Talk:Text between

I think the specification for this problem needs some more information, specifically:

How should implementations behave if the end delimiter is found in the search string before the start delimiter?

Must an error be raised when a delimiter is not present in the search string? Some implementations do this, and some do not.

Are null/missing (or equivalent) delimiters allowed?

Are empty-string delimiters allowed? If so, how should they work? Are empty-string start delimiters equivalent to "start" special delims, and empty-string end delimiters equivalent to "end"?