A-M baby

Task/Determine-if-a-string-is-numeric/Modula-3/determine-if-a-string-is-numeric.mod3

@@ -0,0 +1,25 @@
+MODULE Numeric EXPORTS Main;
+
+IMPORT IO, Fmt, Text;
+
+PROCEDURE isNumeric(s: TEXT): BOOLEAN =
+  BEGIN
+    FOR i := 0 TO Text.Length(s) DO
+      WITH char = Text.GetChar(s, i) DO
+        IF i = 0 AND char = '-' THEN
+          EXIT;
+        END;
+        IF char >= '0' AND char <= '9' THEN
+          EXIT;
+        END;
+        RETURN FALSE;
+      END;
+    END;
+    RETURN TRUE;
+  END isNumeric;
+
+BEGIN
+  IO.Put("isNumeric(152) = " & Fmt.Bool(isNumeric("152")) & "\n");
+  IO.Put("isNumeric(-3.1415926) = " & Fmt.Bool(isNumeric("-3.1415926")) & "\n");
+  IO.Put("isNumeric(Foo123) = " & Fmt.Bool(isNumeric("Foo123")) & "\n");
+END Numeric.