Re: Receiving type information from environment instead of hardcoding.

In light of the mentioned patch, I prefer to freeze my activity about the unification of Nat and Natural up to the merging this patch. After that, I am going to rebase my branch and make MR. Thank you, Ben! пн, 15 июн. 2020 г. в 00:32, Ben Gamari :

Rinat Stryungis writes:

...

Hi. I have a question about a possible way of unification of Nat and Natural. I've almost done that, but only in case of using integer-gmp. If I use integer-simple there is a completely different definition of Natural.

How I construct now naturalTyCon (to make `naturalTy` to use it instead of `typeNatKind`) :

```naturalTyCon :: TyCon naturalTyCon = pcTyCon naturalTyConName Nothing [] [natSDataCon,natJDataCon]

natSDataCon :: DataCon natSDataCon = pcDataCon natSDataConName [] [wordPrimTy] naturalTyCon

etc... ``` Now I have to check`DynFlags` in a few places to reimplement `naturalTyCon` in case of using `integer-simple`.

Is there a way to avoid hardcoding of `naturalTy`? My colleague said that it would be nice to get `naturalTy` from an environment by something like `lookupTyCon`, but there are many functions whose don't use any environment like functions from `typeNatTyCons` list in `GHC.Builtin.Types.Literals`.

Now I am going to use `DynFlags` checking, but it looks like an ugly way...

Note that all of this will be moot in a matter of days. The ghc-bignum patch, which will ship in 8.12, removes integer-simple and uses a consistent number representation across its various supported backends.

In light of this, if I were you I would probably just settle for a hack in the meantime.

Cheers,

- Ben

-- Best regards. Rinat Striungis