X-Git-Url: https://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=ast.scm;h=1a4afe21f3258d829c4f305ea78fd2f804cca2ad;hp=a38a01257aea179e4638d376400fcc77e1c9318e;hb=25ef5a684dec5eedfc4e34a12b00a04e2d6b2b1b;hpb=d0e9f5296b7510fe057be4a2f9e2a31ed856652c

diff --git a/ast.scm b/ast.scm
index a38a012..1a4afe2 100644
--- a/ast.scm
+++ b/ast.scm
@@ -38,22 +38,76 @@
   (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)
+	(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
@@ -61,7 +115,12 @@
 (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)))))