indexOf's return val upon not found

[Nick Sabalausky]

"Nick Sabalausky" <a at a.a> wrote in message 
news:i2r1nt$1egu$1 at digitalmars.com...
> Wouldn't it be better if std.string's indexOf/lastIndexOf returned 
> haystack.length instead of -1 to indicate "not found"? The -1 is never 
> really useful, but needs like this are fairly common:
>
> auto slice = str[str.indexOf(needle)..$];
>
> Which gives you an empty string if needle doesn't exist, which I find is 
> usually exactly what I want anyway (and consistent with find's semantics, 
> IIRC). But with the current semantics of indexOf/lastIndexOf, the risk of 
> the occasional -1 forces the clean code above to be turned into something 
> like this:
>
> auto needleIndex = str.indexOf(needle);
> auto slice = needleIndex==-1? "" : str[needleIndex..$];
>
> Yuck.
>

Another case where indexOf is currently awkward is if you want a slice of 
str that strips off everything up until the first of a few possiblities. If 
indexOf returned haystack.length upon not found, you could just do something 
like this:

auto startIndex = min(str.indexOf("a"), str.indexOf("b"), str.indexOf("c"));
auto slice = str[startIndex..$];

With the current indexOf, the correct code is, well, quite a bit messier. 
And this is one case where find doesn't provide quite as nice of a solution 
either (unlike my first example which could probably be replaced entirely by 
find).