calopez · April 5, 2017 02:43 · Apr 5, 2017 · Apr 5, 2017 · Apr 3, 2017
diff --git a/palin.erl b/palin.erl
@@ -109,7 +109,7 @@ response(String) ->
     Be = if Is =:= true -> " is ";
             true -> " is not "
          end,
-    {result, lists:flatten(["\"", String, "\"", Be, "palindrome"])}.
+    {result, lists:flatten([$", String, $", Be, "palindrome"])}.
 
 
 %% ------

diff --git a/palin.erl b/palin.erl
@@ -70,20 +70,48 @@ client() ->
 %% Server
 %% -------
 server() ->
+    Workers = palin_workers(),
     receive
-        {check, Pid, String} ->
-            Pid ! response(String),
+        {check, Client, Payload} ->
+            lb(Workers, Client, Payload),
             server();
         stop -> io:format("stopped ~n")
     end.
 
+
+lb(Workers, Client, Payload) when is_pid(Client) ->
+    Worker = element(rand:uniform(2), Workers),
+    Worker ! {Client, Payload}.
+
+palin_workers() ->
+    {
+      spawn(fun worker1/0),
+      spawn(fun worker2/0)
+    }.
+
+
+worker1() ->
+    receive
+        {Client, Payload} ->
+            io:format("response from Sever 1!~n"),
+            Client ! response(Payload)
+    end.
+
+worker2() ->
+    receive
+        {Client, Payload} ->
+            io:format("response from Sever 2!~n"),
+            Client ! response(Payload)
+    end.
+
 response(String) ->
     Is = palindrome(String),
     Be = if Is =:= true -> " is ";
-                   true -> " is not "
+            true -> " is not "
          end,
     {result, lists:flatten(["\"", String, "\"", Be, "palindrome"])}.
 
+
 %% ------
 %% Usage
 %% ------

diff --git a/palin.erl b/palin.erl
@@ -0,0 +1,94 @@
+-module(palin).
+-export([
+         palin/1,
+         nopunct/1,
+         palindrome/1,
+         client/0,
+         server/0
+]).
+
+% palindrome problem
+%
+% palindrome("Madam I\'m Adam.") = true
+
+palindrome(Xs) ->
+    palin(nocaps(nopunct(Xs))).
+
+nopunct([]) ->
+    [];
+nopunct([X|Xs]) ->
+    case lists:member(X,".,\ ;:\t\n\'\"") of
+	true ->
+	    nopunct(Xs);
+	false ->
+	    [ X | nopunct(Xs) ]
+    end.
+
+nocaps([]) ->
+    [];
+nocaps([X|Xs]) ->
+    [ nocap(X) | nocaps(Xs) ].
+
+nocap(X) ->
+    case $A =< X andalso X =< $Z of
+	true ->
+	    X+32;
+	false ->
+	    X
+    end.
+
+% literal palindrome
+
+palin(Xs) ->
+    Xs == reverse(Xs).
+
+reverse(Xs) ->
+    shunt(Xs,[]).
+
+shunt([],Ys) ->
+    Ys;
+shunt([X|Xs],Ys) ->
+    shunt(Xs,[X|Ys]).
+
+%% -------
+%% Client
+%% -------
+
+client() ->
+    receive
+        {send, Pid, Msg} ->
+            Pid ! Msg;
+        {result, Msg } ->
+            io:format("client received: ~p~n", [Msg]),
+            client();
+        stop ->
+            io:format("client stopped!")
+    end.
+
+
+%% -------
+%% Server
+%% -------
+server() ->
+    receive
+        {check, Pid, String} ->
+            Pid ! response(String),
+            server();
+        stop -> io:format("stopped ~n")
+    end.
+
+response(String) ->
+    Is = palindrome(String),
+    Be = if Is =:= true -> " is ";
+                   true -> " is not "
+         end,
+    {result, lists:flatten(["\"", String, "\"", Be, "palindrome"])}.
+
+%% ------
+%% Usage
+%% ------
+%% 1> Server = spawn(palin, server, []).
+%% 2> Client = spawn(palin, client, []).
+%% 3> Server ! {check, Client, "Air an aria"}.
+%% 4> Server ! {check, self(), "Air an aria"}.
+%% 5> flush().
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