From: timr <timrandg@...>
Date: 2010-08-23T17:51:02+09:00
Subject: assert "foo"[3] != "foo"[3,1]...revisited

consider the following irb session;

>> "foo"[0]
=> "f"
>> "foo"[1]
=> "o"
>> "foo"[2]
=> "o"
>> "foo"[3]
=> nil
>> "foo"[4]
=> nil

>> "foo"[0,3]
=> "foo"
>> "foo"[1,3]
=> "oo"
>> "foo"[2,3]
=> "o"
#note the following weird case!!!
>> "foo"[3,3]
=> ""　　#this should be nil in my mind, "foo"[3] is nil, and taking
three characters is still nil.
>> "foo"[4,3]
=> nil

So, to summarize, when indexing a position beyond the length of a
string, ruby returns nil. But when indexing a slice beyond the length
of a string, ruby returns an empty string "" for the first index
beyond and then nil.

I don't like that this passes
assert "foo"[3] != "foo"[3,1]

Matz, you are so smart, but this does not follow the principle of
least surprise!!! こんなことはへんじゃないすか。

I would appreciate it if anyone can explain how this might make
sense...but please only try if you really believe it is a defensible
behavior for the language.
Thanks,
Tim