Hello, for your possible interest. Steffen Nurpmeso via austin-group-l at The Open Group wrote in <20240916152314.Do4nw6pA@steffen%sdaoden.eu>: |Steffen Nurpmeso wrote in | <20240916150420.FRIEjRZF@steffen%sdaoden.eu>: | ... ||Having said that, Arnold Robbins of GNU awk quite enthusiastically ||posted somewhere (i cannot find nowhere where he did, actually) ||that he is about to change the implementation of its (regex of ||GNUlib) regular expression engine (alternatively) to a newly ||written one [2], ie, from Mike Haertel, famous for his ||implementation of GNU grep. He has opened an issue for itself in ||order to support "non-greedy repetition operators" already [3]. || || [2] https://github.com/mikehaertel/minrx || [3] https://github.com/mikehaertel/minrx/issues/12 | |In his ALGORITHM.txt he by the way says | | ... | There is one potential refinement in the translation scheme that has not | yet been discussed that pertains to the associativity of concatenation. ... | It turns out the POSIX standard is ambiguous about this situation. | The grammar in the standard for concatenated regular expressions is a | left-associative grammar. However, there is an example in the rationale | (not officially part of the standard...) that assumes concatenation is | is right-associative.
I was about to open a clarification issue, but could not find the quoted rationale, yet i got my hands on Mike Haertel's email address and thought i ask him. He was so nice to answer and he says that the above arose from memory from something read in the past, and that he is unable to find the exact quote now. So, he is about to search some more, and says he will revise the above paragraph in case he cannot find it. Since i track his repository either a clarification issue will be opened, or not. Ciao, --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)
