What is "FilterResult" type?

[cym13 via Digitalmars-d-learn]

On Tuesday, 8 September 2015 at 11:08:59 UTC, Bahman Movaqar 
wrote:
> However, I have made this a strict practice of mine to specify 
> the full signature of my public API.  I suppose, if I want to 
> be pedantic, I have to realise the lazy value first and pass 
> the resulting array out.  Is this correct?

Yes, using an array will work here, but if you are designing a 
library then I'd prefer that you don't force me into being non 
lazy where I could be just because you want to have a clear type: 
laziness is a virtue, reducing possibilities isn't a great idea.

What I would do is a designated wrapper template which will give 
you a clear type while still being lazy: exactly what 
FilterResult and MapResult are.