Core implementation of new contract datatypes.

svn: r17684
This commit is contained in:
Carl Eastlund 2010-01-17 02:54:55 +00:00
parent 4189297063
commit ff00fefb2d
2 changed files with 265 additions and 0 deletions

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#lang scheme/base
(require unstable/srcloc scheme/pretty)
(provide blame?
make-blame
blame-source
blame-guilty
blame-innocent
blame-contract
blame-value
blame-positive
blame-negative
blame-swapped?
blame-swap
raise-blame-error
current-blame-format
(struct-out exn:fail:contract:blame))
(define-struct blame [source value contract positive negative swapped?])
(define (blame-guilty b)
(if (blame-swapped? b)
(blame-negative b)
(blame-positive b)))
(define (blame-innocent b)
(if (blame-swapped? b)
(blame-positive b)
(blame-negative b)))
(define (blame-swap b)
(struct-copy blame b [swapped? (not (blame-swapped? b))]))
(define-struct (exn:fail:contract:blame exn:fail:contract) [object]
#:transparent)
(define (raise-blame-error b x fmt . args)
(raise
(make-exn:fail:contract:blame
((current-blame-format) b x (apply format fmt args))
(current-continuation-marks)
b)))
(define (default-blame-format b x custom-message)
(let* ([source-message (source-location->prefix (blame-source b))]
[guilty-message (show (blame-guilty b))]
[contract-message (show (blame-contract b))]
[value-message (if (blame-value b)
(format " on ~a" (show (blame-value b)))
"")])
(format "~a~a broke the contract ~a~a; ~a"
source-message
guilty-message
contract-message
value-message
custom-message)))
(define (show v)
(let* ([line
(parameterize ([pretty-print-columns 'infinity])
(pretty-format v))])
(if (< (string-length line) 30)
line
(parameterize ([pretty-print-print-line show-line-break]
[pretty-print-columns 50])
(pretty-format v)))))
(define (show-line-break line port len cols)
(newline port)
(if line
(begin (display " " port) 2)
0))
(define current-blame-format
(make-parameter default-blame-format))

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#lang scheme/base
(require "blame.ss")
(provide prop:contract
contract-struct?
contract-struct-name
contract-struct-first-order
contract-struct-projection
contract-struct-stronger?
prop:flat-contract
flat-contract-struct?
contract-property?
build-contract-property
flat-contract-property?
build-flat-contract-property
simple-contract
simple-flat-contract)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Contract Property
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define-struct contract-property [ name first-order projection stronger ]
#:omit-define-syntaxes)
(define build-contract-property
(build-property make-contract-property 'anonymous-contract))
(define (contract-property-guard prop info)
(unless (contract-property? prop)
(raise
(make-exn:fail:contract
(format "~a: expected a contract property; got: ~e"
'prop:contract
prop)
(current-continuation-marks))))
prop)
(define-values [ prop:contract contract-struct? contract-struct-property ]
(make-struct-type-property 'prop:contract contract-property-guard))
(define (contract-struct-name c)
(let* ([prop (contract-struct-property c)]
[get-name (contract-property-name prop)]
[name (get-name c)])
name))
(define (contract-struct-first-order c)
(let* ([prop (contract-struct-property c)]
[get-first-order (contract-property-first-order prop)]
[first-order (get-first-order c)])
first-order))
(define (contract-struct-projection c)
(let* ([prop (contract-struct-property c)]
[get-projection (contract-property-projection prop)]
[projection (get-projection c)])
projection))
(define (contract-struct-stronger? a b)
(let* ([prop (contract-struct-property a)]
[stronger (contract-property-stronger prop)])
(stronger a b)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Flat Contract Property
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define-struct flat-contract-property [implementation]
#:omit-define-syntaxes)
(define build-flat-contract-property
(build-property (compose make-flat-contract-property make-contract-property)
'anonymous-flat-contract))
(define (flat-contract-property-guard prop info)
(unless (flat-contract-property? prop)
(raise
(make-exn:fail:contract
(format "~a: expected a flat contract property; got: ~e"
'prop:flat-contract
prop)
(current-continuation-marks))))
prop)
(define flat-contract-property->contract-property
flat-contract-property-implementation)
(define (flat-contract-property->procedure-property prop)
(let* ([impl (flat-contract-property-implementation prop)]
[get-predicate (contract-property-first-order impl)])
(lambda (c x) ((get-predicate c) x))))
(define-values [ prop:flat-contract
flat-contract-struct?
flat-contract-struct-property ]
(make-struct-type-property
'prop:flat-contract
flat-contract-property-guard
(list (cons prop:contract flat-contract-property->contract-property)
(cons prop:procedure flat-contract-property->procedure-property))))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Friendly Property Construction
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define ((build-property mk default-name)
#:name [get-name #f]
#:first-order [get-first-order #f]
#:projection [get-projection #f]
#:stronger [stronger #f])
(let* ([get-name (or get-name (lambda (c) default-name))]
[get-first-order (or get-first-order get-any?)]
[get-projection (or get-projection
(get-first-order-projection
get-name get-first-order))]
[stronger (or stronger weakest)])
(mk get-name get-first-order get-projection stronger)))
(define (get-any? c) any?)
(define (any? x) #t)
(define (weakest a b) #f)
(define ((get-first-order-projection get-name get-first-order) c)
(first-order-projection (get-name c) (get-first-order c)))
(define (((first-order-projection name first-order) b) x)
(if (first-order x)
x
(raise-blame-error b x "expected <~a>, given: ~e" name x)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Simple Contract Construction
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define-struct simple-contract [ name first-order projection stronger ]
#:omit-define-syntaxes
#:property prop:contract
(make-contract-property
(lambda (c) (simple-contract-name c))
(lambda (c) (simple-contract-first-order c))
(lambda (c) (simple-contract-projection c))
(lambda (a b) ((simple-contract-stronger a) a b))))
(define simple-contract
(build-contract make-simple-contract 'simple-contract))
(define-struct simple-flat-contract [ name first-order projection stronger ]
#:omit-define-syntaxes
#:property prop:flat-contract
(make-flat-contract-property
(make-contract-property
(lambda (c) (simple-flat-contract-name c))
(lambda (c) (simple-flat-contract-first-order c))
(lambda (c) (simple-flat-contract-projection c))
(lambda (a b) ((simple-flat-contract-stronger a) a b)))))
(define simple-flat-contract
(build-contract make-simple-flat-contract 'simple-flat-contract))
(define ((build-contract mk default-name)
#:name [name #f]
#:first-order [first-order #f]
#:projection [projection #f]
#:stronger [stronger #f])
(let* ([name (or name default-name)]
[first-order (or first-order any?)]
[projection (or projection (first-order-projection name first-order))]
[stronger (or stronger weakest)])
(mk name first-order projection stronger)))