete input.