From: "David A. Black" <dblack@...>
Date: 2008-04-30T23:07:09+09:00
Subject: Re: How to create "def method(item)= (value)" ?

Hi --

On Wed, 30 Apr 2008, Phillip Gawlowski wrote:

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> David A. Black wrote:
>
> |>
> |> Sort of. As a singleton method, you get the syntax error. But not if you
> |> define [] as a method:
> |>
> |> irb(main):001:0> def []=(key,value)
> |> irb(main):002:1> end
> |> => nil
> |
> | It's not the singletonness that stops it; you can do this:
> |
> |   def object.[]=(k,v) # etc.
> |
> | What made my example wrong was that I had concocted an illegal method
> | name.
>
> Though, it should (might?) be possible to implemetn something like
> Hash's or Array's
>
> hash[key]
> array[index]
>
> index methods for plain old object instances, too.

Sure:

   def object.[](index)
     # derive value you want here
   end

And then:

   object[something]

You always get the [] syntactic sugar for free when you define [].


David

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