----------------------------------------------------------------------------- -- | -- 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] {-| The character type 'Char' is an enumeration whose values represent Unicode (or equivalently ISO\/IEC 10646) characters (see <http://www.unicode.org/> for details). This set extends the ISO 8859-1 (Latin-1) character set (the first 256 charachers), which is itself an extension of the ASCII character set (the first 128 characters). A character literal in Haskell has type 'Char'. To convert a 'Char' to or from the corresponding 'Int' value defined by Unicode, use 'Prelude.toEnum' and 'Prelude.fromEnum' from the 'Prelude.Enum' class respectively (or equivalently 'ord' and 'chr'). -} 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 #))