ghcup-hs/lib/GHCup/Prelude/Ansi.hs
2023-01-05 21:41:01 +08:00

93 lines
3.3 KiB
Haskell

module GHCup.Prelude.Ansi where
import Control.Applicative
import Data.Char
import Data.Void
import qualified Text.Megaparsec as MP
import qualified Text.Megaparsec.Char as MPC
-- | Calculate the render width of a string, considering
-- wide characters (counted as double width), ANSI escape codes
-- (not counted), and line breaks (in a multi-line string, the longest
-- line determines the width).
strWidth :: String -> Int
strWidth =
maximum
. (0 :)
. map (foldr (\a b -> charWidth a + b) 0)
. lines
. stripAnsi
-- | Strip ANSI escape sequences from a string.
--
-- >>> stripAnsi "\ESC[31m-1\ESC[m"
-- "-1"
stripAnsi :: String -> String
stripAnsi s' =
case
MP.parseMaybe (many $ "" <$ MP.try ansi <|> pure <$> MP.anySingle) s'
of
Nothing -> error "Bad ansi escape" -- PARTIAL: should not happen
Just xs -> concat xs
where
-- This parses lots of invalid ANSI escape codes, but that should be fine
ansi =
MPC.string "\ESC[" *> digitSemicolons *> suffix MP.<?> "ansi" :: MP.Parsec
Void
String
Char
digitSemicolons = MP.takeWhileP Nothing (\c -> isDigit c || c == ';')
suffix = MP.oneOf ['A', 'B', 'C', 'D', 'H', 'J', 'K', 'f', 'm', 's', 'u']
-- | Get the designated render width of a character: 0 for a combining
-- character, 1 for a regular character, 2 for a wide character.
-- (Wide characters are rendered as exactly double width in apps and
-- fonts that support it.) (From Pandoc.)
charWidth :: Char -> Int
charWidth c = case c of
_ | c < '\x0300' -> 1
| c >= '\x0300' && c <= '\x036F' -> 0
| -- combining
c >= '\x0370' && c <= '\x10FC' -> 1
| c >= '\x1100' && c <= '\x115F' -> 2
| c >= '\x1160' && c <= '\x11A2' -> 1
| c >= '\x11A3' && c <= '\x11A7' -> 2
| c >= '\x11A8' && c <= '\x11F9' -> 1
| c >= '\x11FA' && c <= '\x11FF' -> 2
| c >= '\x1200' && c <= '\x2328' -> 1
| c >= '\x2329' && c <= '\x232A' -> 2
| c >= '\x232B' && c <= '\x2E31' -> 1
| c >= '\x2E80' && c <= '\x303E' -> 2
| c == '\x303F' -> 1
| c >= '\x3041' && c <= '\x3247' -> 2
| c >= '\x3248' && c <= '\x324F' -> 1
| -- ambiguous
c >= '\x3250' && c <= '\x4DBF' -> 2
| c >= '\x4DC0' && c <= '\x4DFF' -> 1
| c >= '\x4E00' && c <= '\xA4C6' -> 2
| c >= '\xA4D0' && c <= '\xA95F' -> 1
| c >= '\xA960' && c <= '\xA97C' -> 2
| c >= '\xA980' && c <= '\xABF9' -> 1
| c >= '\xAC00' && c <= '\xD7FB' -> 2
| c >= '\xD800' && c <= '\xDFFF' -> 1
| c >= '\xE000' && c <= '\xF8FF' -> 1
| -- ambiguous
c >= '\xF900' && c <= '\xFAFF' -> 2
| c >= '\xFB00' && c <= '\xFDFD' -> 1
| c >= '\xFE00' && c <= '\xFE0F' -> 1
| -- ambiguous
c >= '\xFE10' && c <= '\xFE19' -> 2
| c >= '\xFE20' && c <= '\xFE26' -> 1
| c >= '\xFE30' && c <= '\xFE6B' -> 2
| c >= '\xFE70' && c <= '\xFEFF' -> 1
| c >= '\xFF01' && c <= '\xFF60' -> 2
| c >= '\xFF61' && c <= '\x16A38' -> 1
| c >= '\x1B000' && c <= '\x1B001' -> 2
| c >= '\x1D000' && c <= '\x1F1FF' -> 1
| c >= '\x1F200' && c <= '\x1F251' -> 2
| c >= '\x1F300' && c <= '\x1F773' -> 1
| c >= '\x20000' && c <= '\x3FFFD' -> 2
| otherwise -> 1