('! #t)
('= #t)
('bool->int #t)
+ ('print #t)
(else #f)))
(cond
((list? x)
('let 'let)
('lambda 'lambda)
('closure 'closure) ; only available in codegen
+ ('static-string 'static-string) ; only available in codegen
(else 'app)))
((builtin? x) 'builtin)
((symbol? x) 'var)
((integer? x) 'int-literal)
- ((boolean? x) 'bool-literal)))
+ ((boolean? x) 'bool-literal)
+ ((string? x) 'string-literal)))
(define (ast-traverse f x)
(case (ast-type x)
('let `(let ,(map (lambda (x) (list (car x) (f (cadr x))))
(let-bindings x))
- ,@(map f (let-body e))))
+ ,@(map f (let-body x))))
('app (map f x))
- ('lambda `(lambda ,(lambda-args x) ,(f lambda-body)))
+ ('lambda `(lambda ,(lambda-args x) ,(f (lambda-body x))))
('if `(if ,@(map f (cdr x))))
(else x)))
+(define (ast-collect f x)
+ (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)))]
+ ['app (append (f x)
+ (fold-map inner x))]
+ ['lambda (append (f x)
+ (inner (lambda-body x)))]
+ ['if (append (f x)
+ (fold-map inner (cdr x)))]
+ [else (f x)]))
+
(define let-bindings cadr)
(define let-body cddr)
; for use elsewhere
(define lambda-args cadr)
(define lambda-body caddr)
+
+; utils
+(define (fold-map f x) (fold-left append '() (map f x)))
+(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))))