From ruby-core  Wed Apr 07 13:08:29 2010
From: Ken Bloom <kbloom () gmail ! com>
Date: Wed, 07 Apr 2010 13:08:29 +0000
To: ruby-core
Subject: [ruby-core:29299] Re: Proposal: Module#thunk_method
Message-Id: <pan.2010.04.07.04.55.13 () gmail ! com>
X-MARC-Message: https://marc.info/?l=ruby-core&m=127064581421771

On Tue, 06 Apr 2010 09:42:30 +0900, Charles Oliver Nutter wrote:

> Many people use define_method solely so they can define a new method
> that just returns a value, such as for memoization. Unfortunately
> define_method is a full block dispatch, and as a result it can be a lot
> slower than regular method calls.
> 
> I propose a new method Module#thunk_method which defines a
> fast-as-possible method that just returns the value you give it:
> 
> class Foo
>   thunk_method :value, "some value"
> end
> 
> Foo.new.value # => "some value"
> 
> This would eliminate define_method cases like this:
> 
> # lazy-memozing value method
> def value
>   a = some_expensive_calculation
>   self.class.class_eval {define_method(:value) {a}}
> end
> 
> Thoughts? Should this go into RedMine?
> 
> - Charlie

If this optimization is worthwhile, then shouldn't the Ruby interpreter 
do some sort of static analysis on the closure and the local variable to 
identify this case and give you the performance boost while still using 
the define_method API?

-- 
Chanoch (Ken) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/