racket/collects/syntax/struct.ss
Matthew Flatt 0d4bc2cd9d 299.107
svn: r259
2005-06-28 17:01:03 +00:00

324 lines
9.7 KiB
Scheme

(module struct mzscheme
(require (lib "etc.ss")
"stx.ss")
(require-for-template mzscheme)
(provide parse-define-struct
build-struct-names
build-struct-generation
build-struct-expand-info
struct-declaration-info?
generate-struct-declaration)
;; parse-define-struct stx stx -> (values id id-or-#f list-of-id stx)
(define (parse-define-struct stx orig-stx)
(define (parse-at-id)
(syntax-case stx ()
[(_ id . rest)
(identifier? #'id)
(parse-at-fields #'id #f #'rest)]
[(_ (id super-id) . rest)
(and (identifier? #'id)
(identifier? #'super-id))
(parse-at-fields #'id #'super-id #'rest)]
[(_ bad . rest)
(raise-syntax-error
#f
"expected an identifer or parenthesized sequence of two identifiers"
orig-stx
#'bad)]))
(define (parse-at-fields id sup-id rest)
(syntax-case rest ()
[((field ...) . rest)
(let ([fields (syntax->list #'(field ...))])
(for-each (lambda (id)
(unless (identifier? id)
(raise-syntax-error
#f
"expected a field identifier"
orig-stx
id)))
fields)
(parse-at-inspector id sup-id fields #'rest))]
[(bad . rest)
(raise-syntax-error
#f
"expected a parenthesized sequence of field identifiers"
orig-stx
#'bad)]
[_
(raise-syntax-error
#f
(string-append "expected fields after " (if sup-id
"struct name and parent name"
"struct name"))
orig-stx)]))
(define (parse-at-inspector id sup-id fields rest)
(syntax-case rest ()
[()
(values id sup-id fields #'(current-inspector))]
[(inspector more . rest)
(not (stx-null? #'rest))
(raise-syntax-error
#f
"unexpected form after inspector"
orig-stx
#'more)]
[(inspector)
(values id sup-id fields #'inspector)]
[(inspector . rest)
(raise-syntax-error
#f
"unexpected form after inspector"
orig-stx
#'rest)]
[_
(raise-syntax-error
#f
"bad syntax"
orig-stx)]))
(parse-at-id))
;; build-struct-names : id (list-of id) bool bool -> (list-of id)
(define build-struct-names
(opt-lambda (name-stx fields omit-sel? omit-set? [srcloc-stx #f])
(let ([name (symbol->string (syntax-e name-stx))]
[fields (map symbol->string (map syntax-e fields))]
[+ string-append])
(map (lambda (s)
(datum->syntax-object name-stx (string->symbol s) srcloc-stx))
(append
(list
(+ "struct:" name)
(+ "make-" name)
(+ name "?"))
(let loop ([l fields])
(if (null? l)
null
(append
(if omit-sel?
null
(list (+ name "-" (car l))))
(if omit-set?
null
(list (+ "set-" name "-" (car l) "!")))
(loop (cdr l))))))))))
(define build-struct-generation
(opt-lambda (name-stx fields omit-sel? omit-set? [super-type #f] [prop-value-list null]
[immutable-positions null] [mk-rec-prop-list (lambda (struct: make- ? acc mut) null)])
(let ([names (build-struct-names name-stx fields omit-sel? omit-set?)])
(build-struct-generation* names name-stx fields omit-sel? omit-set? super-type prop-value-list
immutable-positions mk-rec-prop-list))))
(define build-struct-generation*
(opt-lambda (names name fields omit-sel? omit-set? [super-type #f] [prop-value-list null]
[immutable-positions null] [mk-rec-prop-list (lambda (struct: make- ? acc mut) null)])
(let ([num-fields (length fields)]
[acc/mut-makers (let loop ([l fields][n 0])
(if (null? l)
null
(let ([mk-one
(lambda (acc?)
(list
`(,(if acc?
'make-struct-field-accessor
'make-struct-field-mutator)
,(if acc? 'acc 'mut)
,n ',(car l))))])
(append
(if omit-sel?
null
(mk-one #t))
(if omit-set?
null
(mk-one #f))
(loop (cdr l) (add1 n))))))]
[extra-props (mk-rec-prop-list 'struct: 'make- '? 'acc 'mut)])
`(let-values ([(struct: make- ? acc mut)
(make-struct-type ',name ,super-type ,num-fields 0 #f
,prop-value-list (current-inspector)
#f ,immutable-positions)])
(values struct:
make-
?
,@acc/mut-makers)))))
(define build-struct-expand-info
(lambda (name-stx fields omit-sel? omit-set? base-name base-getters base-setters)
(let* ([names (build-struct-names name-stx fields omit-sel? omit-set?)])
(build-struct-expand-info* names name-stx fields omit-sel? omit-set? base-name base-getters base-setters))))
(define build-struct-expand-info*
(lambda (names name-stx fields omit-sel? omit-set? base-name base-getters base-setters)
(let* ([flds (cdddr names)]
[every-other (lambda (l)
(let loop ([l l])
(cond
[(null? l) null]
[(null? (cdr l)) (list (car l))]
[else (cons (car l) (loop (cddr l)))])))]
[add-#f (lambda (omit? base)
(if omit?
(if (let loop ([l base])
(cond
[(null? l) #t]
[(not (car l)) #f]
[else (loop (cdr l))]))
(append base '(#f)))
base))]
[qs (lambda (x) (if (eq? x #t)
x
(and x `((syntax-local-certifier) (quote-syntax ,x)))))])
`(list-immutable
,(qs (car names))
,(qs (cadr names))
,(qs (caddr names))
(list-immutable
,@(reverse (if omit-sel?
null
(map qs (if omit-set? flds (every-other flds)))))
,@(map qs (add-#f omit-sel? base-getters)))
(list-immutable
,@(reverse (if omit-set?
null
(map qs (if omit-sel?
flds
(every-other (if (null? flds)
null
(cdr flds)))))))
,@(map qs (add-#f omit-set? base-setters)))
,(qs base-name)))))
(define (struct-declaration-info? x)
(define (identifier/#f? x)
(or (not x)
(identifier? x)))
(define (id/#f-list? id? x)
(or (null? x)
(and (pair? x)
(if (null? (cdr x))
(identifier/#f? (car x))
(and (id? (car x))
(id/#f-list? id? (cdr x)))))))
(and (list? x)
(= (length x) 6)
(identifier/#f? (car x))
(identifier/#f? (cadr x))
(identifier/#f? (caddr x))
(id/#f-list? identifier? (list-ref x 3))
(id/#f-list? identifier/#f? (list-ref x 4))
(or (eq? #t (list-ref x 5)) (identifier/#f? (list-ref x 5)))))
;; ----------------------------------------
(define struct-info-type-id car)
(define struct-info-constructor-id cadr)
(define struct-info-predicate-id caddr)
(define struct-info-accessor-ids cadddr)
(define struct-info-mutator-ids (lambda (x) (list-ref x 4)))
(define (get-stx-info orig-stx super-id defined-names)
;; Looks up super info, if needed, and builds compile-time info for the
;; new struct; called by all three forms, but does only half the work
;; if `defined-names' is #f.
;; If `expr?' is #t, then generate an expression to build the info,
;; otherwise build the info directly.
(let ([qs (lambda (x) #`((syntax-local-certifier) (quote-syntax #,x)))]
[every-other (lambda (l)
(let loop ([l l][r null])
(cond
[(null? l) r]
[(null? (cdr l)) (cons (car l) r)]
[else (loop (cddr l) (cons (car l) r))])))]
[super-info (and super-id
(syntax-local-value super-id (lambda () #f)))])
(when super-id
;; Did we get valid super-info ?
(when (or (not (struct-declaration-info? super-info))
(not (struct-info-type-id super-info)))
(raise-syntax-error
#f
(if (struct-declaration-info? super-info)
"parent struct information does not include a type for subtyping"
(format "parent struct type not defined~a"
(if super-info
(format " (~a does not name struct type information)"
(syntax-e super-id))
"")))
orig-stx
super-id)))
;; Generate the results:
(values
super-info
(if defined-names
(let-values ([(initial-gets initial-sets)
(if super-info
(values (map qs (struct-info-accessor-ids super-info))
(map qs (struct-info-mutator-ids super-info)))
(values null null))]
[(fields) (cdddr defined-names)]
[(wrap) (lambda (x) #`(list-immutable #,@x))])
(wrap
(list-immutable (qs (car defined-names))
(qs (cadr defined-names))
(qs (caddr defined-names))
(wrap
(apply
list-immutable
(append (map qs (every-other fields))
initial-gets)))
(wrap
(apply
list-immutable
(append (map qs (if (null? fields)
null
(every-other (cdr fields))))
initial-sets)))
(if super-id
(qs super-id)
#t))))
#f))))
(define (make-core make-make-struct-type orig-stx defined-names super-info name field-names)
#`(let-values ([(type maker pred access mutate)
#,(make-make-struct-type orig-stx name defined-names super-info)])
(values type maker pred
#,@(let loop ([field-names field-names][n 0])
(if (null? field-names)
null
(list* #`(make-struct-field-accessor access #,n '#,(car field-names))
#`(make-struct-field-mutator mutate #,n '#,(car field-names))
(loop (cdr field-names) (add1 n))))))))
(define (generate-struct-declaration orig-stx
name super-id field-names
context
make-make-struct-type)
(let ([defined-names (build-struct-names name field-names #f #f name)])
(let-values ([(super-info stx-info) (get-stx-info orig-stx super-id defined-names)])
(let ([result
#`(begin
(define-values
#,defined-names
#,(make-core make-make-struct-type orig-stx defined-names super-info name field-names))
(define-syntaxes (#,name)
#,stx-info))])
(if super-id
(syntax-property result
'disappeared-use
(syntax-local-introduce super-id))
result))))))