On Sun 24 Jun 2018 at 19:49:25 +0700, Robert Elz wrote: > But the effect of that way of doing the specification is that the \ > which escapes magic characters in regular expressions does > not work inside [ ] (and the text is explicit about that - and correct) > which means the technique in the proposed revised posix text > about replacing " and ' quoting with \ doesn't work at all as intended > inside [ ] which is the case in test 97. But that can't be right > either, as then > > case - in [a\-z]) ... > > would not match, and whether you believe it should or not, > matching there is what all shells have done forever (that > is, the quoted - is a literal minus/hyphen/dash (whatever you > prefer to call it) and not the range indicator, where in a > regular expression that would be an 'a' and a range with > all chars from '\' to 'z'). Are we to assume that NetBSD's sh(1) manual page is correct? Since that clearly says that your example above should not match. Both in my 7.0 version, and the -current version (as seen on https://man-k.org/man/NetBSD-current/1/sh?r=1&q=sh#Shell_Patterns). Pretty much ~always, descriptions of character classes (including re_format(7)) have included words to the effect of To include a ``]'' in a character class, make it the first character listed (after the ``!'', if any). To include a ``-'', make it the first or last character listed. so the example should always have been case - in [az-]) ... if you want this to match. If your version matches, I'd call that a long-standing bug. I no longer have my printed Ultrix manuals, but I'd be surprised if they were different. Strangely, the Ex Reference Manual /usr/share/doc/reference/ref1/ex/reference.ps.gz on page 13 claims that a backslash SHOULD be used within  to escape characters, while the Vi/Ex Reference Manual /usr/share/doc/reference/ref1/vi/vi.ps.gz on page 10 refers to re_format(7). I suppose the former refers to the old encumbered BSD ex(1) while the latter says it refers to nvi(1). I found a V7 system (here: http://simh.trailing-edge.com/software.html)and a 2.11BSD system (I don'r remember where) and they did this (at least the V7 did; I didn't try all cases on 2.11BSD) # case - in [az-]) echo M;; *) echo X;; esac X # case a in [az-]) echo M;; *) echo X;; esac M # case z in [az-]) echo M;; *) echo X;; esac X # case z in [az]) echo M;; *) echo X;; esac M # case - in [a-z]) echo M;; *) echo X;; esac X # case - in [a\-z]) echo M;; *) echo X;; esac M I think that this shows that the trailing - isn't quite managed yet; the manpage indeed doesn't include the claim above phrasing about - and ], but the full description is just [...] Matches any one of the characters enclosed. A pair of characters separated by - matches any character lexi- cally between the pair. You would think that at the time the "- ] blurb" was added, it was supposedly because the code had changed and it was now true, but apparently not. But it would seem to indicate that it was meant to be true. -Olaf. -- ___ Olaf 'Rhialto' Seibert -- Wayland: Those who don't understand X \X/ rhialto/at/falu.nl -- are condemned to reinvent it. Poorly.
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