X-Git-Url: http://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=ast.scm;h=a0899192e21a1d44b0fe3296e380604133a3f1d2;hp=2ffad975f66f1ec4fbca3f32f095e484658ed726;hb=91145e54f41ee88f1e279a80430b3f5ed4e7a8c6;hpb=43f8c4631ae0a3163c780e7511a96f6b05054544

diff --git a/ast.scm b/ast.scm
index 2ffad97..a089919 100644
--- a/ast.scm
+++ b/ast.scm
@@ -1,11 +1,38 @@
-(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 let-body cddr)
@@ -18,15 +45,3 @@
 ; for use elsewhere
 (define lambda-args cadr)
 (define lambda-body caddr)
-
-(define (var? x)
-  (and (not (list? x)) (symbol? x)))
-
-(define (builtin? x)
-  (case x
-    ('+ #t)
-    ('- #t)
-    ('* #t)
-    ('! #t)
-    ('bool->int #t)
-    (else #f)))