regex seems to be a way of life around here .. slow or not in msl (Y)

mIRC uses the PCRE library when matching a regular expression against a string, so most of the time it only needs to perform basic operations whenever regex is involved. the only function where it may be considered suitable to discuss the efficiency of mIRC's implementation, since it performs a significant amount of additional work, is $regsubex() and yes, it is a lot slower than it needs to be. mIRC goes through a rather convoluted process when replacements are made with $regsubex() so you can say that, where it counts, mIRC's implementation of regex is slow.