#!/usr/bin/perl -w 
use strict;

sub func_a_1 {
      print "A 1\n";
}

sub func_a_2 { 
      print "A 2\n";
}
sub func_b_1 { 
      print "B 1\n";
}

sub func_b_2 {
      print "B 2\n";
}

for my $n( qw/ a b /){
     for my $i (1..2) { 
          eval "&func_$n_$i()"
     }
}