The last time I looked at HAL, it was limited to a very short command line. If it were possible to supply it with more information, we could build some truly generic HAL components.
Four decades ago, when I worked at Bristol Division of ACCO (later Bristol Babcock), I built a HAL-like system. It had similar components -- a PID component, a filter component, a logic component, an arithmetic component. The difference is that the logic component and arithmetic component had (virtually) unlimited inputs and outputs. The configurations for those components let you "say" things like: (For the arithmetic component) offset = range/2 gain = 2 * (basis + offset) (or for the logic component) toggle = toggle ^ 1 enable = toggle & (divot | quit) Variables were all global and defined by configuring a symbol table. Variables were "looked up" when the component was loaded and converted to a simple byte code. Execution of statements involved interpretation of the byte code in real time. Four "priorities" were supported which correspond to the "thread" supported by HAL. This was all done on an Intel 8080 processor, with the code written in assembly language. I believe that the maximum memory of that processor was 64K. --------------- These systems were intended to be used to control everything from pipeline compressors, to refineries, to dog food mixers. I believe that a similar functionality would provide the "scripting" capabilities that some people are requesting. I would consider combining logic and arithmetic functions into the same component. Thoughts, comments, ideas? Regards, Ken On 8/12/2012 6:06 AM, Les Newell wrote: > While comp is pretty easy to use it does take quite a lot of work to set > up the environment for building components. I think scripting would be a > useful addition and Lua is a very good choice. It is one of the fastest > of the common scripting languages and it has relatively low memory > requirements. > > Implementing a Lua HAL module should be relatively simple. It is just a > case of building the interface between Lua and HAL. Lua is designed to > be easy to extend so the interface would not be a major problem. > Scripting would just be another HAL module with no need for any changes > to HAL itself. > > Les > > >> Alex, I'm trying to follow you, but I don't understand your goal. (And I >> went back and read several of your messages.) >> >> Why do you think that adding a scripting language like Lua to the hal layer >> would be desirable? Hal is pretty simple in it's implementation. >> >> I doubt that adding a scripting language to hal is going to help hobbyists. >> And I suspect that Lua would be too slow for the Hal layer. >> >> Have you tried Comp? It works very well if you want to create your own real >> time component. C is a pretty simple language compared to just about >> anything else. >> >> Dave >> > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Emc-developers mailing list > Emc-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
