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

Not a good title but not sure how to describe it...or how to find it in CPAN...
I want to save some config options that are "on" or "off"
I want to save a logical expression of them and determine if it is true or false.
My ideas is to just use eval() and maybe safe::

For example I might save this in my config file.
(option1 && option2) || option3 And my program might define
option3, but not 1 or 2

I was thinking of s/// every option(1,2) with 0 and every option3 with 1 and then evaling it..

Would this be a good approach?

thanks

Replies are listed 'Best First'.
Re: and / or for config options
by DamnDirtyApe (Curate) on Aug 16, 2002 at 23:08 UTC

    If I understand you correctly, you want to do something like this:

    test_l.cfg 
    %config = (
    'proceed_with_x' => '( ($option1 && $option2) || $option3 )'
) ;

    [download]
    test_l.pl 
    #! /usr/bin/perl

use strict ;
use warnings ;
$|++ ;

our %config ;
do "test_l.cfg" ;

my ( $r, $option1, $option2, $option3 ) ;

# Case 1: Should pass.
( $option1, $option2, $option3 ) = ( 1, 1, 0 ) ;
$r = eval qq[$config{'proceed_with_x'}] ;
print "Case 1: " . ( $r ? "PASS" : "FAIL" ) . "\n" ;

# Case 2: Should pass.
( $option1, $option2, $option3 ) = ( 0, 0, 1 ) ;
$r = eval qq[$config{'proceed_with_x'}] ;
print "Case 2: " . ( $r ? "PASS" : "FAIL" ) . "\n" ;

# Case 3: Should fail.
( $option1, $option2, $option3 ) = ( 0, 1, 0 ) ;
$r = eval qq[$config{'proceed_with_x'}] ;
print "Case 3: " . ( $r ? "PASS" : "FAIL" ) . "\n" ;

__END__

    [download]

    _______________
    DamnDirtyApe 
    Those who know that they are profound strive for clarity. Those who
would like to seem profound to the crowd strive for obscurity.
            --Friedrich Nietzsche
[reply]
[d/l]
[select]
      makes sense, thanks!
[reply]

Back to Seekers of Perl Wisdom