[clean-list] Funny identifiers starting with double colon

[John van Groningen]

Hi Vag,

You wrote:

>Compiler eats
>
>:: A = ::: | .:: | ?:: | ::? | :::!!! |  | :::.
>
>but complains on each
>
>:: A = ::!
>:: A = !::
>:: A = ::.
>
>i.e. every identifier starting with ! or with :: (excluding :::) considered incorrect.
>
>Is this intended behavior?

Yes, except for ::A = !::
 
::! , ::. and ::* are parsed as :: followed by !, . or *.
This makes it possible to write:

f ::!Int -> Int
f ::.Int -> Int
f ::*Int -> Int

Other symbols starting with :: are allowed, for example ::?

Type names may not start with a !, because ! is used as strictness annotation.
The type definition:

:: A = !::

is correct, and is allowed by the current development version of the compiler.
However,

:: A :== :!!

is incorrect.

Kind regards,

John van Groningen