Re: behavior of test true -a \( ! -a \)

[Vincent Lefevre <vincent@vinc17.net>]

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.

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Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
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