['stack (either (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)
+ ; (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 x)
+ (define (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))])
+ (flat-map (lambda (y i)
+ (pattern-match (list y `(,(destructor i) ,body))))
+ (cdr binding-name)
+ (range 0 (length (cdr binding-name))))))))
+ (case (ast-type x)
+ ['let `(let ,(flat-map pattern-match (let-bindings x))
+ ,@(map expand-pattern-matches (let-body x)))]
+ [else (ast-traverse expand-pattern-matches x)]))
+
(define (lambda? x)
(and (list? x) (eq? (car x) 'lambda)))
(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 ()
(bar . (abs Bool A))
(bar~0 . (abs A Bool))))
+(test (expand-pattern-matches '(let ([(foo x y) (foo 123 234)] [z (f 123)]) x))
+ '(let ([x (foo~0 (foo 123 234))]
+ [y (foo~1 (foo 123 234))]
+ [z (f 123)])
+ x))
+
(test-types (typecheck '((lambda (x) (+ ((lambda (y) (x y 3)) 5) 2))))
'(abs (abs Int (abs Int Int)) Int))
'Int)
- ; pattern matching
-(test (let-bindings '(let ([(foo x) a]) x))
- '((x (foo~0 a))))
-
-(test (let-bindings '(let ([x (foo 42)] [(foo y) x]) x))
- '((x (foo 42))
- (y (foo~0 x))))
-
; type annotations
(test (annotate-types
; we typecheck the lambda calculus only (only single arg lambdas)
(define (typecheck prog)
- (cadr (check (init-adts-env prog) (normalize (program-body prog)))))
+ (let ([expanded (program-map-exprs expand-pattern-matches prog)])
+ (cadr (check (init-adts-env expanded) (normalize (program-body expanded))))))
; before passing annotated types onto codegen
(define ann-expr car)
(define ann-type caddr)
+
+ ; prerequisites: expand-pattern-matches
(define (annotate-types prog)
- (denormalize (program-body prog)
+ (denormalize
+ (program-body prog)
(caddr (check (init-adts-env prog)(normalize (program-body prog))))))