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Perl eval problem

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# 1  
Old 03-08-2013
Perl eval problem
Hello All,

I am trying to use perl eval in a complex code and below given is a pseudo code of my logic.

Here $result evalutes to empty.


Please help.How should I retrieve of $t where $f just hold the name of varaible i.e t

Code:
$t=10;
$f='$t';
$result=eval "\$$f";
print "$result\n";

# 2  
Old 03-08-2013
Code:
$t=\10;
$f='$t';
$result=eval "\$$f";
print "$result\n";

OR
Code:
$t=10;
$f='t';
$result=eval "\$$f";
print "$result\n";

You would also need to worry about the eval string's scope.
Last edited by elixir_sinari; 03-08-2013 at 02:40 PM..
# 3  
Old 03-08-2013
The usual thing to do in Perl is, instead of looking up variable names, keep a hash to look up values in.

Code:
my %hash=( "key" => "value",
                               "another key" => "another value" );

print "value for var 'key' is ",$hash{key},"\n";

This is also much more secure than eval. Someone could put `rm -Rf ~/` in your eval and it would do it!
Last edited by Corona688; 03-10-2013 at 03:26 PM..
# 4  
Old 03-11-2013
Code:
perl -e '$t=10;
$f=q($t);
$result=eval $f;
print "$result\n";'

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