From: Wes Gamble <weyus@...>
Date: 2006-09-30T17:06:38+09:00
Subject: Integer division with / - request explanation of behavior

Today I discovered the difference in the meaning of the / (arithmetic 
divide) method depending on whether it's caller is an integer or a 
float.

I discovered that I had to cast the calling number explicitly to a float 
and it seemed totally non-intuitive to me.

A couple of points:

1) I just discovered that this behavior exists in Java and C as well. 
Which, frankly, I didn't even realize.  Sigh.

2) I've read some other posts and people have mentioned the notion of 
type purity with respect to this.  I don't see why that's a problem. 
When one divides two integers, one isn't asking for one of the integer 
arguments to be cast to a float, they're asking for the result of 
dividing two integers.  Since when is it not allowable for a method to 
take arguments of a given type and return a result of a different type?

A couple of questions:

1) I see that there is a divmod operator in Ruby that returns the 
quotient and remainder of a division.  Why is the overridden / operator 
necessary when there is already a way to get int1 DIV int2 by using 
int1.divmod(int2)[0]?

2) Is the reason for the behavior of "/" is that this is the behavior of 
"/" in C?  Why is it that way in C?

Thanks,
Wes

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