+(load "utils.scm")
+
(define (ast-type x)
(define (builtin? x)
(case x
('if 'if)
('let 'let)
('lambda 'lambda)
+ ('case 'case)
('closure 'closure) ; only available in codegen
('static-string 'static-string) ; only available in codegen
('stack 'stack) ; only available in codegen (tag that value is passed via stack)
((builtin? x) 'builtin)
((symbol? x) 'var)
((integer? x) 'int-literal)
- ((boolean? x) 'bool-literal)
((string? x) 'string-literal)))
(define (ast-traverse f x)
('app (map f x))
('lambda `(lambda ,(lambda-args x) ,(f (lambda-body x))))
('if `(if ,@(map f (cdr x))))
- ('stack `(stack ,(cadr x) ,(map f (caddr x))))
+ ('case `(case ,(f (case-switch x))
+ ,@(map (lambda (x)
+ (list (car x) (f (cadr x))))
+ (case-cases x))))
+ ('stack `(stack ,(cadr x) ,(f (caddr x))))
(else x)))
(define (ast-collect f x)
(inner (lambda-body x)))]
['if (append (f x)
(flat-map inner (cdr x)))]
+ ['case (append (f x)
+ (inner (case-switch x))
+ (flat-map inner (map cadr (case-cases x))))]
['stack (append (f x)
(inner (caddr x)))]
[else (f x)]))
(define (ast-find p x)
(define (inner y) (ast-find p y))
- (define (any p x) (fold-left
- (lambda (acc y) (if acc #t (p y)))
- #f
- x))
- (define (either . fs)
- (if (null? fs) #f
- (if (car fs) (car fs)
- (apply either (cdr fs)))))
(case (ast-type x)
- ['let (either (p x)
+ ['let (or (p x)
(any inner (let-bindings x))
(any inner (let-body x)))]
- ['app (either (p x)
+ ['app (or (p x)
(any inner x))]
- ['lambda (either (p x)
+ ['lambda (or (p x)
(inner (lambda-body x)))]
- ['if (either (p x) (any inner (cdr x)))]
- ['stack (either (p x) (inner (caddr x)))]
+ ['if (or (p x) (any inner (cdr x)))]
+ ['case (or (p x)
+ (any inner (map cadr (case-cases x)))
+ (inner (case-switch x)))]
+ ['stack (or (p x) (inner (caddr x)))]
[else (p x)]))
-(define (let-bindings e)
- (define (pattern-match binding body)
- (if (eqv? (ast-type binding) 'var)
- (list (cons binding body))
- (let* ([constructor (car binding)]
- [destructor (lambda (i) (dtor-name constructor i))])
- (flat-map (lambda (y i)
- (pattern-match y `((,(destructor i) ,@body))))
- (cdr binding)
- (range 0 (length (cdr binding)))))))
- (flat-map (lambda (x) (pattern-match (car x) (cdr x))) (cadr e)))
+(define let-bindings cadr)
(define let-body cddr)
+(define case-switch cadr)
+(define case-cases cddr)
+
+(define (constructor? data-layouts x)
+ (and (eqv? (ast-type x) 'var)
+ (assoc x (flat-map cdr data-layouts))))
+
+(define (all-cases data-layouts type)
+ (let ([sums (assoc type data-layouts)])
+ (if sums
+ (flat-map (lambda (sum)
+ (let* ([sum-name (car sum)]
+ [products (cdr sum)]
+ [product-cases (map (lambda (y) (all-cases data-layouts y)) products)])
+ (if (null? product-cases)
+ (list sum-name) ; singletons aren't enclosed in a list [(foo x) 42] vs [foo 42]
+ (apply combinations (cons (list sum-name) product-cases)))))
+ (cdr sums))
+ '(:binding))))
+
+ ; does a cover b
+(define (case-covers? data-layouts a b)
+ (let ([a-binding? (and (eqv? (ast-type a) 'var) (not (constructor? data-layouts a)))])
+ (cond
+ [(eqv? ':binding b) a-binding?]
+ [a-binding? #t]
+ ; a literal/singleton
+ [(eqv? (ast-type b) 'var) (eqv? b a)]
+ ; two different constructors
+ [(not (eqv? (car a) (car b))) #f]
+ ; two same constructors
+ [else
+ (all (map (lambda (p q)
+ (case-covers? data-layouts p q))
+ (cdr a) (cdr b)))])))
+
+(define (verify-cases data-layouts annotated-program)
+
+ ;; (define (check-pattern switch-type pat)
+
+ ;; (define (impossible-match)
+ ;; (error "Can't pattern match ~a with ~a" switch-type (ann-expr pat)))
+
+ ;; (if (assoc switch-type data-layouts)
+ ;; (begin
+ ;; (let ([sums (cdr (assoc switch-type data-layouts))])
+ ;; (unless (eqv? (ast-type (ann-expr pat)) 'var) (impossible-match))
+ ;; (unless (assoc (car (ann-expr pat)) sums) (impossible-match))
+ ;; (unless
+ ;; )
+ ;; (begin
+ ;; (unless (assoc switch-type allowed-match-ast-types)
+ ;; (error #f "Can't pattern match on ~a" switch-type))
+
+ ;; (let ([allowed (cdr (assoc switch-type allowed-match-ast-types))])
+ ;; (unless (assoc (ast-type (ann-expr pat)) allowed) (impossible-match)))))))
+
+
+ (let ([expr (ann-expr annotated-program)])
+ (case (ast-type expr)
+ ['case
+ (let* ([switch-type (ann-type (case-switch expr))]
+ [cases (map car (case-cases expr))]
+ [case-covered?
+ (lambda (x) (any (lambda (y) (case-covers? data-layouts y x)) cases))])
+ (unless (all (map case-covered? (all-cases data-layouts switch-type)))
+ (error #f "not all cases covered")))]
+ [else (ast-traverse (lambda (x) (verify-cases data-layouts x)) expr)])))
+
+
+ ; (let ([(foo a b) (foo 123 345)]) a)
+ ; |
+ ; v
+ ; (let ([a (foo~0 (foo 123 345)]
+ ; [b (foo~1 (foo 123 345)]) a)
+(define (expand-pattern-matches program)
+ (define (go x)
+ (define (let-pattern-match binding)
+ (let ([binding-name (car binding)]
+ [body (cadr binding)])
+ (if (eqv? (ast-type binding-name) 'var)
+ (list (list binding-name body))
+
+ (let* ([sum-name (car binding-name)]
+ [destructor (lambda (i) (dtor-name sum-name i))]
+ [products (cdr binding-name)]
+
+ [data-layouts (program-data-layouts program)]
+
+ [type (data-tor-type data-layouts sum-name)]
+
+ [sums (cdr (assoc type data-layouts))]
+ [sum (assoc sum-name sums)]
+
+ [expected-number (length (cdr sum))])
+
+ ; assert that we only do a let pattern match on an ADT with exactly one sum
+ (when (not (= 1 (length sums)))
+ (error #f (format "Cannot pattern match a ~a in a let since it has ~a possible constructors"
+ type
+ (length sums))))
+
+ ; assert that there is the correct number of bindings
+ (when (not (= (length products)
+ expected-number))
+ (error #f (format "Got ~a bindings: expected ~a for ~a"
+ (length products)
+ expected-number
+ binding)))
+
+ (flat-map (lambda (y i)
+ (let-pattern-match (list y `(,(destructor i) ,body))))
+ products
+ (range 0 (length products)))))))
+
+ (case (ast-type x)
+ ['let `(let ,(flat-map let-pattern-match (let-bindings x))
+ ,@(map go (let-body x)))]
+ [else (ast-traverse go x)]))
+ (program-map-exprs go program))
+
(define (lambda? x)
(and (list? x) (eq? (car x) 'lambda)))
-
(define (statement-type x)
(cond
[(and (list? x)
(filter (lambda (x) (eqv? (statement-type x) 'defines))
program))
+(define (program-map-exprs f program)
+ (map (lambda (x)
+ (case (statement-type x)
+ ['expr (f x)]
+ [else x]))
+ program))
+
(define (program-body program)
; hack to have multi-expression bodies
`(let ()
,@(filter (lambda (x) (eqv? (statement-type x) 'expr))
program)))
+(define (data-tor-type data-layouts tor)
+ (let* ([tors (flat-map data-tors data-layouts)]
+ [info (cadr (assoc tor tors))])
+ (car info)))
-
- ; gets both constructors and destructors
+ ; a data tor is either a constructor or destructor for an ADT
+ ; data-tors returns constructors and destructors for a data-layout
; (data A (foo Int Bool)
; (bar Bool))
; |
; v
- ; (foo . (constructor . (abs Int (abs Bool A))))
- ; (foo~0 . (0 . (abs A Int)))
- ; (foo~1 . (1 . (abs A Bool)))
- ; (bar . (constructor . (abs Bool A)))
- ; (bar~0 . (0 . (abs A Bool)))
+ ; (foo . ((A foo constructor) . (abs Int (abs Bool A))))
+ ; (foo~0 . ((A foo 0 Int) . (abs A Int)))
+ ; (foo~1 . ((A foo 1 Bool) . (abs A Bool)))
+ ; (bar . ((A bar constructor) . (abs Bool A)))
+ ; (bar~0 . ((A bar 0 Bool) . (abs A Bool)))
+ ; ------+-------------------------------------
+ ; tor | info | type
(define (data-tors data-layout)
(define (constructor-type t products)
(fold-right (lambda (x acc) `(abs ,x ,acc)) t products))
(define (destructor ctor-name prod-type part-type index)
- (let ([name (dtor-name ctor-name index)])
- (cons name (cons index `(abs ,prod-type ,part-type)))))
+ (let* ([name (dtor-name ctor-name index)]
+ [info (list prod-type ctor-name index part-type)])
+ (cons name (cons info `(abs ,prod-type ,part-type)))))
(let ([type-name (car data-layout)]
[ctors (cdr data-layout)])
(let* ([ctor-name (car ctor)]
[products (cdr ctor)]
- [maker (cons ctor-name (cons 'constructor (constructor-type type-name products)))]
+ [maker (cons ctor-name (cons (list type-name ctor-name 'constructor) (constructor-type type-name products)))]
[dtors (map (lambda (t i) (destructor ctor-name type-name t i))
products
ctors)))
; creates a type environment for a given adt definition
-(define (data-tors-env data-layout)
+(define (data-tors-type-env data-layout)
(map (lambda (x) (cons (car x) (cddr x))) (data-tors data-layout)))
(define (dtor-name ctor-name index)
(strong-connect v)))
(car graph)))
result))
-
-
- ; utils
-
-(define (range s n)
- (if (= 0 n) '()
- (append (range s (- n 1))
- (list (+ s (- n 1))))))
-
-(define (flat-map f . xs) (fold-left append '() (apply map (cons f xs))))
-(define (repeat x n) (if (<= n 0) '()
- (cons x (repeat x (- n 1)))))
-
-
-(define-syntax push!
- (syntax-rules ()
- ((_ s x) (set! s (cons x s)))))
-
-(define-syntax pop!
- (syntax-rules ()
- ((_ s) (let ([x (car s)])
- (set! s (cdr s))
- x))))
projects / scheme.git / blobdiff