yi-0.5.0.1: Yi/Rectangle.hs

-- Copyright (C) 2008 JP Bernardy
module Yi.Rectangle where

import Yi.Prelude
import Prelude (subtract)
import Data.List (splitAt, unzip)
import Control.Applicative
import Data.Char
import Data.List (sort)

import Yi.Buffer
import Yi.Editor
import Yi.String

-- | Get the selected region as a rectangle.
-- Returns the region extended to lines, plus the start and end columns of the rectangle.
getRectangle :: BufferM (Region, Int, Int)
getRectangle = do
    r <- getSelectRegionB
    extR <- unitWiseRegion Line r
    [lowCol,highCol] <- sort <$> mapM colOf [regionStart r, regionEnd r]
    return (extR, lowCol, highCol)

multiSplit :: [Int] -> [a] -> [[a]]
multiSplit [] l = [l]
multiSplit (x:xs) l = left : multiSplit (fmap (subtract x) xs) right
    where (left,right) = splitAt x l

onRectangle :: (Int -> Int -> String -> String) -> BufferM ()
onRectangle f = do
    (reg, l, r) <- getRectangle 
    modifyRegionB (mapLines (f l r)) reg

openRectangle :: BufferM ()
openRectangle = onRectangle openLine
    where openLine l r line = left ++ replicate (r-l) ' ' ++ right
              where (left,right) = splitAt l line

stringRectangle :: String -> BufferM ()
stringRectangle inserted = onRectangle stringLine
    where stringLine l r line = left ++ inserted ++ right
              where [left,_,right] = multiSplit [l,r] line

killRectangle :: EditorM ()
killRectangle = do
    cutted <- withBuffer0 $ do
        (reg, l, r) <- getRectangle
        text <- readRegionB reg
        let (cutted, rest) = unzip $ fmap cut $ lines' text
            cut line = let [left,mid,right] = multiSplit [l,r] line in (mid, left ++ right)
        replaceRegionB reg (unlines' rest)
        return cutted
    setRegE (unlines' cutted)

yankRectangle :: EditorM ()
yankRectangle = do
    text <- lines' <$> getRegE
    withBuffer0 $ do
        forM_ text $ \t -> do
            savingPointB $ insertN t
            lineDown