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Re: Multiple values in Dylan
- To: Scott_Fahlman@SEF-PMAX.SLISP.CS.CMU.EDU
- Subject: Re: Multiple values in Dylan
- From: John D. Ramsdell <firstname.lastname@example.org>
- Date: Fri, 06 Nov 92 13:44:54 EST
- Cc: email@example.com, info-dylan@CAMBRIDGE.APPLE.COM
- In-reply-to: Your message of "Fri, 06 Nov 92 12:47:35 EST." <9211061752.AA04918@brazil.cambridge.apple.com>
- Posted-date: Fri, 06 Nov 92 13:44:54 EST
> Scott, could you give some examples?
> (cons (foo a) (bar b) (bletch c))
> It kind of looks like too many arguments are being passed there, and my
> sophisticated syntax-checking editor just complained. But in this case
> it's OK, since bar really does some side-effect and returns zero values, so
> it acts sort of like a comment -- drop it in code anywhere. BAR isn't
> written yet, so none of the programming tools know that it's going to be
As I understand it, this example would not be okay in Jim's version of
multiple values in Dylan. Bar is being called in a position that
expects one value, but the bar you describe is returning no values. A
continuation passing version of the expression follows. Clearly, cons
is being called with too many arguments.
(lambda (foo-a) ; Foo's continuation
(lambda (bar-b) : Bar's contination
(lambda (bletch-c) ; Bletch's continuation
You must call bar from an expression that expects exactly zero
values or from an expression that accepts any number of return values.
Try begin as in:
(begin (bar b) #t)
> (+ (foo a) (bar b) (bletch c))
This example is also in error for the same reason as the previous one.