I don't know how you made that determination but I think something else is happening. The following code shows that the string only gets evaled with the ref itself is called.

use strict;
use warnings;

my $code = 'print "Hello\n"';

print "BEFORE\n";
my $test;
$test->{a} = sub { eval $code};
print "BETWEEN\n";
$test->{a}->();
print "AFTER\n";
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Outputs

C:\Perl\test>perl order_sub.pl
BEFORE
BETWEEN
Hello
AFTER
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You can see the hello is only printed with the ref is executed and not when it is defined.

Your code works. I am still having a problem however because I am looking for the $dfv object to be passed to the sub {}. I find it passes the variable but it is not passing the DFV object.

I hate trying to figure out these little quirks!

First, make sure you do

use strict;
use warnings;
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in your code if you aren't already.

To be honest, I have not looked into this in detail, but have a look at the $code =<<"END" part. The double quotes will make your string be interpolated, which mean while assigning to $code your variables $dfv etc will be expanded, and may well be undefined. Thus eval might see only my = shift;, which doesn't compile. eval fails and sets $@ aka $EVAL_ERROR, which you should check for.

Use single quotes around END, or escape everything that might be interpolated.

Also, you might consider moving the semicolon after the END up, that is:

$code = <<'END';
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I hope I got it somewhat right, and it helps a bit.

The actual program is 500 lines long, this is just a sample code to relay the concept, not emulate a complete script.

my $profile;
{
        my $var = eval '33';  # or just  my $var = 33
                              # or       my $var = setme_at_runtime();

        $profile = { my_name => sub {  ($var =~ /\d+/) ? 1: return  }
                   };
}

my $fun = $profile->{my_name};

print $profile->{my_name}->( );
print $profile->{my_name}->('a');
print $profile->{my_name}->( 22 );
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First thing in my head is that this may be an XY Problem. I think. What is it that you're trying to solve by using a dynamic code reference?

The reason why I'm not sure is that I do know of uses for dynamic code references - I've done it many times when I'm using input from files and I can conceptualise things better as embedding the data in the code than any other way. But this doesn't appear that way (so far).

That said, the eval won't happen until it is called by DFV. But I'm not really sure that's what you want.

$coderef = eval "sub { $code }";
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Check the return value of the eval and/or $@, if the eval fails and returns undef, you must have had a syntax error.

NOTE, I did not correctly read the parent post! The parent was absolutely correct.

Sorry, this does not work, you are doing what I did originally, which was

sub { $code };
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Which treats $code as a string instead of perl code. This of it this way,

eval sub { 'print "I love perl\n;" }
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this will not return an error and still does nothing except return the the string I just had in there. The eval has to be in the sub for the string.

I think you did something wrong, perhaps you used single quotes instead of double quotes. As it is in my code, the string is inserted in the sub definition before it is evalled. Try this:

$code = 'print "I love perl\n";';
$coderef = eval "sub { $code }";
$coderef->();
print "Don't believe me?\n";
$coderef->();
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Result:

I love perl
Don't believe me?
I love perl
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Why not just create the subroutine reference like this:

my $code = sub {
    my $dfv = shift;
    my $var = shift;

    return $var !~ /\d+/ ? 1 : 0;
};

my $profile = {
    required => [qw/my_name/],
    constraint_methods => {
        my_name => $code,
    },
};
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No need to create a string first.