using variables in late contexts?

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

Hello,
I am trying to have my script go through some
variables without the variable names being there until
the code is run. I think this is late-binding but i am
not entirley sure. Here is what i want to do.

my result_temp="";
foreach my $test (@testarray)
{
     if(!defined($result_temp = $session->getrequest(
             -varbindlist => ['$'.%cmd_table{$test}]
)))
{
print ("error in session:%s", %cmd_table{$test});
$result_temp="error";
}
push @RESULTS, @result_temp;
}
[download]

What the code would look like that is late-bound is

-varbindlist => [$myvariable]
[download]

but what will the perl interpreter see?
cause the variable names are all in cmd_table hash
referenced by a number (where test_array is a array of
command numbers. Is there a way to so what i want?
Thanks.
Enigmae

Comment on using variables in late contexts? Select or Download Code

Replies are listed 'Best First'.
Re: using variables in late contexts? by Eimi Metamorphoumai (Deacon) on Nov 26, 2002 at 22:46 UTC
Although the other replies will probably work, the idea is probably misguided. There are very, very few places where it's a good idea to use variables for variable names, and this isn't one of them. Try to rewrite your code using a hash instead. See mjd's excellent post for more information.	[reply]
Re: using variables in late contexts? by robartes (Priest) on Nov 26, 2002 at 22:37 UTC
Your code should work, except that you need to replace: `%cmd_table{$test}` [download] by `$cmd_table{$test}` [download] You are refering to the value of a hash entry, not the hash itself, that's why you need $. Oh, and there is no need for the @testarray (at least not in this snippet): just loop over the keys of %cmd_table, as in: `foreach $test (keys %cmd_hash) { # do your thing }` [download] Hope this helps. CU Robartes-	[reply] [d/l] [select]
Re: using variables in late contexts? by jreades (Friar) on Nov 26, 2002 at 22:34 UTC
Let me see that I have this straight. You want your code to 'look' like: `-varbindlist => [$myvariable]` [download] Where the input would be: `-varbindlist => [${$some_variable}]` [download] And the input $some_variable would be derived from a value in %cmd_table. In that case, I think that the answer is simply: `my @RESULTS = (); my $test; foreach $test (@test_array) { my $temp = $session->getrequest( -varbindlist => [${$cmd_table{$test}}] ); unless (defined $temp) { print("Error in session: %s", $cmd_table{$test}); push @RESULTS, "error"; } else { push @results, $temp; } }` [download] Reformat for personal style. Also note that this will probably cause some issues if you use strict since you're interpolating variable names which could result in various security issues.	[reply] [d/l] [select]


"be consistent"
	PerlMonks