From: Robert Klemme <shortcutter@...>
Date: 2009-05-10T03:00:30+09:00
Subject: Re: ruby string slice/[] w/ range, weird end behavior

On 09.05.2009 02:19, Gary Yngve wrote:
> On May 8, 4:47 pm, Eleanor McHugh <elea...@games-with-brains.com>
> wrote:
>> "foo"[3..3]                   => ""
> ..
>> index [3] is actually the end of the string so whilst the range  
>> accesses the string after any characters in it, it's still accessing  
>> the string in a valid range.
> 
> Maybe in the native C.  But why should that be exposed?
> And why shouldn't index[3] return "" if you are correct?

If we change perspective a bit, the behavior seems pretty naturally to 
me: if you execute this:

s = "foo"
l = s.length
(l + 2).times do |i|
   p i, s[i,l - i], s[i, 1 + l - i]
end

you get this:

0
"foo"
"foo"
1
"oo"
"oo"
2
"o"
"o"
3
""
""
4
nil
nil

In this context, returning the empty string for 3,0 seems ok - 
especially if you consider, that s[a,b] is truncated at the end of the 
string if a + b > s.length.

Kind regards

	robert