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-- Name:     Boolean.e - Library for boolean types
-- Author:   D. Newhall
-- Created:  July 22, 2005
-- Updated:  July 27, 2005
-- License:  Public Domain
-- Intro:
--   boolean.e contains a type definition for boolean variables. Boolean
--   variables can have only two values, TRUE or FALSE. In Euphoria (like most
--   other languages without builtin support for booleans) the numeric value of
--   1 is used to represent TRUE and the numeric value of 0 is used to represent
--   FALSE.
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-- Global constants

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-- Constant: TRUE
-- Syntax:  include boolean.e
--          TRUE
-- Description: TRUE is defined as 1 which is what Euphoria uses to determine
--             that an expression is 'true' in a truth statement 
--             (if, while, etc.).
-- Example: 
--   while TRUE do
--      -- Code in loop goes on forever
--   end while
-- See Also:  FALSE
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global constant TRUE = (1 = 1)  -- Should be equal to 1


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-- Constant: FALSE
-- Syntax:  include boolean.e
--          FALSE
-- Description: FALSE is defined as 0 which is what Euphoria uses to determine
--             that an expression is 'false' in a truth statement 
--             (if, while, etc.).
-- Example:
--     running = TRUE
--
--     while running do
--         -- Code goes here
--         -- Continues running until...
--         running = FALSE
--     end while
--
-- See Also:  TRUE
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global constant FALSE = not TRUE  -- Should be equal to 0





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-- Type:     boolean
-- Author:   D. Newhall
-- Created:  July 22, 2005
--
-- Syntax:
--   include boolean.e
--   i = boolean(x)
--
-- Description:
--    Returns 1 if x is equal to either 1 (TRUE) or 0 (FALSE) otherwise it will
--    return 0.
--
-- Comments:
--    This serves to define the boolean type. You can also call it like an 
--    ordinary function to determine if an object is a boolean.
--
-- Example:
--     boolean running
--
--     running = TRUE
--
--     while running do
--         -- Code goes here
--         -- Set running to FALSE to stop.
--     end while
--
-- See Also: TRUE, FALSE
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global type boolean (integer i)

    if i = TRUE or i = FALSE then
        return TRUE
    else
        return FALSE
    end if

end type -- boolean