Hi. Paul Eggert <egg...@cs.ucla.edu> wrote:
> On 7/15/21 1:48 PM, Arnold Robbins wrote: > > The regexp used there, ".^", to my mind should be treated as invalid. > > No, that regular expression is valid because "." matches newline in > POSIX EREs. So the "." matches a newline, and the following "^" matches > the start of the next line. Bruno Haible <br...@clisp.org> wrote: > > No, that regular expression is valid because "." matches newline in > > POSIX EREs. > > And if you don't like this, you need to remove the RE_DOT_NEWLINE flag from > the value that you pass to re_set_syntax. Dot matching newline isn't the issue here. It's ^ matching in the middle of a string. For my purposes, ^ should only match at the beginning of a *string* (as $ should only match at the end of a string). I haven't rechecked POSIX, but this is how awk has behaved since forever. (And how I've documented things in the manual, also since forever.) For RS, gawk treats the concatenation of the input files as one long string, so ^ should only match at the very beginning, and $ at the very end. But even for strings the GNU regex routines seem to get it wrong: $ cat y.awk BEGIN { data = "a.^b\na.^b\n" gsub(/.^/, ">&<", data) print data } $ mawk -f y.awk # gets it right IMHO a.^b a.^b $ nawk -f y.awk nawk: syntax error in regular expression .^ at source line number 3 source file y.awk context is gsub(/.^/, ">&<", >>> data) <<< $ ./gawk -f y.awk a.^b> <a.^b> < Is there some way I can get the regex routines (and dfa) to relate to ^ and $ as relative to the *string* and not the *line*? Thanks, Arnold