X-Git-Url: http://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=ast.scm;h=5064ca554bc8033bdbc0b483ac79249cd3312f73;hp=2beb94507572eafd20b586d2ce9ef3867ec63d3e;hb=844dcd052c6f551d9936693c2b4c49cf920c7051;hpb=8b8c603a6106151188bdeab95501cacaf72912d4

diff --git a/ast.scm b/ast.scm
index 2beb945..5064ca5 100644
--- a/ast.scm
+++ b/ast.scm
@@ -38,14 +38,14 @@
   (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 (ast-find p x)
@@ -70,12 +70,86 @@
     ['if (either (p x) (any inner (cdr x)))]
     [else (p x)]))
 
-(define let-bindings cadr)
+(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) (dtor-name constructor i))])
+	  (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)))
+
+					; gets both constructors and destructors
+					; (data A (foo Int Bool)
+					;         (bar Bool))
+					;        |
+					;        v
+					; (foo . (abs Int (abs Bool A)))
+					; (foo~0 . (abs A Int)
+					; (foo~1 . (abs A Bool)
+					; (bar . (abs Bool A)
+					; (bar~0 . (abs A Bool)
+
+(define (data-tors data-def)
+  (define (constructor-type t products)
+    (fold-right (lambda (x acc) `(abs ,x ,acc)) t products))
+
+  (define (destructor ctor-name prod-type part-type index)
+    (let ([name (dtor-name ctor-name index)])
+      (cons name `(abs ,prod-type ,part-type))))
+  
+  (let ([type-name (cadr data-def)]
+        [ctors (cddr data-def)])
+    (fold-right
+     (lambda (ctor acc)       
+       (let* ([ctor-name (car ctor)]
+	      [products (cdr ctor)]
+	      
+	      [maker (cons ctor-name (constructor-type type-name products))]
+	      
+	      [dtors (map (lambda (t i) (destructor ctor-name type-name t i))
+			  products
+			  (range 0 (length products)))])
+	 
+	 (cons maker (append dtors acc))))
+     '()
+     ctrs)))
+
+(define (dtor-name ctor-name index)
+  (string->symbol
+   (string-append (symbol->string ctor-name)
+		  "~"
+		  (number->string index))))
+
 ; for use in normalized form
 (define lambda-arg caadr)
 ; for use elsewhere
@@ -83,7 +157,12 @@
 (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)))))