Now that we have visible type application, we could stop using these Proxy arguments, thus class Bits a where ... bitSizeMaybe' :: Maybe Int And you invoke it by saying bitSizeMaybe @ T rather than bitSizeMaybe (Proxy :: Proxy T) Looks like a straight win to me. Simon | -----Original Message----- | From: Libraries [mailto:libraries-bounces@haskell.org] On Behalf Of M | Farkas-Dyck | Sent: 14 December 2017 03:48 | To: libraries@haskell.org | Subject: Proposal: add `Proxy`fied versions of `bitSizeMaybe` and | `finiteBitSize` | | I propose to add the following methods to `Bits` and `FiniteBits` | classes: | | class Bits a where | ... | | bitSizeMaybe' :: Proxy a -> Maybe Int | | class FiniteBits b where | ... | | finiteBitSize' :: Proxy b -> Int | | Rationale: working with an arbitrary `Bits a => a`, one may not have a | value of type `a` as argument to `bitSizeMaybe` or `finiteBitSize`, | and writing `undefined` makes me feel dirty. | _______________________________________________ | Libraries mailing list | Libraries@haskell.org | https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmail.h | askell.org%2Fcgi- | bin%2Fmailman%2Flistinfo%2Flibraries&data=04%7C01%7Csimonpj%40microsof | t.com%7Cd88222263d04465efcf608d542a6473f%7C72f988bf86f141af91ab2d7cd01 | 1db47%7C1%7C0%7C636488204282827644%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4 | wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwifQ%3D%3D%7C- | 1&sdata=GUcUpHRarbB8uky4m%2Fve1l3ZbtPnDIndzPM9FG5Jj44%3D&reserved=0