From 2dc45b818f2e8b41376fc23563c67a7ecf093323 Mon Sep 17 00:00:00 2001
From: Reid Spencer
The string 'undef' is recognized as a type-less constant that has + no specific value. Undefined values may be of any type, and be used anywhere + a constant is permitted.
-The string 'undef' is recognized as a filler that has no specified -value. Undefined values may be of any type, and be used anywhere a constant -is.
- -Undefined values are used to indicate the compiler that the program is well -defined no matter what value is used, giving it more freedom.
- +Undefined values indicate to the compiler that the program is well defined + no matter what value is used, giving the compiler more freedom to optimize. +