- (textual-filter pred textual [start end]) → textprocedure
- (textual-remove pred textual [start end]) → textprocedure
Filter the given subtext of textual, retaining only those characters that satisfy / do not satisfy pred.
If textual is a string, then that string does not share any storage with the result, so subsequent mutation of that string will not affect the text returned by these procedures. If textual is a text, the result shares storage with that text whenever sharing would be space-efficient.