How to print a warning/error message from my own module?

Question

I would like to print a warning/error message from my own module. Of course I could use Print["WARNING: my warning"] but in all the output this would be barely visible. Ideally my user defined message would appear in the same style as those produced by Mathematica built-in functions.

This is covered well in the documentation here: Messages. – dionys Sep 19 '15 at 14:09 — dionys, Sep 19 '15 at 14:09
Seems I didn't scroll down to the essential information. – highsciguy Sep 19 '15 at 14:17 — highsciguy, Sep 19 '15 at 14:17

score 1 · Accepted Answer · answered Sep 19 '15 at 14:18

You can do this using Mathematica's built-in message system; also, I'd suggest looking through Mathematica's package development documentation and tutorials, as these commonly go hand-in-hand; here is one starting place.

As for the specific question, here is an example:

MyFunction::argerr = "Bad argument given to MyFunction: `1`";
MyFunction[x_Integer] := Mod[x^2, x+1];
MyFunction[x_] := (
  Message[MyFunction::argerr, x];
  $Failed);

MyFunction[10]

1

MyFunction["abc"]

MyFunction::argerr: Bad argument given to MyFunction: abc
$Failed

How to print a warning/error message from my own module?

1 Answers1