"Can't use string ("a") as a subroutine ref while "strict refs" in use at line [eval { $result .= &{$_}(@time); };]"

##</code><code>##

my %method_map = (a => sub { ... }, A => sub { ... } );
my $token = 'a'; # or 'A', 'D', etc.
my $result .= $method_map{$token}->(@args);