is(x = module) vs. __traits(isModule, x)

[Paul Backus]

On Wednesday, 7 October 2020 at 19:07:34 UTC, H. S. Teoh wrote:
> I'm on the fence about this one. Having to type 
> __traits(isModule,xxx) is painful.  Is it really necessary to 
> make it so hard just to check whether a symbol is a module??  
> It's not as if it's something we want to discourage.  Typing 
> is(xxx == module) is much easier, and more pleasant on the eyes.

IMO this is one of those situations where your pain is trying to 
tell you something. If using __traits syntax is so painful that 
we're willing to add hacky special cases to other language 
features in order to avoid it, maybe the message we should take 
from that is "we need to improve __traits syntax."

Here's my strawman proposal: turn all __traits into properties. A 
few before-and-after examples:

__traits(isModule, foo)
   => foo.__isModule

__traits(getMember, T, "x")
   => T.__member("x")

__traits(compiles, some(kind, of + expression))
   => (some(kind, of + expression)).__compiles