From: matz@... (Yukihiro Matsumoto)
Date: 2002-06-13T01:30:10+09:00
Subject: Re: a new block parameter/variable notation (Re: ruby-dev summary 17252-17356)

Hi,

In message "Re: a new block parameter/variable notation (Re: ruby-dev summary 17252-17356)"
    on 02/06/13, Dave Thomas <Dave@PragmaticProgrammer.com> writes:

|> (i.e. lambda{|a|p a}.call(1,2,3) trap) at once.
|
|Is that the design flaw, or it is that
|
|   a = 1,2,3
|
|works?  It seems to me that the target (the lhs of an assignment or
|the block parameter list) should determine whether you're performing a
|parallel assignment. If that was the case, then your example above
|wouldn't be a problem: your example would be a runtime error (too many
|arguments) and mine would be a compile time error.

Things are not that simple.  Suppose we have:

  def foo(obj)
    obj.each do |x|
      p x
    end
  end

then

  foo([1,2,3])

is OK, but for

  foo({1=>2, 2=>4})

the following assignments are done internally: 

  x = 1, 2
  x = 2, 4

We can remove "a = 1,2,3" from the syntax, but we cannot remove it
from iterators.

							matz.