Phrogz schrieb:
> b) Why do you think it's generally useful? I think such a method would
> have helped me only once or twice in all my programming years.

There is only one reason: It is a standard function used in mathematics and 
nearly everybody knows a function names "sign" or "sgn" from other programming 
languages.

I think that the code for this method is still there in the kernel.

> c) You can implement that more compactly (if not more efficiently) as:
> 
> irb(main):001:0> class Numeric; def sign; self <=> 0; end; end

It was only an example to describe what I mean. I have no suggestions for an 
implementation in the Ruby kernel.

I only think, that a mathematical standard function should be available.

Wolfgang N?dasi-Donner