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Cookbook/Compilers and interpreters

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(first step to turn this page from an arbitrary tutorial to a cookbook chapter)
(Checking Types)
Line 10: Line 10:
Prelude> :t "Hello"
Prelude> :t "Hello"
"Hello" :: [Char]
"Hello" :: [Char]
Haskell has the following types defined in the [[Prelude]].
    Int        -- bounded, word-sized integers
    Integer    -- unbounded integers
    Double      -- floating point values
    Char        -- characters
    String      -- equivalent to [Char], strings are lists of characters
    ()          -- the unit type
    Bool        -- booleans
    [a]        -- lists
    (a,b)      -- tuples / product types
    Either a b  -- sum types
    Maybe a    -- optional values

Revision as of 08:11, 31 August 2009


2 GHCi

3 Checking Types

To check the type of an expression or function, use the command `:t'

Prelude> :t x
x :: Integer
Prelude> :t "Hello"
"Hello" :: [Char]