std.string and std.algorithm: what to do?

[Andrei Alexandrescu]

Daniel Keep wrote:
> 
> Steven Schveighoffer wrote:
>> On Thu, 14 May 2009 09:55:08 -0400, Andrei Alexandrescu
>> <SeeWebsiteForEmail at erdani.org> wrote:
>>
>>> Also, I dislike the signature int find() that returns -1 if not found.
>>> Time and again experience shows that find() returning a range is much
>>> better in real code because it works seamlessly when the
>>> substring/element was not found (no more need for an extra test!)
>> Ech, returning -1 is the bane of Java and C#.  The return value should
>> be the end of the string, regardless of whether it is a range or index. 
>> I could never understand the mentality of returning -1 versus end of
>> string.
>>
>> -Steve
> 
> int idx = find(str);
> if( idx == -1 ) doStuff;
> 
> - or -
> 
> if( idx == str.length ) doStuff;

I think Steve's point is that often you want to do something like:

auto before = str[0 .. find(str, something)];

or

auto after = str[find(str, something) .. $];

which behave nicely at limit conditions (when something isn't found). In 
contrast, the version with -1 needs a separate varible and a test - a mess.


Andrei