(define (inner y) (ast-collect f y))
(case (ast-type x)
['let (append (f x)
- (fold-map inner (let-bindings x))
- (fold-map inner (let-body x)))]
+ (flat-map inner (let-bindings x))
+ (flat-map inner (let-body x)))]
['app (append (f x)
- (fold-map inner x))]
+ (flat-map inner x))]
['lambda (append (f x)
(inner (lambda-body x)))]
['if (append (f x)
- (fold-map inner (cdr x)))]
+ (flat-map inner (cdr x)))]
[else (f x)]))
-(define let-bindings cadr)
+(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)
+ (any inner (let-bindings x))
+ (any inner (let-body x)))]
+ ['app (either (p x)
+ (any inner x))]
+ ['lambda (either (p x)
+ (inner (lambda-body x)))]
+ ['if (either (p x) (any inner (cdr x)))]
+ [else (p x)]))
+
+(define (let-bindings e)
+ (define (pattern-match x body)
+ (if (eqv? (ast-type x) 'var)
+ (list (cons x body))
+ (let* ([constructor (car x)]
+ [destructor (lambda (i) `(destruct ,i ,constructor))])
+ (flat-map (lambda (y i)
+ (pattern-match y (list (destructor i) body)))
+ (cdr x)
+ (range 0 (length (cdr x)))))))
+ (flat-map (lambda (x) (pattern-match (car x) (cdr x))) (cadr e)))
(define let-body cddr)
(define (lambda? x)
(and (list? x) (eq? (car x) 'lambda)))
+
+(define (statement-type x)
+ (cond
+ [(and (list? x)
+ (eqv? (car x) 'data)) 'data]
+ [(and (list? x)
+ (eqv? (car x) 'define)) 'define]
+ [else 'expr]))
+
+(define (program-datas program)
+ (filter (lambda (x) (eqv? (statement-type x) 'data))
+ program))
+
+(define (program-defines program)
+ (filter (lambda (x) (eqv? (statement-type x) 'defines))
+ program))
+
+(define (program-body program)
+ `(let ()
+ ,@(filter (lambda (x) (eqv? (statement-type x) 'expr))
+ program)))
+
; for use in normalized form
(define lambda-arg caadr)
; for use elsewhere
(define lambda-body caddr)
; utils
-(define (fold-map f x) (fold-left append '() (map f x)))
+(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)))))