On Fri, 4 Jan 2002, Connie Chan wrote:
> I 've read some doc about the difference of require and use...
> but I don't know what exactly that all means ?... what is run
> time and what is compile time ? all I hope to know is.....
> which one will be faster and cost the minium loading vs time &
> to the system, for a 1 time process.
>
One cool thing about 'require' is that you can read in files with it
(like config files), that may have been created with real perl data
structures, like Data::Dumper.
Example:
create a mysql.config file:
#!/usr/bin/perl -w
use strict;
use Data::Dumper;
my $href = {
db_database_dsn => 'dbi:mysql:database=FOO;host=localhost',
db_user => 'foo',
db_pass => 'bar'
};
open (F, ">mysql.config") or die "couldn't open file: $!";
print F Dumper $href;
----
then run this script and it creates a file that looks like this:
$VAR1 = {
'db_user' => 'foo',
'db_pass' => 'bar',
'db_database_dsn' => 'dbi:mysql:database=FOO;host=localhost'
};
----
then (and this is the cool part), you can 'require' this file and
assign it to a scalar (which actually becomes a hash_ref because that's
what your data structure is:
#!/usr/bin/perl -w
use strict;
#require 'eval's the file
my $config = require "mysql.config";
#now $config is a hashref with your config directives
print $config->{'db_user'};
print $config->{'db_pass'};
this of course one small useful feature of 'require'. I would say, in
general though, you want to use 'use'.
And of course, read the perldocs on both :)
Chris
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