It's been mentioned in the past many times before, and Tom and Lummox have shown some form of interest in getting proper Regex support in DM beyond Lummox's library.
I wanted to re-open this issue because I've used PCRE quite a bit and find its license suitable for usage in an application like BYOND. The BSD license permits redistribution in binary or source code form either modified or unmodified as long as the copyright notice remains intact and the license remains intact. That doesn't seem like too much of a stretch.
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