CVSROOT: /cvs Module name: src Changes by: schwa...@cvs.openbsd.org 2022/08/06 13:04:49
Modified files: lib/libc/regex : regex.3 Log message: Improve HISTORY and add AUTHORS. In particular, mention the 4.0BSD and v8/Tahoe APIs that were supported until OpenBSD 5.4 and that matter for the evolution of RE functions in the BSD libc. Joint work with and OK jsg@. Regarding authorship of the v8 functions, Russ Cox writes near the end of https://swtch.com/~rsc/regexp/regexp1.html : "While writing the text editor sam in the early 1980s, Rob Pike wrote a new regular expression implementation, which Dave Presotto extracted into a library that appeared in the Eighth Edition. Pike's implementation incorporated submatch tracking into an efficient NFA simulation but, like the rest of the Eighth Edition source, was not widely distributed. Pike himself did not realize that his technique was anything new. Henry Spencer reimplemented the Eighth Edition library interface from scratch, but using backtracking, and released his implementation into the public domain. It became very widely used, eventually serving as the basis for the slow regular expression implementations mentioned earlier: Perl, PCRE, Python, and so on. (In his defense, Spencer knew the routines could be slow, and he didn't know that a more efficient algorithm existed. He even warned in the documentation, "Many users have found the speed perfectly adequate, although replacing the insides of egrep with this code would be a mistake.") Pike's regular expression implementation, extended to support Unicode, was made freely available with sam in late 1992, but the particularly efficient regular expression search algorithm went unnoticed." [...]