From: Ilias Lazaridis <ilias@...>
Date: 2011-06-05T14:55:28+09:00
Subject: Re: CORE - Altering Behaviour of "each do" (default param "item")

On 4 Éïýí, 21:02, Robert Klemme <shortcut...@googlemail.com> wrote:
> On 04.06.2011 16:19, Michael Sokol wrote:
>
> > Actually it would be possible, although very ugly.
>
> > You need to evaluate in the context of the current instance
> > (instance_eval) - not yield - the block you pass to the each method
> > of your object (an array in this case).
>
> > Then you can define a print method that behaves like a coroutine
> > (check out ruby fibers) and returns each element of your array.
>
> There is another approach which does not suffer from the side effect of
> changing self which can be disastrous: create a thread local which holds
> a stack of values and make item peek at the top element of it:
>
> class Object
>    def new_each
>      stack = (Thread.current[:__item__] ||= [])

what does "(Thread.current[:__item__] ||= [])" do?

>      each do |x|
>        stack.push x
[...]

> This approach
> - does not change 'self'
> - is thread safe
> - is nesting safe

This sounds good.

But you suggestion adds Class#new_each.

The goal was, to alter the existent behaviour of Array#each.

I've tried to modify your code to achieve this, but I failed.

.

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