From: Trans <transfire@...>
Date: 2006-07-23T23:40:10+09:00
Subject: Re: Meta-Meta-Programming, revisited


Erik Veenstra wrote:
> > I'm not sure the Array abuse is needed if you limit the
> > arguement to the array itself, eg. don;t splat it whencalling
> > the block
>
> True. I did that before. But receiving |*args| in blocks is so
> common (for me), that I was typing it again and again,
> introducing bug after bug. That's why I introduced this
> Array-parameter-thing.

I see. But |*args| does work just so long as you don't want to _change
the args_, doesn't it?

> > I'll have to look at the Object abuse again and get back to
> > you.
>
> Please.

Okay. Looking at your "Object" example:

    require "ostruct"
    class Foo < Struct.new(:aa, :bbb)
      post_condition(:initialize, Object) do
        line = caller.select{|s|
s.include?(__FILE__)}.shift.scan(/\d+/)[-1]

        puts "An object of class #{self.class} has been created."
        puts "The arguments are: @aa=#{aa} and @bbb=#{bbb}."
        puts "The object has id: #{__id__}."
        puts "It's done on line: #{line}."
        puts
      end
    end

So you're confining the context of excution, shutting out the defining
closure. Correct? It seems reasonable, though couldn't one do that on
their own if they wanted? Eg.

    class Foo < Struct.new(:aa, :bbb)
      post_condition(:initialize) do
        instance_eval do
          line = caller.select{|s|
s.include?(__FILE__)}.shift.scan(/\d+/)[-1]

          puts "An object of class #{self.class} has been created."
          puts "The arguments are: @aa=#{aa} and @bbb=#{bbb}."
          puts "The object has id: #{__id__}."
          puts "It's done on line: #{line}."
          puts
        end
      end
    end

These parameter "abuses" certainly make particular uses more succinct,
but on the downside, they are more syntax to learn, as opposed to being
able to draw upon what one already knows about Ruby.

T.