Function check_grammar_lowering 

pub fn check_grammar_lowering(
    grammar: &Grammar,
    format: &str,
    options: &GrammarLoweringOptions<'_>,
) -> Result<GrammarLoweringReport, GrammarLoweringError>

Lowers grammar into format, reconstructs it from the package and reports every way the lowering failed.

The failures are an emission note, an executable that does not read back as the lowered grammar, a feature the reconstruction lost, and for an exact lowering an accept or reject sample on which the executable disagrees.

Errors

Returns a GrammarLoweringError when the lowering itself cannot be carried out or a rule definition cannot be normalized.