If you use next, there is no need to use else: the code after next can only be reached if the condition was not true.

You do not want to use eval BLOCK to catch exceptions. You want to use eval STRING to evaluate a constructed code. You should include the assignment in the code, though: 

#!/usr/bin/perl
use warnings;
use strict;

my $sql_var_hr;
$sql_var_hr->{col_name} = 'column_name';
my $sql = get_sql($sql_var_hr);


sub get_sql {
    my ($vars) = @_;
    my $sql;

    while (my $iline = <DATA>) {
            next if $iline =~ /^#/;
            $sql .= $iline;
    }
    print "pre_eval: $sql\n";
    eval '$sql = "' . $sql . '"' or warn $@;
    print "post_eval: $sql\n";
    return $sql;
}

__DATA__
select $vars->{col_name} from schema.table
select $$vars{col_name} from schema.table

[download]
Using "templates" might solve lots of problems this naïve approach might cause.
لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Re: Evaling Strings in Subs for Hashref Variable Names to Values by choroba
in thread Evaling Strings in Subs for Hashref Variable Names to Values by theleftsock

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