What's the simplest way to read a file token by token?

[Carl Sturtivant]

On Saturday, 10 August 2013 at 17:09:29 UTC, Carl Sturtivant 
wrote:
>
> What's the simplest way in D to read a file token by token, 
> where the read tokens are D strings, and they are separated in 
> the file by arbitrary non-zero amounts of white space 
> (including spaces, tabs and newlines at a minimum)?

I couldn't find a function that did just this, and various ways I 
implemented it seemed too complex. Is there such a function in a 
D library?