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records: Replace 'eval-when' with a proper 'define-syntax'.
* guix/records.scm (make-syntactic-constructor): Remove enclosing 'eval-when'. Turn into a 'syntax-rules' macro.
This commit is contained in:
Ludovic Courtès
parent
b45ce07a8a
commit
39fc041a7d
1 changed files with 92 additions and 96 deletions
188
guix/records.scm
188
guix/records.scm
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@ -42,106 +42,102 @@ (define-syntax record-error
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(format #f fmt args ...)
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form))))
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(eval-when (expand load eval)
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;; This procedure is a syntactic helper used by 'define-record-type*', hence
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;; 'eval-when'.
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(define-syntax make-syntactic-constructor
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(syntax-rules ()
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"Make the syntactic constructor NAME for TYPE, that calls CTOR, and
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expects all of EXPECTED fields to be initialized. DEFAULTS is the list of
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FIELD/DEFAULT-VALUE tuples, THUNKED is the list of identifiers of thunked
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fields, and DELAYED is the list of identifiers of delayed fields."
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((_ type name ctor (expected ...)
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#:thunked thunked
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#:delayed delayed
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#:defaults defaults)
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(define-syntax name
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(lambda (s)
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(define (record-inheritance orig-record field+value)
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;; Produce code that returns a record identical to ORIG-RECORD,
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;; except that values for the FIELD+VALUE alist prevail.
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(define (field-inherited-value f)
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(and=> (find (lambda (x)
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(eq? f (car (syntax->datum x))))
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field+value)
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car))
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(define* (make-syntactic-constructor type name ctor fields
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#:key (thunked '()) (defaults '())
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(delayed '()))
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"Make the syntactic constructor NAME for TYPE, that calls CTOR, and expects
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all of FIELDS to be initialized. DEFAULTS is the list of FIELD/DEFAULT-VALUE
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tuples, THUNKED is the list of identifiers of thunked fields, and DELAYED is
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the list of identifiers of delayed fields."
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(with-syntax ((type type)
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(name name)
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(ctor ctor)
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(expected fields)
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(defaults defaults))
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#`(define-syntax name
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(lambda (s)
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(define (record-inheritance orig-record field+value)
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;; Produce code that returns a record identical to ORIG-RECORD,
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;; except that values for the FIELD+VALUE alist prevail.
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(define (field-inherited-value f)
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(and=> (find (lambda (x)
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(eq? f (car (syntax->datum x))))
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field+value)
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car))
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;; Make sure there are no unknown field names.
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(let* ((fields (map (compose car syntax->datum) field+value))
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(unexpected (lset-difference eq? fields '(expected ...))))
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(when (pair? unexpected)
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(record-error 'name s "extraneous field initializers ~a"
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unexpected)))
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;; Make sure there are no unknown field names.
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(let* ((fields (map (compose car syntax->datum) field+value))
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(unexpected (lset-difference eq? fields 'expected)))
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(when (pair? unexpected)
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(record-error 'name s "extraneous field initializers ~a"
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unexpected)))
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#`(make-struct type 0
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#,@(map (lambda (field index)
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(or (field-inherited-value field)
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#`(struct-ref #,orig-record
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#,index)))
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'(expected ...)
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(iota (length '(expected ...))))))
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#`(make-struct type 0
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#,@(map (lambda (field index)
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(or (field-inherited-value field)
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#`(struct-ref #,orig-record
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#,index)))
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'expected
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(iota (length 'expected)))))
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(define (thunked-field? f)
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(memq (syntax->datum f) 'thunked))
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(define (thunked-field? f)
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(memq (syntax->datum f) '#,thunked))
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(define (delayed-field? f)
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(memq (syntax->datum f) 'delayed))
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(define (delayed-field? f)
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(memq (syntax->datum f) '#,delayed))
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(define (wrap-field-value f value)
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(cond ((thunked-field? f)
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#`(lambda () #,value))
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((delayed-field? f)
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#`(delay #,value))
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(else value)))
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(define (wrap-field-value f value)
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(cond ((thunked-field? f)
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#`(lambda () #,value))
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((delayed-field? f)
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#`(delay #,value))
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(else value)))
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(define (field-bindings field+value)
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;; Return field to value bindings, for use in 'let*' below.
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(map (lambda (field+value)
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(syntax-case field+value ()
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((field value)
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#`(field
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#,(wrap-field-value #'field #'value)))))
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field+value))
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(define (field-bindings field+value)
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;; Return field to value bindings, for use in 'let*' below.
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(map (lambda (field+value)
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(syntax-case field+value ()
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((field value)
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#`(field
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#,(wrap-field-value #'field #'value)))))
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field+value))
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(syntax-case s (inherit expected ...)
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((_ (inherit orig-record) (field value) (... ...))
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#`(let* #,(field-bindings #'((field value) (... ...)))
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#,(record-inheritance #'orig-record
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#'((field value) (... ...)))))
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((_ (field value) (... ...))
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(let ((fields (map syntax->datum #'(field (... ...))))
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(dflt (map (match-lambda
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((f v)
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(list (syntax->datum f) v)))
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#'defaults)))
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(syntax-case s (inherit #,@fields)
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((_ (inherit orig-record) (field value) (... ...))
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#`(let* #,(field-bindings #'((field value) (... ...)))
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#,(record-inheritance #'orig-record
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#'((field value) (... ...)))))
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((_ (field value) (... ...))
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(let ((fields (map syntax->datum #'(field (... ...))))
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(dflt (map (match-lambda
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((f v)
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(list (syntax->datum f) v)))
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#'defaults)))
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(define (field-value f)
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(or (and=> (find (lambda (x)
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(eq? f (car (syntax->datum x))))
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#'((field value) (... ...)))
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car)
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(let ((value
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(car (assoc-ref dflt (syntax->datum f)))))
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(wrap-field-value f value))))
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(define (field-value f)
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(or (and=> (find (lambda (x)
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(eq? f (car (syntax->datum x))))
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#'((field value) (... ...)))
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car)
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(let ((value
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(car (assoc-ref dflt (syntax->datum f)))))
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(wrap-field-value f value))))
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(let ((fields (append fields (map car dflt))))
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(cond ((lset= eq? fields 'expected)
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#`(let* #,(field-bindings
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#'((field value) (... ...)))
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(ctor #,@(map field-value 'expected))))
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((pair? (lset-difference eq? fields 'expected))
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(record-error 'name s
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"extraneous field initializers ~a"
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(lset-difference eq? fields
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'expected)))
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(else
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(record-error 'name s
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"missing field initializers ~a"
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(lset-difference eq? 'expected
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fields)))))))))))))
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(let ((fields (append fields (map car dflt))))
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(cond ((lset= eq? fields '(expected ...))
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#`(let* #,(field-bindings
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#'((field value) (... ...)))
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(ctor #,@(map field-value '(expected ...)))))
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((pair? (lset-difference eq? fields
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'(expected ...)))
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(record-error 'name s
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"extraneous field initializers ~a"
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(lset-difference eq? fields
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'(expected ...))))
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(else
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(record-error 'name s
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"missing field initializers ~a"
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(lset-difference eq?
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'(expected ...)
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fields)))))))))))))
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(define-syntax define-record-type*
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(lambda (s)
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@ -279,11 +275,11 @@ (define-record-type type
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field-spec* ...)
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(begin thunked-field-accessor ...
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delayed-field-accessor ...)
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#,(make-syntactic-constructor #'type #'syntactic-ctor #'ctor
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#'(field ...)
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#:thunked thunked
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#:delayed delayed
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#:defaults defaults))))))))
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(make-syntactic-constructor type syntactic-ctor ctor
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(field ...)
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#:thunked #,thunked
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#:delayed #,delayed
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#:defaults #,defaults))))))))
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(define* (alist->record alist make keys
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#:optional (multiple-value-keys '()))
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