GHC.Types

ghc-prim-0.2.0.0: GHC primitives

Portability | non-portable (GHC Extensions)
Stability | internal
Maintainer | cvs-ghc@haskell.org

GHC.Types

Description

GHC type definitions. Use GHC.Exts from the base package instead of importing this module directly.

Synopsis

- data Char = C# Char#
- data Int = I# Int#
- data Float = F# Float#
- data Double = D# Double#
- newtype IO a = IO (State# RealWorld -> (#State# RealWorld, a#))

# Documentation

data Char

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`).

Constructors

C# Char# |

data 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.

Constructors

I# Int# |

data Float

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.

Constructors

F# Float# |

data Double

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.

Constructors

D# Double# |

newtype IO a

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.

Constructors

IO (State# RealWorld -> (#State# RealWorld, a#)) |