Make a Matcher that returns either a match from a given parser or a match with the default value (without consuming input in that case).
Use eitherOr if you want to provide a Matcher instead of a constant default value.
A parser.
Default value to be returned in case parser didn't match.
Make a Matcher that returns either a match from a given parser or a match with the default value (without consuming input in that case).
Use eitherOr if you want to provide a Matcher instead of a constant default value.