From: matz@... (Yukihiro Matsumoto)
Date: 2003-02-04T09:11:32+09:00
Subject: Re: Local variables & blocks

Hi,

In message "Re: Local variables & blocks"
    on 03/02/04, ichimal@fenix.ne.jp <ichimal@fenix.ne.jp> writes:

|  What's #<undef> in R5RS?
|  Is it virtual unspecific value such that "result of (if #f #f)" in
|the definition of "do" in the section derived expression types?

Yes.

|Points are below:
|    (*) first-class object,
|    (*) not as false, at least,
|    (*) to check equivalency is supported;
|        (**) ==, != and nonInit? methods may be defined.

But why this is needed in addition to false and nil?  That's my point.
Scheme has #f and #<unspecified>, Ruby has false and nil.
What's wrong with that?  nil being "false value"?

|>|  Maybe, I have over reactioned to the words "reasonable" and
|>|"save additional test". Usually, I cannot belive those words.
|>
|>whose words are they?
|
|  Not yours. These are Mr.Klemme's. You did just affirm it.

Did I?

							matz.