Wataru Nakanishi scripsit:

> In 4.2.5. Delayed evaluation, p.19, it's written
> > (make-promise obj)        lazy library procedure

That's correct.

> but in 7.3. Derived expression types, p.71,
> > (make-promise #f (lambda () <expression>))
> and
> > (define make-promise > (lambda (done? proc) > (list (cons done? proc))))
>
> Which definition is true?

You'll note that the implementation in 7.3 doesn't claim to be an
implementation of `make-promise`.  It was written before `make-promise`
was added to the standard, and happens to use the same name.

Hopefully someone will provide a more comprehensive implementation of
the lazy library that can be dropped into 7.3.

--
John Cowan          http://www.ccil.org/~cowan        cowan@ccil.org
You let them out again, Old Man Willow!
What you be a-thinking of?  You should not be waking!
Eat earth!  Dig deep!  Drink water!  Go to sleep!
Bombadil is talking.

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