% the technology of faucets
declare
fun {MakeFaucet Filename Stream}
   F={New Open.file init(name:Filename flags: [write create])} in
   F#{NewCell true}#Stream
end

proc {TurnOffFaucet F#OK#_}
   OK := false
   {F close}
end

proc {TeeFaucet F#OK#Stream VSifier}
   if @OK
   then case Stream of
	   X|Xs then {F write(vs:{VSifier X})} {TeeFaucet F#OK#Xs VSifier}
	[] nil then skip
	end
   else skip
   end
end


%% EXAMPLE
% make your own
% declare MyStream Portal
% {NewPort MyStream Portal}
% PricePfister={MakeFaucet 'pricepfister.txt' MyStream}

% run these commands
% thread {TeeFaucet PricePfister} end
% {Send Portal 'howdy\n'}
% {Send Portal 'another friendly message\n'}
% {TurnOffFaucet PricePfister}