Move scheme compiler into a separate directory.

1 files changed, 64 insertions, 0 deletions

diff --git a/csc/list.csc b/csc/list.csc
new file mode 100644
index 0000000..f425146
--- /dev/null
+++ b/csc/list.csc
@@ -0,0 +1,64 @@
+(define-library (csc list)
+  (export
+    enumerate
+    filter
+    intercalate
+    revappend
+    split-at
+    take)
+  (import (scheme base)
+          (only (csc match)
+            match))
+  (begin
+
+
+    (define (take n xs)
+      (let loop ((n n)
+                 (xs xs)
+                 (acc '()))
+        (if (or (not (positive? n)) (null? xs))
+            (reverse acc)
+          (loop (- n 1) (cdr xs) (cons (car xs) acc)))))
+
+
+    (define (split-at n xs)
+      (let loop ((n n)
+                 (xs xs)
+                 (acc '()))
+        (if (or (not (positive? n)) (null? xs))
+            (values (reverse acc) xs)
+          (loop (- n 1) (cdr xs) (cons (car xs) acc)))))
+
+
+    (define (revappend a b)
+      (let loop ((xs a)
+                 (acc b))
+        (if (null? xs)
+            acc
+          (loop (cdr xs) (cons (car xs) acc)))))
+
+
+    (define (intercalate x l)
+      (match l
+        ('() '())
+        ((_) l)
+        ((head . tail) (cons head (cons x (intercalate x tail))))))
+
+
+    (define (enumerate l)
+      (let loop ((i 0)
+                 (l l))
+        (match l
+          ('() '())
+          ((head . tail) (cons (cons i head) (loop (+ 1 i) tail))))))
+
+
+    (define (filter p l)
+      (let loop ((l l)
+                 (acc '()))
+        (match l
+          ('() (reverse acc))
+          ((x . xs)
+           (if (p x)
+             (loop xs (cons x acc))
+             (loop xs acc))))))))