AS3 RegExp to match words with boundry type characters in them

Question

I'm wanting to match a list of words which is easy enough when those words are truly words. For example /\b (pop|push) \b/gsx when ran against the string

pop gave the door a push but it popped back

will match the words pop and push but not popped.

I need similar functionality for words that contain characters that would normally qualify as word boundaries. So I need /\b (reverse!|push) \b/gsx when ran against the string

push reverse! reverse!push

to only match reverse! and push but not match reverse!push. Obviously this regex isn't going to do that so what do I need to use instead of \b to make my regex smart enough to handle these funky requirements?

Answer 1

At the end of a word, \b means "the previous character was a word character, and the next character (if there is a next character) is not a word character. You want to drop the first condition because there might be a non-word character at the end of the "word". That leaves you with a negative lookahead:

/\b (reverse!|push) (?!\w)/gx

I'm pretty sure AS3 regexes support lookahead.