use Try::Tiny;
while (my @parsed = &parseInput) {
    &dispatch(@parsed);
}

sub parseInput {
    my $inp = <>;
    chomp $inp;
    my @parsed = split $inp;
    return () if $parsed[0] eq `q`;
    return @parsed;
}

sub dispatch {
    my $cmd = shift;
    try { eval( '&' . $cmd . '(' . join ',', @_ . ');' ); }
    catch { print STDERR "Unrecognised command $cmd\n"; }
    # the above is a non-GUI example which would need adaptation                                                              
}

# and add a sub xxx for each command xxx