[bitc-dev] RFI: deeply immutable functions

[Swaroop Sridhar]

M. Scott Doerrie wrote:
> Ok, I hurridly misread this.  The di-fn type is a more general 
> solution.  Somehow I had read constructor.
> 
> Would this mean that di-fn is itself some sort of type class?  (di-fn 
> T.arg T.result) should be usable where (fn T.arg T.result) is required.  
> Of course, this isn't expressible in the current system as our type 
> classes only involve methods of fn types.  This is probably incorrect, 
> but could we think of di-fn as the following:
> 
> (deftypeclass (di-fn 'a 'b)
>    (super (fn 'a 'b)))
> 
> Of course, this is not user-definable as it's a known type to check for 
> deep imutability in the compiler.
> 

di-fn in a property of the function that the compiler needs to enforce 
wrt its definition. So, I think it is best viewed as a primitive.

Swaroop.