[Purdue-pm] Perl 5 Dispatch Tables

Mark Senn mark at purdue.edu
Tue May 28 17:20:45 PDT 2019

> I'm not sure how a typical dispatch table is violating DRY.
> [... -mark]
> sub create_dispatch_table ($config) {
>   my $dispatch = {
>   'thing_one' => \&thing_one,
>   'thing_two' => \&thing_two,
>   };
>   return($dispatch);
> }
> [... -mark]

    The DRY Principle: Don't Repeat Yourself
    DRY stand for "Don't Repeat Yourself," a basic principle of software
    development aimed at reducing repetition of information.

>From my earlier message:
    In short, I don't use conventional dispatch tables because they
    violate the don't repeat yourself principle.  I'm only dispatching
    to subs based on trusted information and the core of the idea is

I should have written
    I only use dispatch tables to dispatch to non-anonymous subs
    based on trusted information.

To me,
    my $dispatch = {
    'thing_one' => \&thing_one,
    'thing_two' => \&thing_two,
is an example of repetition.  For the case I wrote about, this code
is not needed.  Since it's not needed I don't use it---it's just
more code to support.  Given a word w, I always call a subroutine
whose name can be computed from w.  In other words, I don't need to do
    'thing_one' -> \&some_name_that_cannot_be_be computed_from_thing_one


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