RAISE_APPLICATION_ERROR's Forgotten Parameter

One of my current goals is to re-read the literature I have on PL/SQL and SQL. I'm going back to the documentation and my PL/SQL books to give myself a bit of a refresher course. One of the things I came across today is something I believe is not very well known.

The built in RAISE_APPLICATION_ERROR procedure has a little-known third parameter. 

RAISE_APPLICATION_ERROR ( 
   num            IN BINARY_INTEGER,
   msg            IN VARCHAR2,
   keeperrorstack IN BOOLEAN); 

The documentation states that for the keeperrorstack parameter "If you specify TRUE, PL/SQL puts error_code on top of the error stack. Otherwise, PL/SQL replaces the error stack with error_code."

Procedure Dependencies in a Package

I was reviewing some PL/SQL development work recently and I noticed that a developer had declared some procedures in a package specification that should not have been public. When I asked why this was done the reply was that the procedures had dependencies on one another and the package body would not compile otherwise.

Here's a quick demonstration of the issue the developer was encountering.

The Greatest Word In the English Language

The most amazing word in the English language is "Why". Why do I say that? Because it forces someone to back up their claims with evidence.

Do you see what I did there? ;)