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module Hack.Buffer.Motion where
import Data.List (dropWhileEnd)
import Hack.Buffer.Class
-- TODO factor Count
-- TODO various Vim gX
data Motion
= CharsBackward
| CharsForward
| ToStartOfLine
-- | GotoFirstNonBlankChar
| ToEndOfLine -- XXX in Vi this can go downwards
| ToColumn
-- | GotoFindLeft (Char -> Bool) -- TODO don't use functions here
-- | GotoFindRight (Char -> Bool) -- TODO ^ dto.
-- | GotillFindLeft Char
-- | GotillFindRight Char
-- | RepeatLastFind
-- | RepeatLastFindReverse
| WordsForward
| WordsBackward
deriving (Show)
-- TODO fail if cannot splitAt properly OR if we didn't modify the buffer
gotoLeft :: Int -> Buffer -> Buffer
gotoLeft i (ls, rs) =
let (lls, rls) = splitAt (length ls - i) ls in (lls, rls ++ rs)
-- TODO fail if cannot splitAt properly OR if we didn't modify the buffer
gotoRight :: Int -> Buffer -> Buffer
gotoRight i (ls, rs) =
let (lrs, rrs) = splitAt i rs in (ls ++ lrs, rrs)
gotoFirstChar :: Buffer -> Buffer
gotoFirstChar (ls, rs) = ("", ls ++ rs)
gotoEndOfLine :: Buffer -> Buffer
gotoEndOfLine (ls, rs) = (ls ++ rs, "")
-- TODO fail if i <= 0 or i > length
gotoColumn :: Int -> Buffer -> Buffer
gotoColumn i (ls, rs) = splitAt (i - 1) $ ls ++ rs
wordsForward :: Int -> Buffer -> Buffer
wordsForward i (ls, rs) =
let rs' = dropWhile (==' ') $ dropWhile (/=' ') rs
ls' = ls ++ take (length rs - length rs') rs
b' = (ls', rs')
in
if i > 1
then wordsForward (i - 1) b'
else b'
wordsBackward :: Int -> Buffer -> Buffer
wordsBackward i (ls, rs) =
let ls' = dropWhileEnd (/=' ') $ dropWhileEnd (==' ') ls
rs' = drop (length ls') ls ++ rs
b' = (ls', rs')
in
if i > 1
then wordsBackward (i - 1) b'
else b'
move :: Motion -> Int -> Buffer -> Buffer
move CharsBackward c = gotoLeft c
move CharsForward c = gotoRight c
move ToStartOfLine _ = gotoFirstChar -- TODO use count
move ToEndOfLine _ = gotoEndOfLine -- TODO use count
move ToColumn c = gotoColumn c
move WordsForward c = wordsForward c
move WordsBackward c = wordsBackward c
select :: Motion -> Int -> Buffer -> String
select x i b =
if nls' < nls then take (nls - nls') rs' else
if nrs' < nrs then take (nrs - nrs') rs else
""
where
(ls, rs) = b
(ls', rs') = move x i b
nls = length ls
nls' = length ls'
nrs = length rs
nrs' = length rs'
delete :: Motion -> Int -> Buffer -> Buffer
delete x i b =
( if nls' < nls then ls' else ls
, if nrs' < nrs then rs' else rs
)
where
(ls, rs) = b
(ls', rs')= move x i b
nls = length ls
nls' = length ls'
nrs = length rs
nrs' = length rs'
|
