Jörg F. Wittenberger scripsit:
> To sum up: the approach feels not very clean to me. It would be much
> more practical to add another argument to make-parameter and have it
> support all three parameter designs, wouldn't it?
It's actually easy to get thread-global parameters without any modifications
to Chicken using this procedure:
(define (make-global-parameter default)
(let ((value default))
(lambda maybe (if (null? maybe) value (set! value (car maybe))))))
What is returned looks like a parameter, quacks like a parameter,
and can be controlled with parameterize:
#;> (define p (make-global-parameter 32))
#;> (p)
32
#;> (p 33)
#;> (p)
33
#;> (parameterize ((p 45)) (p))
45
#;> (p)
33
#;> (parameterize ((p 45)) (error (p))
Error: 45
#;> (p)
33
--
Values of beeta will give rise to dom! John Cowan
(5th/6th edition 'mv' said this if you tried http://www.ccil.org/~cowan
to rename '.' or '..' entries; see [EMAIL PROTECTED]
http://cm.bell-labs.com/cm/cs/who/dmr/odd.html)
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