summaryrefslogtreecommitdiffhomepage
path: root/Parsers.hs
blob: 9d905544db1148d528899e31f7f2261efd99dd1f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
{-# LANGUAGE FlexibleContexts #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Xmobar.Parsers
-- Copyright   :  (c) Andrea Rossato
-- License     :  BSD-style (see LICENSE)
--
-- Maintainer  :  Andrea Rossato <andrea.rossato@unibz.it>
-- Stability   :  unstable
-- Portability :  unportable
--
-- Parsers needed for Xmobar, a text based status bar
--
-----------------------------------------------------------------------------

module Parsers
    ( parseString
    , parseTemplate
    , parseConfig
    ) where

import Config
import Commands
import Runnable
import Text.ParserCombinators.Parsec hiding ((<|>))
import qualified Text.ParserCombinators.Parsec as Parsec
import qualified Data.Map as Map

import Data.Foldable (sequenceA_)
import Data.List (find,inits,tails)
import Control.Applicative.Permutation (optAtom, runPermsSep)
import Control.Applicative hiding (many)
import Control.Monad.Writer
import Data.Either

-- | Runs the string parser
parseString :: Config -> String -> IO [(String, String)]
parseString c s =
    case parse (stringParser (fgColor c)) "" s of
      Left  _ -> return [("Could not parse string: " ++ s, fgColor c)]
      Right x -> return (concat x)

-- | Gets the string and combines the needed parsers
stringParser :: String -> Parser [[(String, String)]]
stringParser c = manyTill (textParser c <|> colorParser) eof

-- | Parses a maximal string without color markup.
textParser :: String -> Parser [(String, String)]
textParser c = do s <- many1 $
                    noneOf "<" <|>
                    ( try $ notFollowedBy' (char '<')
                                           (string "fc=" <|> string "/fc>" ) )
                  return [(s, c)]

-- | Wrapper for notFollowedBy that returns the result of the first parser.
--   Also works around the issue that, at least in Parsec 3.0.0, notFollowedBy
--   accepts only parsers with return type Char.
notFollowedBy' :: Parser a -> Parser b -> Parser a
notFollowedBy' p e = do x <- p
                        notFollowedBy (e >> return '*')
                        return x

-- | Parsers a string wrapped in a color specification.
colorParser :: Parser [(String, String)]
colorParser = do
  c <- between (string "<fc=") (string ">") colors
  s <- manyTill (textParser c <|> colorParser) (try $ string "</fc>")
  return (concat s)

-- | Parses a color specification (hex or named)
colors :: Parser String
colors = many1 (alphaNum <|> char ',' <|> char '#')

-- | Parses the output template string
templateStringParser :: Config -> Parser (String,String,String)
templateStringParser c = do
  s   <- allTillSep c
  com <- templateCommandParser c
  ss  <- allTillSep c
  return (com, s, ss)

-- | Parses the command part of the template string
templateCommandParser :: Config -> Parser String
templateCommandParser c =
  let chr = char . head . sepChar
  in  between (chr c) (chr c) (allTillSep c)

-- | Combines the template parsers
templateParser :: Config -> Parser [(String,String,String)]
templateParser = many . templateStringParser

-- | Actually runs the template parsers
parseTemplate :: Config -> String -> IO [(Runnable,String,String)]
parseTemplate c s =
    do str <- case parse (templateParser c) "" s of
                Left _  -> return [("","","")]
                Right x -> return x
       let cl = map alias (commands c)
           m  = Map.fromList $ zip cl (commands c)
       return $ combine c m str

-- | Given a finite "Map" and a parsed templatet produces the
-- | resulting output string.
combine :: Config -> Map.Map String Runnable -> [(String, String, String)] -> [(Runnable,String,String)]
combine _ _ [] = []
combine c m ((ts,s,ss):xs) = (com, s, ss) : combine c m xs
    where com  = Map.findWithDefault dflt ts m
          dflt = Run $ Com ts [] [] 10

allTillSep :: Config -> Parser String
allTillSep = many . noneOf . sepChar

instance Applicative (GenParser tok st) where
    pure = return
    (<*>) = ap

instance Alternative (GenParser tok st) where
    (<|>) x y = (Parsec.<|>) (try x) y
    empty = pzero

readsToParsec :: Read b => CharParser st b
readsToParsec = do
    pos0 <- getPosition
    input <- getInput
    case reads input of
        (result,rest):_ -> do
            sequenceA_ $ do
                  ls <- fmap (lines . fst) . find ((==rest) . snd)
                            $ zip (inits input) (tails input)
                  lastLine <- safeLast ls
                  return $ setPosition
                      . flip setSourceColumn (length lastLine)
                      . flip incSourceLine (length ls - 1) $ pos0
            setInput rest
            return result
        _ -> setInput input >> fail "readsToParsec failed"

safeLast :: [a] -> Maybe a
safeLast [] = Nothing
safeLast xs = Just (last xs)

liftM9 :: (Monad m) => (a1 -> a2 -> a3 -> a4 -> a5 -> a6 -> a7 -> a8 -> a9 -> b) ->
          m a1 -> m a2 -> m a3 -> m a4 -> m a5 -> m a6 -> m a7 -> m a8 -> m a9 -> m b
liftM9 fun a b c d e f g h i
    = fun `liftM` a `ap` b `ap` c `ap` d `ap` e `ap` f `ap` g `ap` h `ap` i

-- | Parse the config, logging a list of fields that were missing and replaced
-- by the default definition.
parseConfig :: MonadWriter [String] m => String -> Either ParseError (m Config)
parseConfig = flip parse "Config" $ sepEndSpaces ["Config","{"]
                                    *> perms <* wrapSkip (string "}") <* eof
    where
      perms = runPermsSep (wrapSkip $ string ",") $ liftM9 Config
        <$> withDef font         "font"          strField
        <*> withDef bgColor      "bgColor"       strField
        <*> withDef fgColor      "fgColor"       strField
        <*> withDef position     "position"     (field readsToParsec)
        <*> withDef lowerOnStart "lowerOnStart" (field parseEnum    )
        <*> withDef commands     "commands"     (field readsToParsec)
        <*> withDef sepChar      "sepChar"       strField
        <*> withDef alignSep     "alignSep"      strField
        <*> withDef template     "template"      strField

      wrapSkip x = many space *> x <* many space
      sepEndSpaces = mapM_ (\s -> string s <* many space)

      withDef ext name parser = optAtom (do tell [name]; return $ ext defaultConfig)
                                        (liftM return $ parser name)

      parseEnum = choice $ map (\x -> x <$ string (show x)) [minBound .. maxBound]

      strField name = flip field name $ between (char '"') (char '"') (many1 . satisfy $ (/= '"'))
      field cont name = sepEndSpaces [name,"="] *> cont