WIP in let-binding pattern match stuff

diff --git a/ast.scm b/ast.scm
index 469a96f7162cb09c77dac0ed71b971dcbbd179a0..23e7723cc725a3a07b2fe5229576b92e604c34b2 100644 (file)
--- a/ast.scm
+++ b/ast.scm
@@ -71,8 +71,16 @@
     [else (p x)]))
 
 (define (let-bindings e)
     [else (p x)]))
 
 (define (let-bindings e)

-  (define (extract x)  ) ; TODO
-  (flat-map extract (cadr 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)
 (define let-body cddr)
 
 (define (lambda? x)


@@ -107,7 +115,12 @@
 (define lambda-body caddr)
 
                                        ; utils
 (define lambda-body caddr)
 
                                        ; utils

-(define (flat-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 '() (map f xs)))

 (define (repeat x n) (if (<= n 0) '()
                         (cons x (repeat x (- n 1)))))
 
 (define (repeat x n) (if (<= n 0) '()
                         (cons x (repeat x (- n 1)))))