% Copyright (C) 2008 Eric Kow
%
% 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 2, 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; see the file COPYING. If not, write to
% the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
% Boston, MA 02110-1301, USA.
\begin{code}
module English where
englishNum :: Numbered n => Int -> n -> ShowS
englishNum x = if x == 1 then singular else plural
class Numbered a where
plural :: a -> ShowS
singular :: a -> ShowS
newtype Noun = Noun String
instance Numbered Noun where
plural (Noun "") = id
-- note that this is wrong! consider 'cat-es' and 'dog-es'
-- but it works for darcs 'patch-es' and 'change-s'
plural (Noun s) | last s == 'e' = showString s . showChar 's'
plural (Noun s) = showString s . showString "es"
singular (Noun s) = showString s
data This = This Noun
instance Numbered This where
plural (This s) = showString "these " . plural s
singular (This s) = showString "this " . singular s
\end{code}