I'm trying to add a continuation mark inside a function, but I want
that the new mark to be visible after the functions returns. (Mostly
for curiosity, not an actual problem.)
I want something like this:
;--
#lang racket/base
(define (display-cm-x)
(displayln
(continuation-mark-set->list
(current-continuation-marks) 'x)))
(define (add-cm-x v)
'???)
(define-syntax-rule (with-cm-x v body ...)
(with-continuation-mark 'x v
body ...))
(let ()
(display-cm-x) ;==>()
(with-cm-x 7
(display-cm-x)) ;==>(7)
(display-cm-x) ;==>()
(add-cm-x 7)
(display-cm-x) ;actual==>(), expected==>(7)
)
;--
The last line prints (), but I wish it prints (7).
Gustavo
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