A-M baby

Task/Apply-a-callback-to-an-array/Modula-3/apply-a-callback-to-an-array.mod3

@@ -0,0 +1,26 @@
+MODULE Callback EXPORTS Main;
+
+IMPORT IO, Fmt;
+
+TYPE CallBack = PROCEDURE (a: CARDINAL; b: INTEGER);
+     Values = REF ARRAY OF INTEGER;
+
+VAR sample := ARRAY [1..5] OF INTEGER {5, 4, 3, 2, 1};
+    callback := Display;
+
+PROCEDURE Display(loc: CARDINAL; val: INTEGER) =
+  BEGIN
+    IO.Put("array[" & Fmt.Int(loc) & "] = " & Fmt.Int(val * val) & "\n");
+  END Display;
+
+PROCEDURE Map(VAR values: ARRAY OF INTEGER; size: CARDINAL; worker: CallBack) =
+  VAR lvalues := NEW(Values, size);
+  BEGIN
+    FOR i := FIRST(lvalues^) TO LAST(lvalues^) DO
+      worker(i, values[i]);
+    END;
+  END Map;
+
+BEGIN
+  Map(sample, NUMBER(sample), callback);
+END Callback.