"if not" condition check (for data validation)

[Denis]

On Thursday, 18 June 2020 at 00:43:40 UTC, Stanislav Blinov wrote:
>
> if( ! (configfile.isFile && configfile.extension == ".conf") )
>
> ?

That does indeed clean up the compound logic. One is still left 
with:

   if( !(
   if( !
   if( !(
   if( !
    :

I was hoping to get away from all the `not`s too.