25 lines
614 B
Scheme
25 lines
614 B
Scheme
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;;; weak table with weak values
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(define-record-type weak-table
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(really-make-weak-table table)
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weak-table?
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(table weak-table-table))
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(define (make-value-weak-table)
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(really-make-weak-table (make-integer-table)))
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(define (add-to-weak-table! table address object)
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(table-set! (weak-table-table table)
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address
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(make-weak-pointer object)))
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(define (remove-from-weak-table! table address)
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(table-set! (weak-table-table table)
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address #f))
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(define (lookup-in-weak-table table address)
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(cond
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((table-ref (weak-table-table table) address)
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=> weak-pointer-ref)
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(else #f)))
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