Data commit

Task/Mutual-recursion/Draco/mutual-recursion.draco

@@ -0,0 +1,26 @@
+/* We need to predeclare M if we want F to be able to see it.
+ * This is done using 'extern', same as if it had been in a
+ * different compilation unit. */
+extern M(byte n) byte;
+
+/* Mutually recursive functions */
+proc F(byte n) byte:
+    if n=0 then 1 else n - M(F(n-1)) fi
+corp
+
+proc M(byte n) byte:
+    if n=0 then 0 else n - F(M(n-1)) fi
+corp
+
+/* Show the first 16 values of each */
+proc nonrec main() void:
+    byte i;
+
+    write("F:");
+    for i from 0 upto 15 do write(F(i):2) od;
+    writeln();
+
+    write("M:");
+    for i from 0 upto 15 do write(M(i):2) od;
+    writeln()
+corp