('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))))
+ ('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)))
(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 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
; [b (foo~1 (foo 123 345)]) a)
(define (expand-pattern-matches program)
(define (go x)
- (define (pattern-match binding)
+ (define (let-pattern-match binding)
(let ([binding-name (car binding)]
[body (cadr binding)])
(if (eqv? (ast-type binding-name) 'var)
binding)))
(flat-map (lambda (y i)
- (pattern-match (list y `(,(destructor i) ,body))))
+ (let-pattern-match (list y `(,(destructor i) ,body))))
products
(range 0 (length products)))))))
+
(case (ast-type x)
- ['let `(let ,(flat-map pattern-match (let-bindings 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))
; |
; v
; (foo . ((A foo constructor) . (abs Int (abs Bool A))))
- ; (foo~0 . ((A foo 0) . (abs A Int)))
- ; (foo~1 . ((A foo 1) . (abs A Bool)))
+ ; (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) . (abs A Bool)))
+ ; (bar~0 . ((A bar 0 Bool) . (abs A Bool)))
; ------+-------------------------------------
; tor | info | type
(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 (list prod-type ctor-name 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)])
projects / scheme.git / blobdiff