Shell Programming and Scripting

is it possible to use eval to create constants in perl? i cannot seem to get anything to work, and my searches are turning up little to nothing. an example of what i am trying to do is this:

2 arrays:

array 1: 'FOOD','NUMBER','OS'
array 2: 'pizza','two','unix'

loop through the arrays and assign 2 to 1, 1 being the constant name. do i have to cave in and hardcode array 1?

thanks.

Do you mean something like this?

Code:

#!/usr/bin/perl

@foo=('FOOD','NUMBER','OS');
@bar=('pizza','two','unix');

foreach $foo_val ( @foo ) {
  eval "\$$foo_val = @bar[$count]";
  ++$count;
}
print "\$FOOD IS $FOOD\n";
print "\$NUMBER IS $NUMBER\n";
print "\$OS IS $OS\n";

Cheers
ZB

hey bob,

not quite; although i may end up using that method. i was trying to eval the variable names and values into a use constant $VAR_NAME => $VAR_VAL; type deal. after my efforts yesterday, i'm guessing it cannot be done, but if anyone has any further ideas, they are appreciated

You can create constants dynamically using the "use constant", but the whole thing (initialization of constant-value hash) needs to be in a BEGIN {} block, before the rest of the script is executed.

This is good for initializing constants from config file or something like that before the script starts, but after the script has started execution there is no way to create real constants anymore.

swell. this sets me on the proper path. thanks guys.

#!/usr/bin/perl

@foo=('FOOD','NUMBER','OS');
@bar=('pizza','two','unix');

foreach $foo_val ( @foo ) {
eval "\$$foo_val = @bar[$count]";
++$count;
}
print "\$FOOD IS $FOOD\n";
print "\$NUMBER IS $NUMBER\n";
print "\$OS IS $OS\n";

exit))