Re: priority problem of ":|" and ":*"

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Dec 26,  7:11am, Han Pingtian wrote:
}
} >     % a1=(a b c);a2=('a b c');print "${#a1:|a2}"
} >     3
} > 
} > in this, the priority should be "5 Double-quoted joining" first, then "7
} > modifiers", then "9 length". So 'print "${#a1:|a2}"' should output 0 I
} > think. And the ":*" has the same problem. 

Hmm.

% a1=(a b c); print "${#a1}" :"${a1}":
3 :a b c:

Plainly if length were applied after double-quoted joining, the above
should print 5 rather than 3.  As I'm pretty sure this hasn't changed
*ever*, it must be that the documentation is wrong, not that :| has the
wrong priority.

And in fact poring through the code it appears that rule 5 double-quoted
joining is explicitly SKIPPED when the length is requested:

    if (isarr) {
        if (nojoin)
            isarr = -1;
        if (qt && !getlen && isarr > 0) {
            val = sepjoin(aval, sep, 1);
            isarr = 0;
        }
    }

"qt" there means double-quoted, but "getlen" means the "#" was seen.  So
when evaluating length, we do not remove arrayness.

} For the ":*", we have this result:
} 
}     % a1=(a b c);a2=(a b c);print "${#a1:*a2}"
}     3

This is consistent with the above.

I admit that this is not intuitive when applying operations to the members
of the array, but it's the way #, ##, %, %%, and :# have always worked, so
it's a bit late to change it and arguably worse to make it different for
:| and :*.  (My sympathies if anyone's mail reader is too clever by half
and renders a lot of that as emoticons.)