Re: Making hash from two arrays

[John W. Krahn]

Lawrence Statton wrote:
I was *JUST* lecturing my student on hash-slices Monday ... 

Part of that lecture....
Passing named paramters, implemented as a hash, is a popular style.
Look at all of Perl/Tk, for example.  For systems where you might pass
dozens of parameters to a method (or subroutine), and you want each of
those values to have reasonable defaults, you really can't beat it.
An example :
#!/usr/bin/perl
use strict; 
use warnings; 

sub frobitz {
    my (%opt) = @_ ;
    $opt{name} = 'blueberry' unless exists($opt{name}); 
    $opt{color} = 'blue' unless exists($opt{color}); 
    $opt{texture} = 'medium' unless exists($opt{texture}); 
    $opt{price} = 30 unless exists($opt{price}); 
    
    # ... do something useful 
}

frobitz ( name => 'banana',
	  color => 'yellow',
	  texture => 'soft',
	  price => 5 ); 
The way I've seen that done sometimes is like this:
sub frobitz {
    my %opt = (
        name => 'blueberry',
        color => 'blue',
        texture => 'medium',
        price = 30,
        @_
        );
    # ... do something useful
}
The trailing keys and values in the list override the defaults if they are 
present.  And of course that won't work for scalars or arrays.

John
--
use Perl;
program
fulfillment
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