[Ur] Repeated datatype declarations

[Ron de Bruijn]

Op 12-10-11 09:41, Gergely Buday schreef:
>> Why do datatype declarations have to be repeated in the implementation file
>> (.ur) when they are already specified in the interface file (.urs)?
>
> They serve different purposes, in the .urs file they are interface
> declarations, in the .ur file they are implementation declarations,
> this is how I see them.
>
> - Gergely
If that would be the case there would be a mechanism to mark some datatypes as 
being exported and some others as not exported. Currently, 'marking' is copying 
the whole datatype definition, which is completely against 
http://en.wikipedia.org/wiki/Don't_repeat_yourself .

The reason Ur supports meta-programming is that you can still program in a 
type-safe language while reducing code-size, but this 'feature' goes directly 
against that.

(Also, just because Standard ML does it in this way, doesn't mean it is the best 
known way to do it. )

-- 
Best regards,
   Ron de Bruijn