    -- File created: 2009-01-17

    -- |A number of primitives from which complete 'Pattern's may be constructed.
    --
    -- Using this together with the functions provided by the 'Monoid' instance of
    -- 'Pattern' allows for direct manipulation of 'Pattern's beyond what can be
    -- done with just the 'compile' family of functions. And of course you don't
    -- have to go via 'String's if you use these.
    module System.FilePath.Glob.Primitive
       ( literal
       , singleWildcard, wildcard, recursiveWildcard
       , charRange, numberRange
       ) where

    import System.FilePath (isPathSeparator, isExtSeparator)

    import System.FilePath.Glob.Base (Pattern(..), Token(..), optimize)

    -- |A 'Pattern' which matches the given 'String' literally.
    --
    -- Handles any embedded path and extension separators.
    literal :: String -> Pattern
    literal = optimize . Pattern . map f
     where
       f c | isPathSeparator c = PathSeparator
           | isExtSeparator c  = ExtSeparator
           | otherwise         = Literal c

    -- |Matches any single character except a path separator: corresponds to the
    -- @?@ operator.
    singleWildcard :: Pattern
    singleWildcard = Pattern [NonPathSeparator]

    -- |Matches any number of characters up to a path separator: corresponds to the
    -- @*@ operator.
    wildcard :: Pattern
    wildcard = Pattern [AnyNonPathSeparator]

    -- |Matches any number of characters including path separators: corresponds to
    -- the @**/@ operator.
    recursiveWildcard :: Pattern
    recursiveWildcard = Pattern [AnyDirectory]

    -- |Matches a single character if it is within the (inclusive) range in any
    -- 'Right' or if it is equal to the character in any 'Left'. Corresponds to the
    -- @[]@, @[^]@ and @[!]@ operators.
    --
    -- If the given 'Bool' is 'False', the result of the match is inverted: the
    -- match succeeds if the character does /not/ match according to the above
    -- rules.
    charRange :: Bool -> [Either Char (Char,Char)] -> Pattern
    charRange b rs = optimize $ Pattern [CharRange b rs]

    -- |Matches a number in the given range, which may be open, half-open, or
    -- closed. Corresponds to the @\<\>@ operator.
    numberRange :: Maybe Integer -> Maybe Integer -> Pattern
    numberRange a b = Pattern [OpenRange (fmap show a) (fmap show b)]