Couchdb: An erlang map function to get a value from a sub record

erlang_couchdb_map.erl

% Couchdb: An erlang map function to get a value from a sub record
% 
% gets and emits a record for each sub record in legs keyed by "value_date"
% For the date see: https://gist.github.com/1125467 
%
fun({Doc}) ->
	Bump = fun(Doc, Rec, Field) ->
		case {proplists:get_value(Field, Rec)} of
             		{undefined} ->
                      		ok;
                 	{Key} ->
				proplists:expand(Rec, Doc),
                     		Emit(Key, {Rec})
                   	 end
		end,

		Legs = proplists:get_value(<<"legs">>, Doc),
                XX = [Bump(Doc, X, <<"value_date">>) || {X} <- Legs]
                end.