From: Trans <transfire@...>
Date: 2008-03-03T06:40:44+09:00
Subject: Re: BlockChainable 0.0.1 released



On Mar 2, 11:31 am, Drew Olson <olso...@gmail.com> wrote:
> BlockChainable is a module to aid in the creation of Domain Specific
> Languages using block structure. By including BlockChainable into your
> classes, you will be able to instantiate that class using the class name
> itself, followed by any parameters to be passed to initialize, followed
> by a block to be executed within the instantiated class.
>
> BlockChainable also allows methods to search up the chain of classes,
> meaning that although a block is executed in the scope of the
> instantiated class, any methods not found in the class but found in a
> class "up-scope" will be called successfully on the up-scope class. This
> chaining of method calls allows you to assert values within the blocks
> as well as calling any other methods from "up-scope" classes.
>
> I know, I know, I need a better description :) Take a look at a usage
> example more some simple ideas on using BlockChainable. And afterwards,
> install it like so:

He he. You could use Zope terminology, "acquisition" :)

> sudo gem install block-chainable
>
>   # a simple dsl for creating classroom rosters and printing them out.
> code can be found in the
>   # example directory of BlockChainable.
>
>   require 'block_chainable'
>
>   # first, define our roster
>   class Roster
>     include BlockChainable
>
>     def initialize(subject)
>       @subject = subject
>       @students = []
>     end
>
>     def add_student_to_roster student
>       @students << student
>     end
>
>     def print_roster
>       puts "Roster for #{@subject}:"
>       @students.each{|s| puts "  #{s}"}
>     end
>   end
>
>   # next, define our student. the only tricky part here is
> add_to_roster, which calls
>   # the method add_student_to_roster, which is actually defined on the
> Roster class.
>   # BlockChainable will automatically send this method to the Roster
> class with the
>   # Student instance as a parameter.

So I take it that the Student class does'nt work on it's own because
it would not be able to find #add_student_to_roster --sort of like the
opposite of a class using a mixin and not providing a prerequisite
method.

This is an interesting library. I'm curious to see the underlying meta-
programming.

T.