Member predicate RegExp::char_set_delimiter
Helper predicate for chars that could be character-set delimiters.
Holds if the (non-escaped) char at pos
in the string, is the (one-based) index
occurrence of a bracket ([
or ]
) in the string.
Result if true
is the char is [
, and false
if the char is ]
.
boolean char_set_delimiter(int index, int pos)