strange behavior of indexed list of globs

[jabowery]

$|++;
for (1..10){
        $pid[$_]=open($fh[$_],"-|");
        next if $pid[$_];
        print;
        exit(0);

}
foreach my $i (1..10){
        my $fh=$fh[$i];
        while(<$fh[$i]>){
                print "'$_'";
        }
        close $fh[$i];
}

outputs:

'GLOB(0x2535298)''GLOB(0x25352e0)''GLOB(0x2535418)''GLOB(0x2541e38)''G
+LOB(0x2541ec8)''GLOB(0x25669d8)''GLOB(0x255ead8)''GLOB(0x2542420)''GL
+OB(0x25523a8)''GLOB(0x2542dc8)'

but change $fh[$i] after its first occurance to $fh and it outputs:

'1''2''3''4''5''6''7''8''9''10'

[davido]

Are you asking about the behavior of <$simple_scalar> versus <$more[$complex]>? That's a readline versus a glob. perlop says:

If what's within the angle brackets is neither a filehandle nor a simple scalar variable containing a filehandle name, typeglob, or typeglob reference, it is interpreted as a filename pattern to be globbed, and either a list of filenames or the next filename in the list is returned, depending on context. This distinction is determined on syntactic grounds alone. That means <$x> is always a readline() from an indirect handle, but <$hash{key}> is always a glob(). That's because $x is a simple scalar variable, but $hash{key} is not--it's a hash element. Even <$x > (note the extra space) is treated as glob("$x ") , not readline($x).

The feature is probably going to go down already recorded in history as one of Perl's warts. :) And the confusion that the angle brackets operator leads to is the primary motivation behind Perl Best Practice's advice to "Use glob, not <...>" (Globbing, page 167).

[jabowery]

Thanks for the heads up. Perl does what I think it will enough of the time, without reference to documentation, that tolerating its few documented warts is worth it.