From: hfulton@...
Date: 2001-07-13T00:44:29+09:00
Subject: [ruby-talk:17732] Re: Array#sort! returns nil when array empty

> Array#sort! returns nil if the array is empty, whereas ri 
says it should
> return itself:
>      arr.sort! -> arr 

This is one of those features that I consider questionable.

The idea is that a bang-method which *doesn't* change its 
receiver will return nil to show that the receiver is unchanged.

The same happens in a case like "Hello".gsub!(/foo/,"bar") --
this returns nil also (I haven't tried it today :) though).

What makes the feature even more questionable in my mind is 
that in the case of sort!, it only returns nil for the 
pathological cases like an array of length 0 or 1. It doesn't
check arrays of arbitrary size. So even the inconsistency is
inconsistent.

Personally, I wouldn't mind seeing this feature removed... it
always bites me when I chain methods, resulting in an error
that "nil" doesn't have any such method.

And I personally never use this feature -- i.e., I never check
to see whether the receiver was really modified. I just assume
that my postcondition holds. For example, if I use gsub! to
remove commas from a string, I don't care that it didn't have
any commas to begin with. I just know that after the gsub!, it
definitely has no commas.


Hal