racket/collects/scheme/contract/regions.ss
Stevie Strickland a7ff1cba83 Add definition checks back.
svn: r16377
2009-10-19 23:45:06 +00:00

602 lines
29 KiB
Scheme

#lang scheme/base
(provide define-struct/contract
define/contract
with-contract)
(require (for-syntax scheme/base
scheme/list
scheme/struct-info
syntax/define
syntax/kerncase
(prefix-in a: "private/helpers.ss"))
scheme/splicing
"private/arrow.ss"
"private/base.ss"
"private/guts.ss")
;; These are useful for all below.
(define-syntax (verify-contract stx)
(syntax-case stx ()
[(_ name x) (a:known-good-contract? #'x) #'x]
[(_ name x) #'(coerce-contract name x)]))
;; id->contract-src-info : identifier -> syntax
;; constructs the last argument to the -contract, given an identifier
(define-for-syntax (id->contract-src-info id)
#`(list (make-srcloc #,id
#,(syntax-line id)
#,(syntax-column id)
#,(syntax-position id)
#,(syntax-span id))
#,(format "~s" (syntax->datum id))))
;
;
;
; ; ;;; ; ;
; ; ; ;
; ; ; ; ; ;
; ;; ; ;;; ;;;; ; ; ;; ;;; ; ;;; ;;; ; ;; ;;;; ; ; ;;; ;;; ;;;;
; ; ;; ; ; ; ; ;; ; ; ; ; ; ; ; ; ;; ; ; ;; ; ; ; ; ;
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
; ; ; ;;;;;; ; ; ; ; ;;;;;; ; ; ; ; ; ; ; ; ;;;; ; ;
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
; ;; ; ;;;; ; ; ; ; ;;;; ; ;;; ;;; ; ; ;; ; ;;;;; ;;; ;;
; ;
; ;
;
;; (define/contract id contract expr)
;; defines `id' with `contract'; initially binding
;; it to the result of `expr'. These variables may not be set!'d.
(define-syntax (define/contract define-stx)
(when (eq? (syntax-local-context) 'expression)
(raise-syntax-error 'define/contract
"used in expression context"
define-stx))
(syntax-case define-stx ()
[(_ name)
(raise-syntax-error 'define/contract
"no contract or body"
define-stx)]
[(_ name contract-expr)
(raise-syntax-error 'define/contract
"expected a contract expression and a definition body, but found only one expression"
define-stx)]
[(_ name+arg-list contract #:freevars args . body)
(identifier? #'args)
(raise-syntax-error 'define/contract
"expected list of identifier/contract pairs"
#'args)]
[(_ name+arg-list contract #:freevars (arg ...) #:freevar x c . body)
(syntax/loc define-stx
(define/contract name+arg-list contract #:freevars (arg ... [x c]) . body))]
[(_ name+arg-list contract #:freevar x c . body)
(syntax/loc define-stx
(define/contract name+arg-list contract #:freevars () #:freevar x c . body))]
[(_ name+arg-list contract #:freevars args body0 body ...)
(begin
(when (and (identifier? #'name+arg-list)
(not (null? (syntax->list #'(body ...)))))
(raise-syntax-error 'define/contract
"multiple expressions after identifier and contract"
#'(body ...)))
(let-values ([(name body-expr)
(if (identifier? #'name+arg-list)
(values #'name+arg-list #'body0)
(normalize-definition
(datum->syntax #'define-stx (list* 'define/contract #'name+arg-list
#'body0 #'(body ...)))
#'lambda #t #t))])
(with-syntax ([name name]
[body-expr body-expr]
[type (if (identifier? #'name+arg-list) 'definition 'function)])
(syntax/loc define-stx
(with-contract #:type type name
([name contract])
#:freevars args
(define name body-expr))))))]
[(_ name+arg-list contract body0 body ...)
(syntax/loc define-stx
(define/contract name+arg-list contract #:freevars () body0 body ...))]))
(define-syntax (define-struct/contract stx)
(define-struct field-info (stx ctc [mutable? #:mutable] auto?))
(define-struct s-info (auto-value-stx transparent? def-stxs? def-vals?))
(define syntax-error
(lambda v
(apply raise-syntax-error 'define-struct/contract v)))
(define (build-struct-names name field-infos)
(let ([name-str (symbol->string (syntax-case name ()
[id (identifier? #'id)
(syntax-e #'id)]
[(sub super)
(syntax-e #'sub)]))])
(list*
(syntax-case name ()
[id (identifier? #'id) #'id]
[(sub super) #'sub])
(datum->syntax
name
(string->symbol
(string-append "struct:" name-str)))
(datum->syntax
name
(string->symbol
(string-append "make-" name-str)))
(datum->syntax
name
(string->symbol
(string-append name-str "?")))
(apply append
(for/list ([finfo field-infos])
(let ([field-str (symbol->string (syntax-e (field-info-stx finfo)))])
(cons (datum->syntax
name
(string->symbol
(string-append name-str "-" field-str)))
(if (field-info-mutable? finfo)
(list (datum->syntax
name
(string->symbol
(string-append "set-" name-str "-" field-str "!"))))
null))))))))
(define (build-contracts stx pred field-infos)
(list* (syntax/loc stx any/c)
(syntax/loc stx any/c)
(apply append
(for/list ([finfo field-infos])
(let ([field-ctc (field-info-ctc finfo)])
(cons (quasisyntax/loc stx
(-> #,pred #,field-ctc))
(if (field-info-mutable? finfo)
(list
(quasisyntax/loc stx
(-> #,pred #,field-ctc void?)))
null)))))))
(define (check-field f ctc)
(let ([p-list (syntax->list f)])
(if p-list
(begin
(when (null? p-list)
(syntax-error "expected struct field" f))
(unless (identifier? (car p-list))
(syntax-error "expected identifier" f))
(let loop ([rest (cdr p-list)]
[mutable? #f]
[auto? #f])
(if (null? rest)
(make-field-info (car p-list) ctc mutable? auto?)
(let ([elem (syntax-e (car rest))])
(if (keyword? elem)
(cond
[(eq? elem '#:mutable)
(begin (when mutable?
(syntax-error "redundant #:mutable"
(car rest)))
(loop (cdr rest) #t auto?))]
[(eq? elem '#:auto)
(begin (when auto?
(syntax-error "redundant #:mutable"
(car rest)))
(loop (cdr rest) mutable? #t))]
[else (syntax-error "expected #:mutable or #:auto"
(car rest))])
(syntax-error "expected #:mutable or #:auto"
(car rest)))))))
(if (identifier? f)
(make-field-info f ctc #f #f)
(syntax-error "expected struct field" f)))))
(define (check-kwds kwd-list field-infos)
(let loop ([kwds kwd-list]
[auto-value-stx #f]
[mutable? #f]
[transparent? #f]
[def-stxs? #t]
[def-vals? #t])
(if (null? kwds)
(make-s-info auto-value-stx transparent? def-stxs? def-vals?)
(let ([kwd (syntax-e (car kwds))])
(when (not (keyword? kwd))
(syntax-error "expected a keyword"
(car kwds)))
(cond
[(eq? kwd '#:auto-value)
(when (null? (cdr kwds))
(syntax-error "expected a following expression"
(car kwds)))
(loop (cddr kwds) (cadr kwds)
transparent? mutable? def-stxs? def-vals?)]
;; let arbitrary properties through
[(eq? kwd '#:property)
(when (null? (cdr kwds))
(syntax-error "expected a property"
(car kwds)))
(when (null? (cddr kwds))
(syntax-error "expected a value for the property"
(car kwds)))
(loop (cdddr kwds) auto-value-stx
mutable? transparent? def-stxs? def-vals?)]
[(eq? kwd '#:mutable)
(when mutable?
(syntax-error "redundant #:mutable"
(car kwds)))
(for ([finfo field-infos])
(set-field-info-mutable?! finfo #t))
(loop (cdr kwds) auto-value-stx
#t transparent? def-stxs? def-vals?)]
[(eq? kwd '#:transparent)
(when transparent?
(syntax-error "redundant #:transparent"
(car kwds)))
(loop (cdr kwds) auto-value-stx
mutable? #t def-stxs? def-vals?)]
[(eq? kwd '#:omit-define-syntaxes)
(when (not def-stxs?)
(syntax-error "redundant #:omit-define-syntaxes"
(car kwds)))
(loop (cdr kwds) auto-value-stx
transparent? mutable? #f def-vals?)]
[(eq? kwd '#:omit-define-values)
(when (not def-vals?)
(syntax-error "redundant #:omit-define-values"
(car kwds)))
(loop (cdr kwds) auto-value-stx
transparent? mutable? def-stxs? #f)]
[else (syntax-error "unexpected keyword"
(car kwds))])))))
(syntax-case stx ()
[(_ name ([field ctc] ...) kwds ...)
(let ([fields (syntax->list #'(field ...))])
(unless (or (identifier? #'name)
(syntax-case #'name ()
[(x y) (and (identifier? #'x)
(identifier? #'y))]
[_ #f]))
(syntax-error "expected identifier for struct name or a sub-type relationship (subtype supertype)"
#'name))
(let* ([field-infos (map check-field fields (syntax->list #'(ctc ...)))]
[sinfo (check-kwds (syntax->list #'(kwds ...)) field-infos)]
[names (build-struct-names #'name field-infos)]
[pred (cadddr names)]
[ctcs (build-contracts stx pred field-infos)]
[super-fields (syntax-case #'name ()
[(child parent)
(let ([v (syntax-local-value #'parent (lambda () #f))])
(unless (struct-info? v)
(raise-syntax-error #f "identifier is not bound to a structure type" stx #'parent))
(let ([v (extract-struct-info v)])
(cadddr v)))]
[else '()])])
(let-values ([(non-auto-fields auto-fields)
(let loop ([fields field-infos]
[nautos null]
[autos null])
(if (null? fields)
(values (reverse nautos)
(reverse autos))
(if (field-info-auto? (car fields))
(loop (cdr fields)
nautos
(cons (car fields) autos))
(if (null? autos)
(loop (cdr fields)
(cons (car fields) nautos)
autos)
(syntax-error "non-auto field after auto fields"
(field-info-stx (car fields)))))))])
(with-syntax ([ctc-bindings
(if (s-info-def-vals? sinfo)
(map list (cddr names)
ctcs)
null)]
[orig stx]
[struct-name (syntax-case #'name ()
[id (identifier? #'id) #'id]
[(id1 super) #'id1])]
[(auto-check ...)
(let* ([av-stx (if (s-info-auto-value-stx sinfo)
(s-info-auto-value-stx sinfo)
#'#f)]
[av-id (datum->syntax av-stx
(string->symbol
(string-append (syntax-case #'name ()
[id (identifier? #'id)
(symbol->string (syntax-e #'id))]
[(id1 super)
(symbol->string (syntax-e #'id1))])
":auto-value"))
av-stx)])
(for/list ([finfo auto-fields])
#`(let ([#,av-id #,av-stx])
(contract #,(field-info-ctc finfo)
#,av-id
'(struct name)
'cant-happen
#,(id->contract-src-info av-id)))))]
;; a list of variables, one for each super field
[(super-fields ...) (generate-temporaries super-fields)]
;; the contract for a super field is any/c becuase the
;; super constructor will have its own contract
[(super-contracts ...) (for/list ([i (in-list super-fields)])
(datum->syntax stx 'any/c))]
[(non-auto-contracts ...)
(map field-info-ctc
(filter (lambda (f)
(not (field-info-auto? f)))
field-infos))]
;; the make-foo function. this is used to make the contract
;; print the right name in the blame
[maker (caddr names)]
[(non-auto-name ...)
(map field-info-stx non-auto-fields)])
(syntax/loc stx
(begin
(define-values () (begin auto-check ... (values)))
(define (guard super-fields ... non-auto-name ... struct-name)
(values super-fields ... non-auto-name ...))
(define blame-id
(current-contract-region))
(with-contract #:type struct struct-name
ctc-bindings
(define-struct/derived orig name (field ...)
kwds ...
#:guard (contract (-> super-contracts ... non-auto-contracts ... symbol? any)
guard
(current-contract-region) blame-id
#'maker)))))))))]
[(_ name . bad-fields)
(identifier? #'name)
(syntax-error "expected a list of field name/contract pairs"
#'bad-fields)]
[(_ . body)
(syntax-error "expected a structure name"
#'body)]))
;
;
; ; ;
; ; ; ; ;
; ; ; ; ;
; ; ; ; ; ;;;; ; ;;; ;;; ;;; ; ;;; ;;;; ; ;; ;;;; ;;; ;;;;
; ; ; ; ; ; ;; ; ; ; ; ; ;; ; ; ;; ; ; ; ; ;
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;;; ; ;
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;;; ; ; ;
; ; ; ; ; ; ; ; ; ;;;; ; ; ; ; ; ; ; ; ; ; ;
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ;
; ; ; ; ;;; ; ; ;;; ;;; ; ; ;;; ; ;;;; ; ;;; ;;;
;
;
;
(define-for-syntax (make-contracted-id-transformer id contract-stx pos-blame-id neg-blame-id)
(make-set!-transformer
(lambda (stx)
(syntax-case stx (set!)
[(set! i arg)
(quasisyntax/loc stx
(set! #,id
(contract #,contract-stx
arg
#,neg-blame-id
#,pos-blame-id
#,(id->contract-src-info id))))]
[(f arg ...)
(quasisyntax/loc stx
((contract #,contract-stx
#,id
#,pos-blame-id
#,neg-blame-id
#,(id->contract-src-info id))
arg ...))]
[ident
(identifier? (syntax ident))
(quasisyntax/loc stx
(contract #,contract-stx
#,id
#,pos-blame-id
#,neg-blame-id
#,(id->contract-src-info id)))]))))
(define-for-syntax (check-and-split-with-contracts args)
(let loop ([args args]
[protected null]
[protections null])
(cond
[(null? args)
(values protected protections)]
[(let ([lst (syntax->list (car args))])
(and (list? lst)
(= (length lst) 2)
(identifier? (first lst))
lst))
=>
(lambda (l)
(loop (cdr args)
(cons (first l) protected)
(cons (second l) protections)))]
[else
(raise-syntax-error 'with-contract
"expected (identifier contract)"
(car args))])))
(define-syntax (with-contract-helper stx)
(syntax-case stx ()
[(_ ())
#'(begin)]
[(_ (p0 p ...))
(raise-syntax-error 'with-contract
"no definition found for identifier"
#'p0)]
[(_ (p ...) body0 body ...)
(let ([expanded-body0 (local-expand #'body0
(syntax-local-context)
(kernel-form-identifier-list))])
(define (filter-ids to-filter to-remove)
(filter (λ (i1)
(not (memf (λ (i2)
(bound-identifier=? i1 i2))
to-remove)))
to-filter))
(syntax-case expanded-body0 (begin define-values define-syntaxes)
[(begin sub ...)
(syntax/loc stx
(with-contract-helper (p ...) sub ... body ...))]
[(define-syntaxes (id ...) expr)
(let ([ids (syntax->list #'(id ...))])
(with-syntax ([def expanded-body0]
[unused-ps (filter-ids (syntax->list #'(p ...)) ids)])
(with-syntax ()
(syntax/loc stx
(begin def (with-contract-helper unused-ps body ...))))))]
[(define-values (id ...) expr)
(let ([ids (syntax->list #'(id ...))])
(with-syntax ([def expanded-body0]
[unused-ps (filter-ids (syntax->list #'(p ...)) ids)])
(syntax/loc stx
(begin def (with-contract-helper unused-ps body ...)))))]
[else
(quasisyntax/loc stx
(begin #,expanded-body0
(with-contract-helper (p ...) body ...)))]))]))
(define-syntax (with-contract stx)
(when (eq? (syntax-local-context) 'expression)
(raise-syntax-error 'with-contract
"used in expression context"
stx))
(syntax-case stx ()
[(_ #:type type etc ...)
(not (identifier? #'type))
(raise-syntax-error 'with-contract
"expected identifier for type"
#'type)]
[(_ #:type type args etc ...)
(not (identifier? #'args))
(raise-syntax-error 'with-contract
"expected identifier for blame"
#'args)]
[(_ #:type type blame (arg ...) #:freevars (fv ...) #:freevar x c . body)
(identifier? #'x)
(syntax/loc stx
(with-contract #:type type blame (arg ...) #:freevars (fv ... [x c]) . body))]
[(_ #:type type blame (arg ...) #:freevars (fv ...) #:freevar x c . body)
(raise-syntax-error 'with-contract
"use of #:freevar with non-identifier"
#'x)]
[(_ #:type type blame (arg ...) #:freevars (fv ...) . body)
(and (identifier? #'blame)
(identifier? #'type))
(let*-values ([(intdef) (syntax-local-make-definition-context)]
[(ctx) (list (gensym 'intdef))]
[(cid-marker) (make-syntax-introducer)]
[(free-vars free-ctcs)
(check-and-split-with-contracts (syntax->list #'(fv ...)))]
[(protected protections)
(check-and-split-with-contracts (syntax->list #'(arg ...)))])
(define (add-context stx)
(let ([ctx-added-stx (local-expand #`(quote #,stx)
ctx
(list #'quote)
intdef)])
(syntax-case ctx-added-stx ()
[(_ expr) #'expr])))
(when (eq? (syntax-local-context) 'expression)
(raise-syntax-error 'with-contract
"cannot use in an expression context"
stx))
(let ([dupd-id (check-duplicate-identifier protected)])
(when dupd-id
(raise-syntax-error 'with-contract
"identifier appears twice in exports"
dupd-id)))
(syntax-local-bind-syntaxes protected #f intdef)
(syntax-local-bind-syntaxes free-vars #f intdef)
(internal-definition-context-seal intdef)
(with-syntax ([blame-stx #''(type blame)]
[blame-id (car (generate-temporaries (list #t)))]
[(free-var ...) free-vars]
[(free-var-id ...) (add-context #`#,free-vars)]
[(free-ctc-id ...) (map cid-marker free-vars)]
[(free-ctc ...) (map (λ (c v)
(syntax-property c 'inferred-name v))
free-ctcs
free-vars)]
[(free-src-info ...) (map id->contract-src-info free-vars)]
[(ctc-id ...) (map cid-marker protected)]
[(ctc ...) (map (λ (c v)
(syntax-property (add-context c) 'inferred-name v))
protections
protected)]
[(p ...) protected]
[(marked-p ...) (add-context #`#,protected)]
[(src-info ...) (map (compose id->contract-src-info add-context) protected)])
(with-syntax ([new-stx (add-context #'(splicing-syntax-parameterize
([current-contract-region (λ (stx) #'blame-stx)])
. body))])
(quasisyntax/loc stx
(begin
(define-values (free-ctc-id ...)
(values (verify-contract 'with-contract free-ctc) ...))
(define blame-id
(current-contract-region))
(define-values ()
(begin (contract free-ctc-id
free-var
blame-id
'cant-happen
free-src-info)
...
(values)))
(define-syntaxes (free-var-id ...)
(values (make-contracted-id-transformer
(quote-syntax free-var)
(quote-syntax free-ctc-id)
(quote-syntax blame-id)
(quote-syntax blame-stx)) ...))
(with-contract-helper (marked-p ...) new-stx)
(define-values (ctc-id ...)
(values (verify-contract 'with-contract ctc) ...))
(define-values ()
(begin (contract ctc-id
marked-p
blame-stx
'cant-happen
src-info)
...
(values)))
(define-syntaxes (p ...)
(values (make-contracted-id-transformer
(quote-syntax marked-p)
(quote-syntax ctc-id)
(quote-syntax blame-stx)
(quote-syntax blame-id)) ...)))))))]
[(_ #:type type blame (arg ...) #:freevar x c . body)
(syntax/loc stx
(with-contract #:type type blame (arg ...) #:freevars ([x c]) . body))]
[(_ #:type type blame (arg ...) . body)
(syntax/loc stx
(with-contract #:type type blame (arg ...) #:freevars () . body))]
[(_ #:type type blame bad-args etc ...)
(raise-syntax-error 'with-contract
"expected list of identifier and/or (identifier contract)"
#'bad-args)]
[(_ #:type type blame)
(raise-syntax-error 'with-contract
"only blame"
stx)]
[(_ etc ...)
(syntax/loc stx
(with-contract #:type region etc ...))]))