racket/collects/scheme/private/define-struct.ss
Matthew Flatt d194a8b145 doc serialize
svn: r7875
2007-11-30 21:34:16 +00:00

460 lines
21 KiB
Scheme

;; Based on
;; (planet "struct.ss" ("ryanc" "macros.plt" 1 0)))
(module define-struct '#%kernel
(#%require "more-scheme.ss" "small-scheme.ss" "define.ss" "../stxparam.ss"
(for-syntax '#%kernel "define.ss"
"stx.ss" "stxcase-scheme.ss" "small-scheme.ss"
"stxloc.ss" "qqstx.ss"
"struct-info.ss"))
(#%provide define-struct*
define-struct/derived
struct-field-index)
(define-syntax-parameter struct-field-index
(lambda (stx)
(raise-syntax-error #f "allowed only within a structure type definition" stx)))
(define (check-struct-type name what)
(when what
(unless (struct-type? what)
(raise-type-error name "struct-type or #f" what)))
what)
(define (check-inspector name what)
(when what
(unless (inspector? what)
(raise-type-error name "inspector or #f" what)))
what)
(define-syntax (define-struct* stx)
(syntax-case stx ()
[(_ . rest)
(with-syntax ([stx stx])
#'(define-struct/derived stx . rest))]))
(define-syntax (define-struct/derived full-stx)
(define make-field list)
(define field-id car)
(define field-default-value cadr)
(define field-auto? caddr)
(define field-mutable? cadddr)
(define (build-name id . parts)
(datum->syntax
id
(string->symbol
(apply string-append
(map (lambda (p)
(if (syntax? p)
(symbol->string (syntax-e p))
p))
parts)))
id))
(define (bad why kw where . alt)
(raise-syntax-error
#f
(format "~a ~a specification~a"
why
(if (string? kw)
kw
(syntax-e kw))
where)
stx
(if (null? alt) kw (car alt))))
(define (check-exprs orig-n ps)
(let loop ([nps (cdr ps)][n orig-n])
(unless (zero? n)
(unless (and (pair? nps)
(not (keyword? (syntax-e (car nps)))))
(raise-syntax-error
#f
(format "expected ~a expression~a after keyword~a"
orig-n
(if (= orig-n 1) "" "s")
(if (pair? nps)
", found a keyword"
""))
stx
(car ps)))
(loop (cdr nps) (sub1 n)))))
;; Parse one field with a sequence of keyword-based specs:
(define (parse-field f)
(syntax-case f ()
[id
(identifier? #'id)
(make-field #'id #f #f #f)]
[(id p ...)
(identifier? #'id)
(let loop ([ps (syntax->list #'(p ...))]
[def-val #f]
[auto? #f]
[mutable? #f])
(cond
[(null? ps) (make-field #'id def-val auto? mutable?)]
[(eq? '#:mutable (syntax-e (car ps)))
(when mutable?
(bad "redundant" (car ps) " for field"))
(loop (cdr ps) def-val auto? #t)]
#;
[(eq? #:default (syntax-e (car ps)))
(check-exprs 1 ps)
(when def-val
(bad "multiple" (car ps) " for field"))
(loop (cddr ps) (cadr ps) auto? mutable?)]
[(eq? '#:auto (syntax-e (car ps)))
(when auto?
(bad "redundant" (car ps) " for field"))
(loop (cdr ps) def-val #t mutable?)]
[else
(raise-syntax-error
#f
(if (keyword? (syntax-e (car ps)))
"unrecognized field-specification keyword"
"expected a field-specification keyword")
stx
(car ps))]))]
[_else
(raise-syntax-error
#f
"expected a field identifier or a parenthesized identifier and field-specification sequence"
stx
f)]))
(define (lookup config s)
(cdr (assq s config)))
(define (extend-config config s val)
(cond
[(null? config) (error 'struct "internal error: can't find config element: ~s" s)]
[(eq? (caar config) s) (cons (cons s val) (cdr config))]
[else (cons (car config) (extend-config (cdr config) s val))]))
;; Parse sequence of keyword-based struct specs
(define (parse-props p super-id)
(let loop ([p p]
[config '((#:super . #f)
(#:inspector . #f)
(#:auto-value . #f)
(#:props . ())
(#:mutable . #f)
(#:guard . #f)
(#:omit-define-values . #f)
(#:omit-define-syntaxes . #f))])
(cond
[(null? p) config]
[(eq? '#:super (syntax-e (car p)))
(check-exprs 1 p)
(when (lookup config '#:super)
(bad "multiple" (car p) "s"))
(when super-id
(raise-syntax-error
#f
(string-append
"#:super specification disallowed because a struct supertype id"
" was supplied with the struct type id")
stx
(car p)))
(loop (cddr p)
(extend-config config '#:super (cadr p)))]
[(memq (syntax-e (car p))
'(#:guard #:auto-value))
(let ([key (syntax-e (car p))])
(check-exprs 1 p)
(when (lookup config key)
(bad "multiple" (car p) "s"))
(loop (cddr p)
(extend-config config key (cadr p))))]
[(eq? '#:property (syntax-e (car p)))
(check-exprs 2 p)
(loop (cdddr p)
(extend-config config
'#:props
(cons (cons (cadr p) (caddr p))
(lookup config '#:props))))]
[(eq? '#:inspector (syntax-e (car p)))
(check-exprs 1 p)
(when (lookup config '#:inspector)
(bad "multiple" "#:inspector or #:transparent" "s" (car p)))
(loop (cddr p)
(extend-config config '#:inspector (cadr p)))]
[(eq? '#:transparent (syntax-e (car p)))
(when (lookup config '#:inspector)
(bad "multiple" "#:inspector or #:transparent" "s" (car p)))
(loop (cdr p)
(extend-config config '#:inspector #'#f))]
[(memq (syntax-e (car p))
'(#:mutable #:omit-define-values #:omit-define-syntaxes))
(let ([key (syntax-e (car p))])
(when (lookup config key)
(bad "redundant" (car p) ""))
(loop (cdr p)
(extend-config config key #t)))]
[else
(raise-syntax-error
#f
(if (keyword? (syntax-e (car p)))
"unrecognized struct-specification keyword"
"expected a struct-spefication keyword")
stx
(car p))])))
(define stx (syntax-case full-stx ()
[(_ stx . _) #'stx]))
(syntax-case full-stx ()
[(_ (fm . _) id (field ...) prop ...)
(let-values ([(id super-id)
(if (identifier? #'id)
(values #'id #f)
(syntax-case #'id ()
[(id super-id)
(and (identifier? #'id)
(identifier? #'super-id))
(values #'id #'super-id)]
[else
(raise-syntax-error
#f
"bad syntax; expected <id> for structure-type name or (<id> <id>) for name and supertype name"
stx
#'id)]))])
(let ([super-info
(and super-id
(let ([v (syntax-local-value super-id (lambda () #f))])
(if (struct-info? v)
(extract-struct-info v)
(raise-syntax-error
#f
(format "parent struct type not defined~a"
(if v
(format " (~a does not name struct type information)"
(syntax-e super-id))
""))
stx
super-id))))])
(when (and super-info
(not (car super-info)))
(raise-syntax-error
#f
"no structure type descriptor available for supertype"
stx
super-id))
(let* ([field-stxes (syntax->list #'(field ...))]
[fields (map parse-field field-stxes)]
[dup (check-duplicate-identifier (map field-id fields))])
(when dup
(raise-syntax-error
#f
"duplicate field identifier"
stx
dup))
(let ([auto-count
(let loop ([fields fields] [field-stxes field-stxes] [auto? #f])
(cond
[(null? fields) 0]
[(field-auto? (car fields))
(+ 1 (loop (cdr fields) (cdr field-stxes) #t))]
[auto?
(raise-syntax-error
#f
"non-auto field after an auto field disallowed"
stx
(car field-stxes))]
[else
(loop (cdr fields) (cdr field-stxes) #f)]))])
(let-values ([(inspector super-expr props auto-val guard mutable?
omit-define-values? omit-define-syntaxes?)
(let ([config (parse-props (syntax->list #'(prop ...)) super-id)])
(values (lookup config '#:inspector)
(lookup config '#:super)
(lookup config '#:props)
(lookup config '#:auto-value)
(lookup config '#:guard)
(lookup config '#:mutable)
(lookup config '#:omit-define-values)
(lookup config '#:omit-define-syntaxes)))])
(when mutable?
(for-each (lambda (f f-stx)
(when (field-mutable? f)
(raise-syntax-error
#f
"redundant #:mutable specification in field"
stx
f-stx)))
fields field-stxes))
(let ([struct: (build-name id "struct:" id)]
[make- (build-name id "make-" id)]
[? (build-name id id "?")]
[sels (map (lambda (f)
(build-name id ; (field-id f)
id "-" (field-id f)))
fields)]
[sets (let loop ([fields fields])
(cond
[(null? fields) null]
[(not (or mutable? (field-mutable? (car fields))))
(loop (cdr fields))]
[else
(cons (build-name id ; (field-id (car fields))
"set-"
id
"-"
(field-id (car fields))
"!")
(loop (cdr fields)))]))]
[super-struct: (if super-info
(or (car super-info)
(raise-syntax-error
#f
"no structure type descriptor available for supertype"
stx
super-id))
(and super-expr
#`(check-struct-type 'fm #,super-expr)))])
(let ([run-time-defns
(lambda ()
(quasisyntax/loc stx
(define-values (#,struct: #,make- #,? #,@sels #,@sets)
(let-values ([(struct: make- ? -ref -set!)
(syntax-parameterize ([struct-field-index
(lambda (stx)
(syntax-case stx #,(map field-id fields)
#,@(let loop ([fields fields][pos 0])
(cond
[(null? fields) null]
[else (cons #`[(_ #,(field-id (car fields))) #'#,pos]
(loop (cdr fields) (add1 pos)))]))
[(_ name) (raise-syntax-error #f "no such field" stx #'name)]))])
(make-struct-type '#,id
#,super-struct:
#,(- (length fields) auto-count)
#,auto-count
#,auto-val
#,(if (null? props)
#'null
#`(list #,@(map (lambda (p)
#`(cons #,(car p) #,(cdr p)))
props)))
#,(if inspector
#`(check-inspector 'fm #,inspector)
#`(current-inspector))
#f
'#,(let loop ([i 0]
[fields fields])
(cond
[(null? fields) null]
[(field-auto? (car fields)) null]
[(not (or mutable? (field-mutable? (car fields))))
(cons i (loop (add1 i) (cdr fields)))]
[else (loop (add1 i) (cdr fields))]))
#,guard))])
(values struct: make- ?
#,@(let loop ([i 0][fields fields])
(if (null? fields)
null
(cons #`(make-struct-field-accessor -ref #,i '#,(field-id (car fields)))
(loop (add1 i) (cdr fields)))))
#,@(let loop ([i 0][fields fields])
(if (null? fields)
null
(if (not (or mutable? (field-mutable? (car fields))))
(loop (add1 i) (cdr fields))
(cons #`(make-struct-field-mutator -set! #,i '#,(field-id (car fields)))
(loop (add1 i) (cdr fields)))))))))))]
[compile-time-defns
(lambda ()
(let ([protect (lambda (sel)
(and sel
(if (syntax-e sel)
#`(c (quote-syntax #,sel))
sel)))])
(quasisyntax/loc stx
(define-syntaxes (#,id)
(let ([c (syntax-local-certifier)])
(make-struct-info
(lambda ()
(list
(c (quote-syntax #,struct:))
(c (quote-syntax #,make-))
(c (quote-syntax #,?))
(list
#,@(map protect (reverse sels))
#,@(if super-info
(map protect (list-ref super-info 3))
(if super-expr
'(#f)
null)))
(list
#,@(reverse
(let loop ([fields fields][sets sets])
(cond
[(null? fields) null]
[(not (or mutable? (field-mutable? (car fields))))
(cons #f (loop (cdr fields) sets))]
[else
(cons (protect (car sets))
(loop (cdr fields) (cdr sets)))])))
#,@(if super-info
(map protect (list-ref super-info 4))
(if super-expr
'(#f)
null)))
#,(if super-id
(protect super-id)
(if super-expr
#f
#t))))))))))])
(let ([result
(cond
[(and (not omit-define-values?) (not omit-define-syntaxes?))
#`(begin #,(run-time-defns) #,(compile-time-defns))]
[omit-define-syntaxes?
(run-time-defns)]
[omit-define-values?
(compile-time-defns)]
[else #'(begin)])])
(if super-id
(syntax-property result
'disappeared-use
(syntax-local-introduce super-id))
result)))))))))]
[(_ _ id . _)
(not (or (identifier? #'id)
(and (syntax->list #'id)
(= 2 (length (syntax->list #'id)))
(andmap identifier? (syntax->list #'id)))))
(raise-syntax-error
#f
"bad syntax; expected <id> for structure-type name or (<id> <id>) for name and supertype name"
stx
#'id)]
[(_ _ id (field ...) . _)
(begin
(for-each parse-field (syntax->list #'(field ...)))
(raise-syntax-error
#f
"bad syntax after field sequence"
stx))]
[(_ _ id fields . _)
(raise-syntax-error
#f
"bad syntax; expected a parenthesized sequence of field descriptions"
stx
#'fields)]
[(_ _ id)
(raise-syntax-error
#f
"bad syntax; missing fields"
stx)]
[_
(raise-syntax-error
#f
"bad syntax"
stx)])))