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cs: allow unsafe-undefined in variables

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Distinguish "not initialized" from "value is unsafe-undefined".
Otherwise, `(dynamic-require 'racket/unsafe/undefined 'unsafe-undefined)`
 fails.
This commit is contained in:
Matthew Flatt 2019-01-01 13:27:05 -07:00
parent dbabafa147
commit b9e1d23f0d
1 changed files with 16 additions and 12 deletions
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28
racket/src/cs/linklet.sls
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@ -599,8 +599,12 @@
constance ; #f (mutable), 'constant, or 'consistent (always the same shape)
inst-box)) ; weak pair with instance in `car`
;; Can't use `unsafe-undefined`, because the expander expects to be
;; able to store `unsafe-undefined` in variables
(define variable-undefined (gensym 'undefined))
(define (make-internal-variable name)
(make-variable unsafe-undefined name #f (cons #!bwp #f)))
(make-variable variable-undefined name #f (cons #!bwp #f)))
(define (do-variable-set! var val constance as-define?)
(cond
@ -633,13 +637,13 @@
(do-variable-set! var val constance #f))
(define (variable-set!/check-undefined var val constance)
(when (eq? (variable-val var) unsafe-undefined)
(when (eq? (variable-val var) variable-undefined)
(raise-undefined var #t))
(variable-set! var val constance))
(define (variable-ref var)
(let ([v (variable-val var)])
(if (eq? v unsafe-undefined)
(if (eq? v variable-undefined)
(raise-undefined var #f)
v)))
@ -654,7 +658,7 @@
(map (lambda (sym import-abi)
(let ([var (or (hash-ref ht sym #f)
(raise-linking-failure "is not exported" target-inst inst sym))])
(when (eq? (variable-val var) unsafe-undefined)
(when (eq? (variable-val var) variable-undefined)
(raise-linking-failure "is uninitialized" target-inst inst sym))
(if import-abi
(variable-val var)
@ -704,7 +708,7 @@
[inst-box (weak-cons inst #f)])
(map (lambda (sym)
(or (hash-ref ht sym #f)
(let ([var (make-variable unsafe-undefined sym #f inst-box)])
(let ([var (make-variable variable-undefined sym #f inst-box)])
(hash-set! ht sym var)
var)))
syms)))
@ -730,7 +734,7 @@
[else a-known-constant]))])))
(define (check-variable-set var sym)
(when (eq? (variable-val var) unsafe-undefined)
(when (eq? (variable-val var) variable-undefined)
(raise
(|#%app|
exn:fail:contract:variable
@ -786,11 +790,11 @@
(define instance-variable-value
(case-lambda
[(i sym fail-k)
(let* ([var (hash-ref (instance-hash i) sym unsafe-undefined)]
[v (if (eq? var unsafe-undefined)
unsafe-undefined
(let* ([var (hash-ref (instance-hash i) sym variable-undefined)]
[v (if (eq? var variable-undefined)
variable-undefined
(variable-val var))])
(if (eq? v unsafe-undefined)
(if (eq? v variable-undefined)
(fail-k)
v))]
[(i sym)
@ -812,7 +816,7 @@
(raise-argument-error 'instance-set-variable-value! "symbol?" i))
(check-constance 'instance-set-variable-value! mode)
(let ([var (or (hash-ref (instance-hash i) k #f)
(let ([var (make-variable unsafe-undefined k #f (weak-cons i #f))])
(let ([var (make-variable variable-undefined k #f (weak-cons i #f))])
(hash-set! (instance-hash i) k var)
var))])
(variable-set! var v mode))]))
@ -824,7 +828,7 @@
(raise-argument-error 'instance-unset-variable! "symbol?" i))
(let ([var (hash-ref (instance-hash i) k #f)])
(when var
(set-variable-val! var unsafe-undefined))))
(set-variable-val! var variable-undefined))))
(define (instance-describe-variable! i k desc)
(unless (instance? i)