----------------------------------------------------------------------------- -- | -- Module : GHC.Types -- Copyright : (c) The University of Glasgow 2009 -- License : see libraries/ghc-prim/LICENSE -- -- Maintainer : cvs-ghc@haskell.org -- Stability : internal -- Portability : non-portable (GHC Extensions) -- -- GHC type definitions. -- Use GHC.Exts from the base package instead of importing this -- module directly. -- ----------------------------------------------------------------------------- {-# OPTIONS_GHC -XNoImplicitPrelude #-} module GHC.Types (Char(..), Int(..), Float(..), Double(..), IO(..)) where import GHC.Prim -- We need Inl etc behind the scenes for the type definitions import GHC.Generics () infixr 5 : data [] a = [] | a : [a] data Char = C# Char# data Int = I# Int# -- ^A fixed-precision integer type with at least the range @[-2^29 .. 2^29-1]@. -- The exact range for a given implementation can be determined by using -- 'Prelude.minBound' and 'Prelude.maxBound' from the 'Prelude.Bounded' class. -- | Single-precision floating point numbers. -- It is desirable that this type be at least equal in range and precision -- to the IEEE single-precision type. data Float = F# Float# -- | Double-precision floating point numbers. -- It is desirable that this type be at least equal in range and precision -- to the IEEE double-precision type. data Double = D# Double# {-| A value of type @'IO' a@ is a computation which, when performed, does some I\/O before returning a value of type @a@. There is really only one way to \"perform\" an I\/O action: bind it to @Main.main@ in your program. When your program is run, the I\/O will be performed. It isn't possible to perform I\/O from an arbitrary function, unless that function is itself in the 'IO' monad and called at some point, directly or indirectly, from @Main.main@. 'IO' is a monad, so 'IO' actions can be combined using either the do-notation or the '>>' and '>>=' operations from the 'Monad' class. -} newtype IO a = IO (State# RealWorld -> (# State# RealWorld, a #))