[Ur] How to design JSON interface?

[Adam Chlipala]

Marc Weber wrote:
> I'd like to implement toJson and fromJson which can read typed values
> from json representation and back automatically.
>
> I still don't know how to represent this in urweb:
>    

I'm sorry if I didn't say this clearly before: The way I would implement 
this involves modifying the compiler in a not especially modular way.  
This would naturally be a mirror of the current support for encoding 
arbitrary values into URLs with the new format I made up.  I'll be very 
impressed if you're able to figure out how to implement this.

I still don't understand yet why you want JSON.  Can you explain?  Maybe 
I can talk you out of it. :-)

> I found:
> - the eq class in basis.ur - but the implementation of mkEq is written
>    in ml (?)
>    

Yes, though this particular case would be easy to implement in Ur code.  
The issue is just with automatic, generic handling of records and datatypes.

> - the classes in tests/ - but those methods don't take a type of t
>    worse: When copy pasting  type_classMod2.ur into my own .ur file it
>    fails to compile:
>    

I mask out the tests when building distributions for a reason: a lot of 
them don't compile anymore. :-)