{- Copyright (C) 2016 Dr. Alistair Ward This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. -} {- | [@AUTHOR@] Dr. Alistair Ward [@DESCRIPTION@] Miscellaneous String-orientated functions. -} module ToolShed.Data.String( -- * Functions deTab ) where -- | Replaces any embedded tab-characters with the appropriate number of spaces. deTab :: Int -- ^ Tab-length. -> String -> String deTab tabLength | tabLength < 0 = error . showString "ToolShed.Data.String.deTab:\ttab-length=" $ shows tabLength " must be negative." | tabLength == 0 = filter (/= '\t') | otherwise = slave 0 where slave :: Int -> String -> String slave _ [] = [] -- Terminate. slave i (c : s) = case c of '\t' -> replicate (tabLength - mod i tabLength) ' ' ++ slave 0 s '\r' -> c : slave 0 s '\n' -> c : slave 0 s _ -> c : slave (succ i) s