From: katz bo <redmine@...>
Date: 2009-12-22T01:02:33+09:00
Subject: [ruby-core:27271] [Bug #2422] splat operator fails on array of 1 element

Issue #2422 has been updated by katz bo.


Thank you, Benoit Daloze.

I wrote:
> What does Ruby do with a = *[] ? Let me illustrate an IMO proper way:
> Ruby looks at *[] and goes, "Fine, let me unpack it."
> Ruby unpacks *[].
> Then Ruby goes, "Nothing? But I can't _carry_ <nothing>! No.. not in an
> assignment! Wait.. Let's do it!"
> Ruby marks it as nil.

As now I think I understand assignment better, I'd like to correct myself a bit:

foo = *[]
When processing the above line, the Ruby interpreter does these things:
1) First Ruby sees the left side of the assignment, i.e. foo =, and he points foo to nil.
2) Then Ruby tries to evaluate the rvalue. Looking at the *, Ruby unpacks the array [].
3) Ruby gets a little surprised when he finds it's empty in there.
4) So Ruby (happily) does nothing, because there is nothing to re-point foo to.

That's the story. And this story tells me foo ends up nil.
What's the new story about ruby 1.9 if it's not a bug?
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