From: Tsuyoshi Sawada <sawadatsuyoshi@...>
Date: 2011-11-03T17:58:19+09:00
Subject: [ruby-dev:44787] [ruby-trunk - Feature #5554] A method that applies self to a Proc if self is a Symbol


Issue #5554 has been updated by Tsuyoshi Sawada.


本当は、意図したのは、どのようなSymbolがあるか簡単には分からない場合、もしくは別のところで関連するメソッドが定義されていて、Symbolの一覧を複数の場所で更新しなければならなくなる場合で、例えば次のような場合です:

　　　　proc =>sym{some_method_chain.send(sym)}  # sym can be :foo, :bar, ..., which are defined elsewhere

でも、中田さんのおっしゃているのも分かります。
----------------------------------------
Feature #5554: A method that applies self to a Proc if self is a Symbol
http://redmine.ruby-lang.org/issues/5554

Author: Tsuyoshi Sawada
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 


Often, you want to apply a Proc to self if self is a Symbol, but not do anything if otherwise. In this case, something I call Object#desymbolize may be convenient:

    proc = ->sym{
        case sym
        when :small_icon  then "16pt"
        when :medium_icon then "32pt"
        when :large_icon  then "64pt"
        end
    }
    :small_icon.desymbolize(&proc) => "16pt"
    "18pt".desymbolize(&proc) => "18pt"

An implementation may be as follows:

class Object
	def desymbolize; self end
end
class Symbol
	def desymbolize &pr; pr.call(self) end
end



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