40 lines
1.3 KiB
Haskell
40 lines
1.3 KiB
Haskell
{-# OPTIONS_HADDOCK ignore-exports #-}
|
|
|
|
module Parser.PathParser where
|
|
|
|
import Control.Applicative
|
|
import Parser.Core
|
|
import Algorithms.RangeSearch.QuadTree (Quad(NW, NE, SW, SE), Orient(North, South, West, East))
|
|
|
|
|
|
-- |Parse a string such as "ne, n, sw, e" into
|
|
-- [Quad NE, Orient North, Quad SW, Orient East].
|
|
stringToQuads :: String -> [Either Quad Orient]
|
|
stringToQuads str = case runParser parsePath str of
|
|
Nothing -> []
|
|
Just xs -> fst xs
|
|
where
|
|
parsePath = zeroOrMore ((parseQuad <|> parseOrient)
|
|
<* zeroOrMore (char ',')
|
|
<* spaces)
|
|
|
|
|
|
-- |Parses a string that represents a single squad into the
|
|
-- QuadOrOrient ADT.
|
|
parseQuad :: Parser (Either Quad Orient)
|
|
parseQuad =
|
|
const (Left NW) <$> (string "nw" <|> string "NW")
|
|
<|> const (Left NE) <$> (string "ne" <|> string "NE")
|
|
<|> const (Left SW) <$> (string "sw" <|> string "SW")
|
|
<|> const (Left SE) <$> (string "se" <|> string "SE")
|
|
|
|
|
|
-- |Parses a string that represents a single Orientation into the
|
|
-- QuadOrOrient ADT.
|
|
parseOrient :: Parser (Either Quad Orient)
|
|
parseOrient =
|
|
const (Right North) <$> (string "n" <|> string "N")
|
|
<|> const (Right South) <$> (string "s" <|> string "S")
|
|
<|> const (Right West) <$> (string "w" <|> string "W")
|
|
<|> const (Right East) <$> (string "e" <|> string "E")
|