match_ID returned by DependencyMatcher._call__ method should be type str not int

[omarzd]

The method DependencyMatcher._call__ returns match_ID as type int even though match_ID is type str everywhere else including when it is set by the user. I think for the sake of consistency and usability, this should be fixed.

[adrianeboyd]

Hi, spacy stores most strings internally as ints for efficiency, so the matchers (Matcher, PhraseMatcher, and DependencyMatcher) also do this for the match IDs. As far as I know they've always returned matches in this format.

I can totally understand why you'd prefer strings instead, but we want to keep these kinds of APIs the same as much as possible and we want to keep it as efficient as possible internally, too.

For Matcher, there's the new as_spans option which is a little more user-friendly, but there's no good alternative format like Span for storing non-contiguous dependency match results.