+-----------------------------------------------------------------------------
+-- |
+-- 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 where
+module GHC.Types (Char(..), Int(..), Float(..), Double(..), IO(..)) where
import GHC.Prim
-- We need Inl etc behind the scenes for the type definitions
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 #))
+