Use a dispatch table to map your categories (A .. E) to functions and look for you category in $func_com.

Something like...

my %dispatcher =
(
 A => \&func_A,
 B => \&func_B,
 C => \&func_C,
 #etc
);

my @temp_results;
for my $cat ( 'A' .. 'E' )
{
    push @temp_results, [ $dispatcher{$cat}->( @some_val ) ]
        if $func_com =~ m/$cat/; # index is better
}
push @all_res, \@temp_results;

# Do something with @all_res
[download]