From: matz@... (Yukihiro Matsumoto)
Date: 2003-04-29T11:20:56+09:00
Subject: Re: block.call vs. yield

Hi,

In message "Re: block.call vs. yield"
    on 03/04/29, Brian Candler <B.Candler@pobox.com> writes:

|I imagine 'yield semantics' were put in the language to solve some problem,
|or make it work better in some circumstances; do you have an example of
|that?

'yield semantics' is assignment between block parameters and yield
arguments, so that

  |a| given 1 argument x works as a = x
  |a| given 2 arguments x, y works as a = x, y

That's because block parameters are originally loop variables.

|Suppose block parameters worked like function arguments - how would life be
|worse? (ignoring backwards compatibility)

I don't know (yet).  The whole behavior of yield and block parameters
is designed for assignment model.  At least I need to reconstruct my
mental model using function argument model.

							matz.