From: Peter Stephenson <p.w.stephenson@ntlworld.com>
To: zsh-workers@zsh.org
Subject: Re: behavior of test true -a \( ! -a \)
Date: Thu, 21 Mar 2024 11:29:39 +0000 (GMT) [thread overview]
Message-ID: <1507569659.5899391.1711020579178@mail.virginmedia.com> (raw)
In-Reply-To: <20240321110444.GC164665@qaa.vinc17.org>
> On 21/03/2024 11:04 GMT Vincent Lefevre <vincent@vinc17.net> wrote:
> On 2024-03-21 10:28:16 +0000, Peter Stephenson wrote:
> > I haven't had time to go through this completely but I think somewhere
> > near the root of the issue is this chunk in par_cond_2(), encountered at
> > the opint we get to the "!":
> >
> > if (tok == BANG) {
> > /*
> > * In "test" compatibility mode, "! -a ..." and "! -o ..."
> > * are treated as "[string] [and] ..." and "[string] [or] ...".
> > */
> > if (!(n_testargs > 2 && (check_cond(*testargs, "a") ||
> > check_cond(*testargs, "o"))))
> > {
> > condlex();
> > ecadd(WCB_COND(COND_NOT, 0));
> > return par_cond_2();
> > }
> > }
> >
> > in which case it needs yet more logic to decide why we shouldn't treat !
> > -a as a string followed by a logical "and" in this case. To be clear,
> > obviously *I* can see why you want that, the question is teaching the
> > code without confusing it further.
>
> Perhaps follow the coreutils logic. What matters is that if there is
> a "(" argument, it tries to look at a matching ")" argument among the
> following 3 arguments. So, for instance, if it can see
>
> ( arg2 arg3 )
>
> (possibly with other arguments after the closing parenthesis[*]), it
> will apply the POSIX test on 4 arguments.
>
> [*] which can make sense if the 5th argument is -a or -o.
I suppose as long as we only look for ")" when we know there's one to
match we can probably get away with it without being too clever. If
there's a ")" that logically needs to be treated as a string following a
"(" we're stuck but I think that's fair game.
Something simple like: if we find a (, look for a matching ), so blindly
count intervening ('s and )'s regardless of where they occur, and then
NULL out the matching ) temporarily until we've parsed the expression
inside. If we don't find a matching one treat the ( as as a string.
pws
next prev parent reply other threads:[~2024-03-21 11:30 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-21 10:07 Vincent Lefevre
2024-03-21 10:28 ` Peter Stephenson
2024-03-21 11:04 ` Vincent Lefevre
2024-03-21 11:29 ` Peter Stephenson [this message]
2024-03-21 12:18 ` Vincent Lefevre
2024-03-21 12:25 ` Peter Stephenson
2024-03-21 19:06 ` Bart Schaefer
2024-03-22 5:02 ` Bart Schaefer
2024-03-25 16:38 ` Peter Stephenson
2024-03-25 17:36 ` Bart Schaefer
2024-04-03 13:59 ` Vincent Lefevre
2024-03-21 17:39 ` Bart Schaefer
2024-03-23 21:48 ` Bart Schaefer
2024-03-23 22:20 ` Vincent Lefevre
2024-03-23 22:41 ` Bart Schaefer
2024-03-23 23:33 ` Lawrence Velázquez
2024-03-24 0:14 ` Bart Schaefer
2024-03-24 2:52 ` Lawrence Velázquez
2024-03-25 10:23 ` Vincent Lefevre
2024-03-25 15:21 ` Bart Schaefer
2024-03-25 17:33 ` Vincent Lefevre
2024-03-25 17:43 ` Bart Schaefer
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