a215.erl

%%% assignment 2.15 palindromes

-module(a215).
-include_lib("eunit/include/eunit.hrl").
-created_by("Marcelo Ruiz Camauër").

-export([palindrome/1]).
-export([remove_punctuation/2]).

-spec palindrome(list()) -> boolean().
palindrome([])->false;

palindrome(L)->
    M=remove_punctuation(L,[]),
    N=lists:reverse(M),
    N==M.


%% helper functions. Inspired/copied from Hynek Vychodil
remove_punctuation([],Normalized)->
    Normalized;

remove_punctuation([H|T],Normalized) when H>= $a, H=< $z ->
    remove_punctuation(T,[H|Normalized]);

remove_punctuation([H|T],Normalized) when H>= $A, H=< $Z ->
    remove_punctuation(T,[H+32|Normalized]);

remove_punctuation([_|T],Normalized) ->
%   io:format("remove_punctuation ~s ~n",[T]),
    remove_punctuation(T,Normalized).




%%%%%%%%%%%%%%%
% invoke with 'a215:test().' or "eunit:test(a215)."
palindrome_test_()->
    [   ?_assert(palindrome("A man, a plan, a canal: Panama!")==true),
        ?_assert(palindrome("Able was I ere I saw Elba")==true),
        ?_assert(palindrome("Madam, I'm Adam")==true),
        ?_assert(palindrome("Never odd or even")==true),
        ?_assert(palindrome("Doc, note: I dissent. A fast never prevents a fatness.
                      I diet on cod")==true),
        ?_assert(palindrome("T. Eliot, top bard, notes putrid tang emanating, is
                      sad; I'd assign it a name: gnat dirt upset on drab pot
                      toilet.")==true),
        ?_assert(palindrome([])==false),
        ?_assert(palindrome("A man, no plan, bad canal: Panama")==false)
    ].