1 files changed, 19 insertions, 0 deletions
diff --git a/sample/sort/qsort.in b/sample/sort/qsort.in
new file mode 100644
index 0000000..523d7d8
--- /dev/null
+++ b/sample/sort/qsort.in
@@ -0,0 +1,19 @@
+// Quick sort
+
+// Rules
+qsort(ret) >< [] => ret~[];
+qsort(ret) >< (int x):xs =>
+	Append(ret, x:right)~left, part(smaller, larger, x)~xs,
+	qsort(left)~smaller, qsort(right)~larger;
+
+// Note: `Append' is implemented as the following built-in agent:
+// Append(ret, b)~a  -->  ret ~ (a++b)
+
+part(smaller, larger, int x) >< [] => smaller~[], larger~[];
+part(smaller, larger, int x) >< (int y):ys
+| y<x => smaller~(y:cnt), part(cnt, larger, x)~ys
+| _   => larger~(y:cnt), part(smaller, cnt, x)~ys;
+
+// Nets
+qsort(ret)~[3,6,1,9,2];
+ret;
+\ No newline at end of file