<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>All,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>I’m working on an optical archiving application. I wrote a NIF wrapper around a burning SDK. Other relevant parts are a task queue, which holds burning or reading tasks, and a web based gui which shows the drives’ state to the user. In the middle sits an Erlang module controlling a physical drive, and of cause the application should handle multiple drives.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>Because the drives’ state diagram is fairly complex (reading, burning, handling different media capacities and types, hw events, errors, user interactions on GUI or pressing the eject button, etc.) I started to implement it as a gen_fsm.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>Now, my problem: most of the events triggering a state change are coming in plain Erlang messages (from the NIF, or from gproc what I use to connect to the GUI module). I can capture these events with handle_info but I lose the major advantage of the gen_fsm. If two subsequent events are coming through handle_info, I vainly specify the new state, because the state’s callback won’t be ever reached. My code is a bunch of handle_infos and they are just handling the specific events in any state.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>What is an advisabel practice to code such an FSM?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>Thanks for any ideas in advance.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>Janos<o:p></o:p></span></p></div></body></html>