pub fn index_of(
name: &str,
library: Option<Library>,
) -> Option<(usize, Library)>Expand description
Where the extractor of a feature named so sits in its library, and
which library, looking through jSymbolic first unless one is given:
music21’s getIndex, as (61, JSymbolic) for Range. Nothing for a
name no extractor has.
music21’s own native list ends with its language feature, which is not here, so its index is never answered.