Initial data commit

Task/Gray-code/M2000-Interpreter/gray-code.m2000

@@ -0,0 +1,29 @@
+Module Code32  (&code(), &decode()){
+      Const d$="{0::-2} {1:-6} {2:-6} {3:-6} {4::-2}"
+      For i=0 to 32
+            g=code(i)
+            b=decode(g)
+            Print format$(d$, i, @bin$(i), @bin$(g), @bin$(b), b)
+      Next
+      // static function
+      Function bin$(a)
+            a$=""
+            Do n= a mod 2 : a$=if$(n=1->"1", "0")+a$ : a|div 2 : Until a==0
+            =a$
+      End Function
+}
+Module GrayCode {
+      Module doit (&a(), &b()) { }
+      Function GrayEncode(a) {
+            =binary.xor(a, binary.shift(a,-1))
+      }
+      Function GrayDecode(a) {
+            b=0
+            Do b=binary.xor(a, b) : a=binary.shift(a,-1) : Until a==0
+            =b
+      }
+      // pass 2 functions to Code32
+      doit &GrayEncode(), &GrayDecode()
+}
+// pass Code32 to GrayCode in place of doit
+GrayCode ; doit as  Code32