Re: What I Most Recently Learned in Perl, But Should Have Already Known

[gawatkins]

unless, once I learned it, I quit having to create complex if-else statements to decide if something did not happen. All languages should have an equivalent to unless

Thank you,
Greg W

[izut]

Continuing the if-else statements problem, the idiom I like most is:

my $function = 'a';
my %functions = (
    'a' => sub { ... },
    'b' => sub { ... },
);
$functions{$function}->();

It's amazing how this replace an entire switch or if-else statements.

[sfink]

I always run into the problem of the default case when I use that -- what if $function isn't a key in %functions? The error message "Undefined subroutine &main:: called" can be very difficult to figure out.

And the straightforward fix isn't all that pretty:

($functions{$function} || $functions{default})->();

But I admit that I still use it. With comments, if there is any chance that someone with a capacity to do me bodily harm might read the code.

[izut]

I think this way is prettier.

sub do_something {
    my ($function) = @_;
    $function = 'default' unless exists $functions{$function};
    $functions{$function}->();
}