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Sub Routine in a Variable ???

Posted on 2002-05-04
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Last Modified: 2010-03-05

I would like my Perl program to run a subroutine
that I have stored in a variable without having to
write it to disk. Is there a way to do that?The following doesn't work:

my $routine = "sub MySub{  print  \"hello from a sub in a variable!\";   }";

&$routine;

I get the following message:
Undefined subroutine &main::sub MySub{  print  "hello from a sub in a variable!";   } called at test.p line 8.

Again, I can't write it to disk and then use Require.
Thanks for any help!
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Question by:jgore
3 Comments
 
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by:baltman
ID: 6989897
I don't think it is possible. A subroutine needs to be defined somewhere before it can be executed.

Why would you want to do this? Is the subroutine always different? Can't you just put the subroutine in the script with lots of variables which you can change without saving anything on a disk? Maybe you could give some more details?

Again, variables can be placed in a subroutine, not the other way around. The subroutine needs to exist before it is executed....

BA
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Accepted Solution

by:
ozo earned 250 total points
ID: 6989930
my $routine = sub {  print "hello from a sub in a variable!";   };    

&$routine;
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Author Comment

by:jgore
ID: 6989944
This is more what I meant (This Works):

my $routine = "sub MySub{  print  \"hello from a sub in a variable!\";   }";
my ($routinename)=($routine =~ m/sub (.*?)\{/);
eval $routine;
&$routinename;

This way you can load routines into variables with nothing
being hard-coded. You could even make routines on-the-fly!
Can we say "A I ?" ;-)
I really just wanted a way to load perl code from a
text config file in which the code may be changed depending
on a seperate program (a Visual Basic config program). Now
my perl program can load perl code from a config file
and run it without having to know in advance anything
about the code (nothing hard-coded).
In any case, thanks everyone!
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