re-calling called functions

[opensourcer]

i have a package like this

package Tools;

sub new
{

    my ($caller, %args) = @_;
    my $caller_is_obj = ref($caller);
    my $class = $caller_is_obj || $caller;
    my $self = bless [], $class;
    return $self;    

}

sub DIRUtil
{
    my $self = shift;
    my ($path, $dirname, $option) = @_;

    if ($option eq "-c") {
        print $path."\n";
        chdir($path) or die "$!";
        mkdir ("xxx") or die "$!";
    }
}

here is the another package

package Agent

my $Utils = new Tools;

sub new
{

    my ($caller, %args) = @_;
    my $caller_is_obj = ref($caller);
    my $class = $caller_is_obj || $caller;
    my $self = bless [], $class;
    return $self;    

}


sub checkPackage
{
    my $this = shift;
    my $package = "SB";
    
    opendir(DIR, "D:/\box/\/\somthing/\SB") or $Utils->DIRUtil( "D:\/b
+ox\/something", "SB", "-c");     
}

here is the pl

$agent->checkPackage();

ok, what i'm doing here, if there'nt a folder called SB, then the DIRUtil will create one, what i want to know is after creating the folder, i want the DIRUtil to callback the invoking function, here it is checkPackage, i don't want to hard code the checkPackage inside the DIRUtil, is there any way to call back the invoking function ?, there may be other functions calling the DIRUtil. note: im aware of typo error or any mis-spelled words/sentence, and well any lexicals, plz ingore those errors. thanks.

[brian_d_foy]

Do you want to recall checkPackage so you get another chance to call opendir? Instead of gymnastics, just change checkPackage to check for the directory before it tries to open it. That way you don't have to re-dispatch to the calling method.

$Utils->DIRUtil( ... ) unless -d $dir;
opendir( ... );

[tsee]

Now, I suggest you never, ever, ever do this. A subroutine should not knwo about its calling context aside from what wantarray or the Want module provide. It's good for some fun hacking, but it boils down to being an evil hack. Rethink your algorithm.

That being said, it is possible in Perl. (No surprise, right?) It's just that it doesn't make any sense. Additionally, there are various corner cases which will break this.

The following code kind of does what you want. I suggest you read up on the caller() function. Also, you can't call the calling subroutine with its original arguments.

#!/usr/bin/perl
use strict;
use warnings;

sub _gotocaller {
    my $i = 2;
    while (1) {
        my ($pkg, $file, $line, $sub) = caller($i);
        if (not defined $pkg) {
            # no caller
            return;
        }
        elsif ($sub =~ /::__ANON__$/ or $sub eq '(eval)') {
            $i++;
        }
        else {
            no strict;
            goto &{"$sub"};
            die;
        }
    }
}

my $x = 1;
sub foo {
    print "foo: $x\n";
    if ($x < 10) {
        print join("|", caller(1)), "\n";
        _gotocaller() or die "shouldn't be reached if there was an enc
+losing subroutine!";
    }
}

sub bar {
    print "bar: $x\n";
    foo($x++);
}

bar();

Note that there are many things wrong with this code and I even thought about discarding the post when I looked at it again. To name just a few: symbolic references, goto &sub (which wouldn't be so bad if it wasn't used in conjunction with symbolic references and caller()), breaks for anonymous subs and eval's (or rather: calls the named sub that called the anonymous sub or eval block), etc.

Please, promise to not use this code. :/

Steffen

[GrandFather]

how about:

sub DIRUtil
{
    my $self = shift;
    my $caller;
    
    $caller = shift if ref $_[0];
    
    my ($path, $dirname, $option) = @_;

    while ($option eq "-c") {
        print $path."\n";
        chdir($path) or next;
        mkdir ("xxx") or next;
        return;
    } continue {
        # failure handling
        
        $caller->() if $caller;
        return;
    }
}

and

sub caller {
    $other->DIRUtil (&caller, ...);
}

Of course the failure handling in DIRUtil needs to exit early if directory creation failed.

BTW, $Utils = new Tools; is an error and the quoting in "D:/\box/\/\somthing/\SB" is bogus. /'s don't need to be quoted and as written it is the following letter that is needlessly quoted in any case. Using strictures (use strict; use warnings;) would pick up at least some of these problems for you.