Implement field/c using a struct rather than make-contract
Asumu suggested that using a struct with the contract property is generally preferred.
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@ -112,27 +112,38 @@
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[() (wrap (field))]
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[(x) (field (guard x))]))
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(define (field/c ctc)
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(let ([ctc (coerce-contract 'field/c ctc)])
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(make-contract #:name (build-compound-type-name 'field/c ctc)
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#:first-order
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(lambda (f) (and (field-handle? f)
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(ctc (f))))
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#:late-neg-projection
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(lambda (blame)
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(define proc (get/build-late-neg-projection ctc))
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(define blame/c (blame-add-context blame "the field of"))
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(define proj (proc (blame-swap blame/c)))
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(define proj-pos (lambda (x) (proj x (blame-positive blame))))
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(lambda (f neg-party)
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(define proj-neg (lambda (x) (proj x neg-party)))
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(cond
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[(field-handle? f)
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(make-field-proxy f proj-neg proj-pos)]
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[else (raise-blame-error blame/c
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#:missing-party neg-party
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f
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'(expected: "a field"))]))))))
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(define/subexpression-pos-prop (field/c ctc)
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(make-field/c (coerce-contract 'field/c ctc)))
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(define-struct field/c (ctc)
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#:property prop:custom-write custom-write-property-proc
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#:omit-define-syntaxes
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#:property prop:contract
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(build-contract-property
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#:name
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(lambda (ctc) (build-compound-type-name 'field/c (field/c-ctc ctc)))
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#:first-order
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(lambda (ctc)
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(let ([ctc (field/c-ctc ctc)])
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(lambda (f) (and (field-handle? f)
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(ctc (f))))))
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#:late-neg-projection
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(lambda (ctc)
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(let ([ctc (field/c-ctc ctc)])
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(lambda (blame)
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(define proc (get/build-late-neg-projection ctc))
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(define blame/c (blame-add-context blame "the field of"))
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(define proj (proc (blame-swap blame/c)))
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(define proj-pos (lambda (x) (proj x (blame-positive blame))))
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(lambda (f neg-party)
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(define proj-neg (lambda (x) (proj x neg-party)))
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(cond
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[(field-handle? f)
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(make-field-proxy f proj-neg proj-pos)]
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[else (raise-blame-error blame/c
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#:missing-party neg-party
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f
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'(expected: "a field"))])))))))
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(struct actor-state (mux ;; Mux
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facets ;; (Hash FID Facet)
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