From: Leslie Viljoen <leslieviljoen@...>
Date: 2008-02-19T16:43:34+09:00
Subject: Modules: The Secret H method

Hello!

I am having a hard time using modules. It seems that to successfully
use one, you
need to know all sorts of obscure things about the environment that
the module expects.

For example, I want to use Webby::Helpers::UrlHelper. This module
refers to a @pages
variable that I have to provide in the class that "include"s the
module. That is not so
hard, but I can only find that requirement via experimentation. If I
provide the @pages
variable in my class, I then find that the module refers to a method
"h". I know rails
has a helper method "h", but cannot otherwise find one, despite all my
grep -ir "def h"  on the entire standard library and all gems (well,
"rack" has such
a method too, but Webby never uses rack AFAIK).

So is this how people normally use modules, or am I doing something stupid?
How is anyone supposed to know the possibly highly complex
requirements of a module
- or does it fall to documentation again?

There's a similar problem with calling *any* methods that take
parameters in Ruby -
how can you get a list of all the methods that will be applied to the
object you passed
in? Either the documentation says "pass in a string" and then you are expected
to pass in something that responds to ALL of string's methods, or the
documentation
must list every method applied, along with its signature. All the
documentation I have
seen uses option A: it mentions the class to pass in. Which renders
duck-typing shot,
unless I descend from that class perhaps?

BTW: where can I find the secret "h" method?

Les