ghc

I want to disable warning only some block of code. I searched Google but only find file scope or global scope disable method. Using cabal file or pragma {-# OPTIONS_GHC #-} Can I disable warning for specific function? No, you can't currently in GHC 8.8.1 The {-# OPTIONS_GHC #-} pragma is file-header only and applies to the whole module. And there are no such pragmas (or other ways) to suppress warnings in specific locations. You can check the full list of pragmas in the Haskell user guide: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#pragmas The list of

Here's my code: {-# LANGUAGE TypeFamilies, TypeOperators, DataKinds, PolyKinds, FlexibleContexts, UndecidableInstances #-} module Foo where import Data.Singletons.Prelude import Data.Type.Equality data TP a b -- foldl (\(bool, r) x -> (bool && (r == x), r)) (True, head xs) xs type family Same (b :: Bool) (r :: k) (rq :: [k]) :: k where Same bool r (x ': xs) = Same (bool :&& (r == x)) r xs Same bool r '[] = TP bool r data NotEqualFailure -- converts a True result to a type type family EqResult tp where EqResult (TP 'True r) = r EqResult (TP 'False r) = NotEqualFailure data Zq q i type family

Not sure what exactly to google for this question, so I'll post it directly to SO: Variables in Haskell are immutable Pure functions should result in same values for same arguments From these two points it's possible to deduce that if you call somePureFunc somevar1 somevar2 in your code twice, it only makes sense to compute the value during the first call. The resulting value can be stored in some sort of a giant hash table (or something like that) and looked up during subsequent calls to the function. I have two questions: Does GHC actually do this kind of optimization? If it does, what is

Can the GHC-specific libraries be called the standard library? Or do only those in the Haskell 2010 report count? Many of the GHC libraries can be implemented by the functions in the Haskell report, possibly combined with C bindings. But the others are reliant on GHC-specific extensions, since the current Haskell language as defined in the language report doesn't support it. For example, can Data.Array.IO be implemented in pure standard Haskell? Is it really okay to think that GHC is Haskell? Unfortunately the Haskell community doesn't have a real consensus about what's the "standard" library.

As far as I know, a decidable type checking algorithm exists (only) for rank-2 types. Does GHC use somehow this fact, and does it have any practical implications? Is there also a notion of principal types for rank-2 types, and a type inference algorithm? If yes, does GHC use it? Are there any other advantages of rank-2 types over rank- n types? Rank2Types is a synonym for RankNTypes . So right now there are no advantages of rank-2 over rank-n. In principle type checking is decidable for rank 2 types. But, that was never going to be included in GHC (overly complicated, doesn't mix well with

I'm trying to install network and old-time with cabal-install. When I try to install either it fails with: setup.exe: The package has a './configure' script. This requires a Unix compatibility toolchain such as MinGW+MSYS or Cygwin. I do have MinGW, in fact it's the MinGW distributed along with GHC. I've also added the bin folder to my PATH. How can I fix this? what tool is the one actually running the configure files? maybe I need to get it? GHC 7.10.1 x64 cabal-install version 1.22.0.0 using version 1.22.0.0 of the Cabal library. And I'm actually on a Windows 10 pro insider preview build