Alias.hs

   1 -- This file is part of Diohsc
   2 -- Copyright (C) 2020 Martin Bays <mbays@sdf.org>
   3 --
   4 -- This program is free software: you can redistribute it and/or modify
   5 -- it under the terms of version 3 of the GNU General Public License as
   6 -- published by the Free Software Foundation, or any later version.
   7 --
   8 -- You should have received a copy of the GNU General Public License
   9 -- along with this program.  If not, see http://www.gnu.org/licenses/.
  10
  11 {-# LANGUAGE Safe #-}
  12
  13 module Alias where
  14
  15 import           Data.Bifunctor (second)
  16 import           Data.List      (isPrefixOf)
  17 import           Safe           (headMay)
  18
  19 import           CommandLine
  20
  21 data Alias = Alias String CommandLine
  22     deriving (Eq,Ord,Show)
  23
  24 type Aliases = [(String,Alias)]
  25
  26 emptyAliases :: Aliases
  27 emptyAliases = []
  28
  29 defaultAliases :: Aliases
  30 defaultAliases = second aliasOf <$>
  31     [ ("back", "<") , ("forward", ">") , ("next", "~") ]
  32     where aliasOf s = case parseCommandLine s of
  33             Right cl -> Alias s cl
  34             Left _   -> error "BUG: Failed to parse command for default alias."
  35
  36 lookupAlias :: String -> Aliases -> Maybe Alias
  37 lookupAlias s aliases =
  38     headMay [ alias | (a,alias) <- aliases, s `isPrefixOf` a ]
  39
  40 insertAlias :: String -> Alias -> Aliases -> Aliases
  41 insertAlias a alias = (++ [(a, alias)])
  42
  43 deleteAlias :: String -> Aliases -> Aliases
  44 deleteAlias a = filter $ (/= a) . fst