parser.erl

% Simple erlang parser.

-module(parser).
-compile([export_all]).

% Start char, with start State
-define(DATA_START(X, K),
	data(<<X, Rest/bitstring>>, Buf, Ret) ->
	       data(Rest, Buf, Ret, K)).

% End char, drop the rest of the line
-define(DATA_END(X),
	data(<<X>>, Buf, Ret, State) ->
	       Ret ++ [{State, Buf}];
	    data(<<X,_/bitstring>>, Buf, Ret, State) ->
	       [{State, Buf}] ++ Ret).

% Null char, just dropped.
-define(DATA_NULL(X), 
	data(<<X, Rest/bitstring>>, Buf, Ret, State) ->
	       data(Rest, Buf, Ret, State)).

% Character(s), Current State, Next State
-define(DATA_SEP(X, S, N),
	data(<<X, Rest/bitstring>>, Buf, Ret, S) ->
	       data(Rest, <<>>, [{S, Buf}] ++ Ret , N)).

data(Bitstring) ->
    data(Bitstring, <<>>, []).

?DATA_START("[", key).

?DATA_END("]");
?DATA_NULL(" ");
?DATA_SEP(":", key, value);
?DATA_SEP("->", value, target);
?DATA_SEP("<-", target, from);
data(<<Char, Rest/bitstring>>, Buf, Ret, State) 
  when (Char >= $0 andalso Char =< $9 ) orelse
       (Char >= $A andalso Char =< $z ) ->
    data(Rest, <<Buf/bitstring, Char>>, Ret, State);
data(<<Char, Rest/bitstring>>, _, _, State) ->
    {error, bad_char, <<Char>>, State}.