BACKGROUND:
Per the documentation:
with-continuation-mark causes a key to be associated with a binding
within a continuation frame
continuation-mark-set->list returns the binding(s) associated with that
particular key, for any given continuation-mark-set
while
continuation-mark-set-first returns the first (innermost) binding
associated with a particular key
QUESTIONABLE BEHAVIOR
The issue is:
if a key is reused, the only binding continuation-mark-set->list returns
is the innermost binding.
So continuation-mark-set->list could only possibly return **one** value
and
continuation-mark-set-first appears redundant
Is that the desired behavior? I would have expected
continuation-mark-set->list to return all the bindings for a particular
key.
Additionally, I suspect continuation-mark-set->context has to be
implemented using the 'return a list of all bindings for a single key'
behavior, since the documentation indicates it uses a single private
key.
EXAMPLE
#lang racket
(with-continuation-mark 'global 'outermost-value
(let/cc k-outer
(with-continuation-mark 'global 'middle-value
(let/cc k-inner
(with-continuation-mark 'global 'inner-value (begin
(display
(continuation-mark-set->list (current-continuation-marks) 'global))
(newline)
(display
(continuation-mark-set->list (continuation-marks k-inner) 'global))
(newline)
(display
(continuation-mark-set->list (continuation-marks k-outer) 'global))
))))))
;Returns
;(inner-value)
;(middle-value)
;(outermost-value)
but I would have expected:
;Returns
;(inner-value) (middle-value) (outermost-value)
;(middle-value) (outermost-value)
;(outermost-value)
Thanks very much for looking at this.
R/
Zack
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