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let/ec swapped out in update

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This commit is contained in:
Andrew Kent 2015-01-17 14:20:30 +05:30
parent 9a39c3e793
commit 7633d6d1b8
1 changed files with 9 additions and 10 deletions
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19
typed-racket-lib/typed-racket/typecheck/tc-envops.rkt
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@ -46,16 +46,15 @@
;; a polymorphic field. Because subtyping is nominal and accessor
;; functions do not reflect this, this behavior is unobservable
;; except when an a variable aliases the field in a let binding
(let/ec abort
(make-Struct nm par
(list-update flds idx (match-lambda
[(fld: e acc-id #f)
(let ([ft* (update e ft pos? rst)])
(if (Bottom? ft*)
(abort ft*)
(make-fld ft* acc-id #f)))]
[_ (int-err "update on mutable struct field")]))
proc poly pred))]
(let*-values ([(lhs rhs) (split-at flds idx)]
[(ty* acc-id) (match rhs
[(cons (fld: ty acc-id #f) _)
(values (update ty ft pos? rst) acc-id)]
[_ (int-err "update on mutable struct field")])])
(cond
[(Bottom? ty*) ty*]
[else (let ([flds* (append lhs (cons (make-fld ty* acc-id #f) (cdr rhs)))])
(make-Struct nm par flds* proc poly pred))]))]]
;; otherwise
[(t '())