On Tuesday, October 13, 2015 at 11:40:12 PM UTC, Alexis King wrote:
> Have you taken a look at parameters?
Short answer: yes. Long answer: they're convenient thread-local globals, but
still feel like globals to me.
(define a (make-parameter 0))
(define (called-at-hopefully-regular-intervals)
(a (+ (a) 1))
(define (something-stupid)
(let ((b (a)))
(totally-innocuous-event-loop)
(+ 3 b b b)))
A local variable session doesn't require me to for the internal implementation,
write a bunch of abstraction-rich difficult-to-optimize inscrutable state code,
whereas with parameters I always have to (call) them just in case their value
just changed.
It's like parameters force the internal stuff to use the careful, externally
exposed interface to access their own internal data.
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