Re^2: print_r

[mwah]

grinder:  This will recurse endlessly until the heat death of the universe or you run out of swap, whichever comes first. Then again, perhaps the PHP implementation does as well.

PHP's print_r (522) does indeed detect recursion after the first loop:

<?php
 $r1 = array( 1 );
 $r2 = array( 2, &$r1 );
 array_push( $r1, &$r2 );

 print_r($r1);
?>

This will result in the following output:

(
    [0] => 1
    [1] => Array
        (
            [0] => 2
            [1] => Array
                (
                    [0] => 1
                    [1] => Array
 *RECURSION*
                )

        )

)

Regards

mwa

[Anonymous Monk]

recursion check:

sub print_r {
    
    my $level="";
    my @level_index=();
    my @print_r_Recursion=();
    print_rec (@_);
    undef @level_index;
    undef @print_r_Recursion;
    undef $level;
    
    sub print_rec {

        if ( ! defined $level ) { $level = 0 };
        if ( ! defined @level_index ) { $level_index[$level] = 0 };

        for ( @_ ) {

            my $element = $_;
            my $index   = $level_index[$level];
            
            if (ref($element) eq 'ARRAY' || ref($element) eq 'HASH'){
                my $loop=0;
                for (@print_r_Recursion){
                    if (($element."") eq ($_."")){
                        $loop=1;
                        last;
                    }
                }
                if ($loop==1){
                    print "\t" x $level . "[$index] => ". ref($elem
+ent) ." *recursion*\n";
                    next;
                }
                push @print_r_Recursion,$element;
            }
            
            print "\t" x $level . "[$index] => ";

            if ( ref($element) eq 'ARRAY' ) {
                my $array = $_;

                $level_index[++$level] = 0;

                print "(Array)\n";

                for ( @$array ) {
                    print_rec( $_ ); 
                }
                --$level if ( $level > 0 );
            } elsif ( ref($element) eq 'HASH' ) {
                my $hash = $_;

                print "(Hash)\n";

                ++$level;

                for ( keys %$hash ) {
                    $level_index[$level] = $_;
                    print_rec( $$hash{$_} );
                }
            } else {
                print "$element\n";
            }

            $level_index[$level]++;
        }
    }
}