Getting same output doing pattern matching

tariqahsan has asked for the wisdom of the Perl Monks concerning the following question:

I am running the following script using data from a configuration file. For some reason unknown to me same values are returned instead of different ones as shown in the bottom. Can someone explain what I am doing wrong?
Thanks.

The config file myconfig.cfg:

CCBFile|NDM|/u1/cdunix/work/blprobr1|S${TODAY}.00?|${TODAY}CCB
[download]

The script -

#!/apps/bin/perl -w

$TODAY = "20030518";
$config_file = "myconfig.cfg";

open (CONFIG, "$config_file") || die "Can't open $config_file for read
+ing : $!\n";
while ( defined ($_ =  <CONFIG>) )
{<br>
    my($job,$type,$dir,$file,$pattern) = split(/\|/,$_);
    my $val1 = file_eval($file);
    my $val2 = file_eval($pattern);
    print "val1 : $val1\n";
    print "val2 : $val2\n";
}
close(CONFIG);

sub file_eval
{
    my ($value) = @_;

    $match = '([0-9A-Za-z._%?#]*)(\$\{\w+\})([0-9A-Za-z._%?#]*)';
    if ( $value =~ /$match/g )
    {
        print "\nvalue is : $value\n";
            ($p1,$p2,$p3) = /$match/;
            print "\n p1 is $p1\n";
            print "\n p2 is $p2\n";
            print "\n p3 is $p3\n";
            $px = eval "$p2";
            $filex = $p1 . $px . $p3;
            print "\n filex is $filex\n";
    }
    return $filex;
}
[download]

The output -

value is : S${TODAY}.00?

 p1 is S

 p2 is ${TODAY}

 p3 is .00?

 filex is S20030518.00?

value is : ${TODAY}CCB

 p1 is S

 p2 is ${TODAY}

 p3 is .00?

 filex is S20030518.00?
val1 : S20030518.00?
val2 : S20030518.00? <- should be 20030518CCB
[download]

Comment on Getting same output doing pattern matching Select or Download Code

Replies are listed 'Best First'.
Re: Getting same output doing pattern matching by Abigail-II (Bishop) on May 21, 2003 at 22:41 UTC
It's the following line: `($p1,$p2,$p3) = /$match/;` [download] This matches against `$_`, which doesn't change between calls to `file_eval`. Since you have already matched, you could just do: `($p1, $p2, $p3) = ($1, $2, $3);` [download] Abigail	[reply] [d/l] [select]
Re: Re: Getting same output doing pattern matching by tariqahsan (Beadle) on May 22, 2003 at 04:31 UTC
Abigail, Thanks a lot! It worked.	[reply]
Re: Getting same output doing pattern matching by pzbagel (Chaplain) on May 22, 2003 at 06:51 UTC
On a side note, the error checks you do on the CONFIG filehandle as you read it in are already done by perl automagically. `#The line: while ( defined ($_ = <CONFIG>) ) #can be simplified to: while(<CONFIG>)` [download] When you use the <> in the conditional of a while loop, perl automatically sets the $_ variable to be the input record it read from the file. It also checks that it is defined() for you so you don't have to. Just a little sweet syntactic sugar for you.	[reply] [d/l]