Re: Getting for() to accept a tied array in one statement

[dave_the_m]

Is it an absolute requirement to have all the code within the while/for expression? I.e. is the following acceptable:

my $iter = TQDM::tqdm(1..10);

while (<$iter>) {
    print "got [$_]\n";
}

If so, then the behaviour you want is easily achieved using overloaded '<>'.

Otherwise, I think you need a custom iterator function, e.g.

sub iterate ($&) {
    my ($ary, $code) = @_;
    for (@$ary) {
        print "progress bar: $_\n";
        $code->();
    }
}

sub tqdm { bless [ @_ ] }

iterate tqdm(1..10), sub {
    print "got [$_]\n";
};

Dave.

[perlancar]

Yes, in this case the goal is on how easy it is to add a progress indicator to an existing code that uses for(). If a user has to change her for() to while(), that would count as less easy. It's akin in spirit to data dumping modules like XXX or Data::Dmp that returns its original argument so you can insert XXX or dmp just about anywhere in an existing Perl code.

Next step after I conquer for(), will probably move on to while(). :-) Yes, I'll be looking into overloading the diamond operator or tying filehandle.

[dave_the_m]

I don't think its possible in perl to write a function foo() that will allow any of the following in the way you want:

for (foo(list)) { ... }
while (foo(list)) { .... }
while (<foo(list)>) { .... }

assuming that for and while are the perl built-ins, and that you're not using source filtering or keyword plugins etc.

Dave.