From: Nick Howard <ndh@...>
Date: 2011-07-20T02:58:19+09:00
Subject: [ruby-core:38203] [Ruby 1.9 - Feature #5054] Compress a sequence of ends


Issue #5054 has been updated by Nick Howard.


I don't think this is a good idea because I think it makes code harder to modify correctly.

Say you wanted to add a new method to MyModule::MyClass. With the old syntax it's simple, just add a line below the method defined in the class body.

module MyModule
  class MyClass
    def my_method
      10.times do
        if rand < 0.5 
          p :small
        end 
      end 
    end

    def your_method
      p :something
    end 
  end 
end

with en+d, you now need to count the number of 'n's in the last en+d,
count the number of expressions in the method that need to be closed,
create a new en+d with that number,
and put the remainder at the end. 
Then, write your method and add more 'n's to the final end to match up with the number of blocks you opened.

module MyModule
  class MyClass
    def my_method
      10.times do
        if rand < 0.5 
          p :small
    ennnd

    def your_method
      p :something
ennnd
----------------------------------------
Feature #5054: Compress a sequence of ends
http://redmine.ruby-lang.org/issues/5054

Author: ANDO Yasushi ANDO
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 


Though as matz said at rubykaigi2011 ruby is a quite good language, many people hate a long sequence of `end' like this:

module MyModule
  class MyClass
    def my_method
      10.times do
        if rand < 0.5 
          p :small
        end 
      end 
    end 
  end 
end

So, I'd like to propose introducing a special keyword, en(n+)d. Using this keyword, we can rewrite the above example like this:

module MyModule
  class MyClass
    def my_method
      10.times do
        if rand < 0.5 
          p :small
        ennnnnd 

I know matz's already rejected a python-style block. He wrote:

> it works badly with
>   * tab/space mixture
>   * templates, e.g. eRuby
>   * expression with code chunk, e.g lambdas and blocks
http://www.ruby-forum.com/topic/108457

These bad things won't occur by introducing en(n+)d.

Some implementations already exists.

JRuby
- https://gist.github.com/1088363

CRuby
- http://www.atdot.net/sp/raw/kn9iol
- http://d.hatena.ne.jp/ku-ma-me/20110718/p1

Thanks for your consideration.


-- 
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