I am developing a simple translator from MathML to Latex, using Lex and Yacc. In my lex file containing the regex rules I have one defined for arithmetic operators [-+*=/]. I want to extended so that it would recognize plus-minus (+-) and invisible times ('&InvisibleTimes'), but I'm unfamiliar with regex and I need some help.
A:
Try this:
([-+*=/]|\+-|&InvisibleTimes)
Note that you need to escape the +
in +-
because it's an operator outside of character classes. You can do this with backslash (as I've done here) or with double quotes. (The double-quote syntax is pretty unusual -- most other regex implementations only use backslash for escaping, so I'd be inclined to use backslashes as it makes the regex more "conventional".)
Laurence Gonsalves
2009-05-25 00:19:52
A:
Zifre
2009-05-25 01:00:31