Eric Blake wrote: > M4 1.4.x only supports the glibc emacs flavor of regexp. M4 2.0 has > improved regex support, allowing you to choose different flavors > supported by glibc, such as strict posix, extended regex, and so > forth, but still needs tweaking before it will support tunables like > case-insensitivity.
So the non-greedy "?" postfix operator is not available below m4-2, did I get this right? It takes so much time to experimentally determine what works and what doesn't, would it be possible to document the RE syntax available in m4-1.x? Even if only a README text, it would help quite a bit. I even tried to get this info from the source, but it contains a sizeable chunk of regex code in lib/reg*, some of which seems to be there for compatibility/portability, so I eventually gave up. > M4 2.0 will allow modules, so it is conceivable that someone could add > a PCRE module for a different regex engine. But the default will > still be to provide only what glibc provides (even on non-glibc > platforms, since gnulib's regex implementation mirrors glibc). Yes, conceivable, but propably too much hassle for people who want to publish their code in source form, compared to using hack-arounds with vendor-supplied m4. I guess regex modules would be made and used in house, maybe even contributed some day. clemens
