How to find documentation of hard-to-google keywords and symbols

[bearophile]

dnspies:

> I still don't know where to find documentation for "is" (which 
> I just found out in another forum post is overloaded for 
> dynamic arrays).  Can users overload the meaning of "is" 
> themselves?

Here you find info on the D language:
http://dlang.org/spec.html

"is" is an operator, so it's an expression, so you find it here:
http://dlang.org/expression

Bye,
bearophile