X-Git-Url: http://git.lukelau.me/?a=blobdiff_plain;f=ast.scm;h=469a96f7162cb09c77dac0ed71b971dcbbd179a0;hb=a64f7097fa246c19a4c69d0aad65e60378273887;hp=05716e40814287b15a67cfe7a87b1339734f13b0;hpb=64e7552f99ab98b7db77797cecfc3f34331296df;p=scheme.git

diff --git a/ast.scm b/ast.scm
index 05716e4..469a96f 100644
--- a/ast.scm
+++ b/ast.scm
@@ -1,23 +1,123 @@
-(define (app? x)
-  (and (list? x)
-       (>= (length x) 2)
-       (not (eq? (car x) 'let))
-       (not (eq? (car x) 'lambda))))
+(define (ast-type x)
+  (define (builtin? x)
+    (case x
+      ('+ #t)
+      ('- #t)
+      ('* #t)
+      ('! #t)
+      ('= #t)
+      ('bool->int #t)
+      ('print #t)
+      (else #f)))
+  (cond
+   ((list? x)
+    (case (car x)
+      ('if 'if)
+      ('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)
+   ((string? x) 'string-literal)))
 
-(define (let? x)
-  (and (list? x) (eq? (car x) 'let)))
+(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 x))))
+    ('app (map f x))
+    ('lambda `(lambda ,(lambda-args x) ,(f (lambda-body x))))
+    ('if `(if ,@(map f (cdr x))))
+    (else x)))
 
-(define let-bindings cadr)
+(define (ast-collect f x)
+  (define (inner y) (ast-collect f y))
+  (case (ast-type x)
+    ['let (append (f x)
+		  (flat-map inner (let-bindings x))
+		  (flat-map inner (let-body x)))]
+    ['app (append (f x)
+		  (flat-map inner x))]
+    ['lambda (append (f x)
+		     (inner (lambda-body x)))]
+    ['if (append (f x)
+		 (flat-map inner (cdr 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)
+		  (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 (extract x)  ) ; TODO
+  (flat-map extract (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-args cadr)
 (define lambda-body caddr)
 
-(define (var? x)
-  (and (not (list? x)) (symbol? x)))
+; utils
+(define (flat-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))))