std.string.indexOf with an optional start-at parameter?

[Robert Jacques]

On Sun, 03 Apr 2011 13:39:40 -0400, Aleksandar Ružičić  
<ruzicic.aleksandar at gmail.com> wrote:

> I needed std.string.indexOf to accept start position in the string to
> start the search at. I was really surprised when I realized that this
> (to me) standard parameter is "missing" (I'm used to indexOf in
> javascript, strpos in php and equivalent methods in other languages,
> which support start offset parameter).
>
> There might be some other function (in some other module) that does
> what I want but I wasn't able to find it (I find D's documentation not
> easy to search and read), so I've copied indexOf to my module and
> added wanted functionality:
>
> https://gist.github.com/900589
>
> now, I'm able to write, for example:
>
> auto pos = indexOf(haystack, '$', 10); // will starts search at 11th
> char in haystack

auto pos = indexOf(haystack[10..$], '$') + 10;

> and
>
> auto pos = indexOf(haystack, '$', -5); // will starts search at 5th
> char from the end

auto pos = indexOf(haystack[$-5..$], '$') + haystack.length-5;

> My question is: is there a reason why there is no this functionality
> in phobos (maybe there's some language feature I'm not aware of?) and
> if no such reason exists, would it be possible to add it in future
> version of phobos/dmd?

Yes, the language feature is called slicing. See above. Also, you may want  
to look at the various find methods in std.algorithm. Generally, it's  
better to work with ranges/slices than indexes due to UTF's encoding  
scheme.