summaryrefslogtreecommitdiffstats
path: root/src/Blessings.hs
blob: 56c1af0c3f809737630bc4f605f450d1ddbbff49 (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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE RecordWildCards #-}

module Blessings where

import Control.Applicative
import Data.List
import Data.String
import Data.Ix (inRange)

type Ps = Int
type Pm = [Ps]

data Blessings a
    = Plain a
    | SGR Pm (Blessings a)
    | Append (Blessings a) (Blessings a)
    | Empty
  deriving (Eq, Show)


instance Foldable Blessings where
    foldMap f = \case
        Append t1 t2 -> foldMap f t1 <> foldMap f t2
        Plain s -> f s
        SGR _ t -> foldMap f t
        Empty -> mempty


instance Functor Blessings where
    fmap f = \case
        Append t1 t2 -> Append (fmap f t1) (fmap f t2)
        Plain s -> Plain (f s)
        SGR pm t -> SGR pm (fmap f t)
        Empty -> Empty


instance Semigroup (Blessings a) where
    t <> Empty = t
    Empty <> t = t
    Append t1 t2 <> Append t3 t4 = t1 <> t2 <> t3 <> t4
    Append t1 t2 <> t3 = t1 <> t2 <> t3
    t1 <> t2 = Append t1 t2


instance Monoid (Blessings a) where
    mempty = Empty


instance IsString a => IsString (Blessings a) where
    fromString = Plain . fromString


class IsPm a where
    toPm :: a -> Pm
    fromPm :: Pm -> Maybe a


data FColor = ECMA48FColor Ps   -- ECMA-48 / ISO 6429 / ANSI X3.64
            | Xterm256FColor Ps
            | ISO8613_3FColor Ps Ps Ps
  deriving (Eq, Show)

instance IsPm FColor where
    toPm (ECMA48FColor i) = [i]
    toPm (Xterm256FColor i) = [38,5,i]
    toPm (ISO8613_3FColor r g b) = [38,2,r,g,b]
    fromPm = fromSGRPm SGRPm
               { def8Ps = 39
               , extPs = 38
               , lo8Ps = 30
               , hi8Ps = 37
               , makeECMA48Color = ECMA48FColor
               , makeXterm256Color = Xterm256FColor
               , makeISO8613_3Color = ISO8613_3FColor
               }
           . filterPm sgrBColor


data BColor = ECMA48BColor Ps
            | Xterm256BColor Ps
            | ISO8613_3BColor Ps Ps Ps
  deriving (Eq, Show)


instance IsPm BColor where
    toPm (ECMA48BColor i) = [i]
    toPm (Xterm256BColor i) = [48,5,i]
    toPm (ISO8613_3BColor r g b) = [48,2,r,g,b]
    fromPm = fromSGRPm SGRPm
                 { def8Ps = 49
                 , extPs = 48
                 , lo8Ps = 40
                 , hi8Ps = 47
                 , makeECMA48Color = ECMA48BColor
                 , makeXterm256Color = Xterm256BColor
                 , makeISO8613_3Color = ISO8613_3BColor
               }
           . filterPm sgrFColor


data Blink = Blink | NoBlink
  deriving (Eq, Show)

instance IsPm Blink where
    toPm Blink = [5]
    toPm NoBlink = [25]
    fromPm = rec . filterPm sgrColor
      where
        rec xs = case filter (`elem` ([5,25] :: [Int])) xs of
            [] -> Nothing
            xs' -> case last xs' of
                5 -> Just Blink
                25 -> Just NoBlink
                _ -> error "filter broken in fromPm :: Pm -> Maybe Blink"


data Bold = Bold | NoBold
  deriving (Eq, Show)

instance IsPm Bold where
    toPm Bold = [1]
    toPm NoBold = [22]
    fromPm = rec . filterPm sgrColor
      where
        rec xs = case filter (`elem` ([1,22] :: [Int])) xs of
            [] -> Nothing
            xs' -> case last xs' of
                1 -> Just Bold
                22 -> Just NoBold
                _ -> error "filter broken in fromPm :: Pm -> Maybe Bold"


data Underline = Underline | NoUnderline
  deriving (Eq, Show)

instance IsPm Underline where
    toPm Underline = [4]
    toPm NoUnderline = [24]
    fromPm = rec . filterPm sgrColor
      where
        rec xs = case filter (`elem` ([4,24] :: [Int])) xs of
            [] -> Nothing
            xs' -> case last xs' of
                1 -> Just Underline
                22 -> Just NoUnderline
                _ -> error "filter broken in fromPm :: Pm -> Maybe Underline"


data SGRPm c = SGRPm
    { def8Ps :: Ps
    , extPs :: Ps
    , lo8Ps :: Ps
    , hi8Ps :: Ps
    , makeECMA48Color :: Ps -> c
    , makeXterm256Color :: Ps -> c
    , makeISO8613_3Color :: Ps -> Ps -> Ps -> c
    }


fromSGRPm :: IsPm c => SGRPm c -> Pm -> Maybe c
fromSGRPm SGRPm{..} = rec Nothing
  where
    rec mb_c (x:xs)
        | x == extPs = case xs of
            (2:r:g:b:xs') -> rec (Just $ makeISO8613_3Color r g b) xs'
            (5:i:xs')     -> rec (Just $ makeXterm256Color i) xs'
            _             -> rec mb_c xs
        | x == def8Ps = rec (Just $ makeECMA48Color def8Ps) xs
        | inRange (lo8Ps, hi8Ps) x = rec (Just $ makeECMA48Color x) xs
        | otherwise = rec mb_c xs
    rec mb_c _ = mb_c


-- filterPm is used to preprocess Pm before searching with fromPm in
-- order to remove (longer) sequences that could contain subsequences
-- that look like the (shorter) sequences we're searching.
-- E.g. we could find [1] (bold) in any extended color sequence.
-- TODO Can we combine this whole from*Pm with Scanner?
filterPm :: (Pm -> Maybe Int) -> Pm -> Pm
filterPm f = rec []
  where
    rec ys xs@(xhead:xtail) = maybe (rec (ys ++ [xhead]) xtail)
                                    (rec ys . flip drop xs)
                                    (f xs)
    rec ys _ = ys

sgrColor, sgrFColor, sgrBColor :: Pm -> Maybe Int

sgrColor xs = sgrFColor xs <|> sgrBColor xs

sgrFColor (38:5:_) = Just 3
sgrFColor (38:2:_) = Just 5
sgrFColor _ = Nothing

sgrBColor (48:5:_) = Just 3
sgrBColor (48:2:_) = Just 5
sgrBColor _ = Nothing


type RenderState = [(FColor, BColor, Blink, Bold, Underline)]


emptyRenderState :: RenderState
emptyRenderState = [(ECMA48FColor 39, ECMA48BColor 49, NoBlink, NoBold, NoUnderline)]

renderString :: RenderState -> Blessings String -> String -> String

renderString _ (Plain s) y = s ++ y

-- TODO merge successive sequences: \ESC[32m\ESC[1m -> \ESC[31;1m
renderString rs@((fc, bc, bl, b, u):_) (SGR c t) y =
    renderSGR bra ++ renderString rs' t (renderSGR ket ++ y)
  where
    fc' = maybe fc id $ fromPm c
    bc' = maybe bc id $ fromPm c
    bl' = maybe bl id $ fromPm c
    b'  = maybe  b id $ fromPm c
    u'  = maybe  u id $ fromPm c
    rs' = (fc', bc', bl', b', u') : rs
    bra = braket >>= fst
    ket = braket >>= snd
    braket =
        (if fc' /= fc then (toPm fc', toPm fc) else ([],[])) :
        (if bc' /= bc then (toPm bc', toPm bc) else ([],[])) :
        (if bl' /= bl then (toPm bl', toPm bl) else ([],[])) :
        (if b'  /=  b then (toPm  b', toPm  b) else ([],[])) :
        (if u'  /=  u then (toPm  u', toPm  u) else ([],[])) : []

renderString _ (SGR _ _) _ =
    error "renderString called w/o proper initial state"
    -- where a proper initial state is s.th. like emptyRenderState

renderString r (Append t1 t2) y =
    renderString r t1 $ renderString r t2 y

renderString _ Empty y = y


len :: Blessings String -> Int
len (Plain x) = length x
len (SGR _ x) = len x
len (Append t1 t2) = len t1 + len t2
len Empty = 0


pp :: Blessings String -> String
pp t = renderString emptyRenderState t ""


renderSGR :: Pm -> String
renderSGR [] = []
renderSGR xs = ("\ESC["++) . (++"m") . intercalate ";" $ map show xs


blessingsDrop :: Int -> Blessings String -> Blessings String
blessingsDrop n = \case
    Append t1 t2 ->
        case compare n (len t1) of
            LT -> Append (blessingsDrop n t1) t2
            EQ -> t2
            GT -> blessingsDrop (n - len t1) t2
    Plain s ->
        Plain (drop n s)
    SGR pm t ->
        SGR pm (blessingsDrop n t)
    Empty ->
        Empty


blessingsTake :: Int -> Blessings String -> Blessings String
blessingsTake n = \case
    Append t1 t2 ->
        case compare n (len t1) of
            LT -> blessingsTake n t1
            EQ -> t1
            GT -> Append t1 (blessingsTake (n - len t1) t2)
    Plain s ->
        Plain (take n s)
    SGR pm t ->
        SGR pm (blessingsTake n t)
    Empty ->
        Empty