[Tinyos-help] (yet another) Question about signal

[Michael Schippling]

Yes that makes a lost of sense, logically. It just seems odd, to me,
to have a bunch of redundant keywords cluttering up my code when the
intent is (almost?) always implicit in the usage...

Now, if "signal" actually fired off code in a different interrupt-like
context...that would be both logical and reasonable.

thx
MS

Jeongyeup Paek wrote:
> 
> I see 'call' and 'signal' as a type-checking mechanism with 'noop',
> where 'command' and 'event' can be regarded as
> 'INPUT' and 'OUTPUT' tags is VHDL language.
> Type checking (and a word of memo for the programmer)
> helps you to use INPUT and OUTPUT properly.
> They tell you the 'direction' in which you should call a function.
> 
> In fact, although some people say 'nesC is dialect of 'C' with
> notoriously strange add-ons such as command/event/component/modules,
> I see it more close to VHDL, with the internals written in C.
> You must wire an input pin with an output pin, and vice versa,
> for an interface between components. You must output a value on
> an output pin, and you must read a value on an input pin.
> Thus, compile-time type-checking mechanisms such as
> 'call' & 'signal' are very useful.
> 
> And... 'async' is just another type-checking,
> that let's you distinguish sequences of function calls
> that came/didn't come from a hardware interrupt.
> 
> This is how I understood it through couple years of playing around..
> 
> Thanks
> 
> - jpaek
> 
> 
> Michael Schippling wrote:
>> OK, so I found
>>     nesC 1.1 Language Reference Manual (2003)
>> and
>>     The nesC Language:... (2003)
>>
>> but in a quick search I don't find _what_ is the meaning of "signal",
>> except that it seems to be prefixed to calling functions labeled "event".
>> Do I need to really read the whole thing to get the idea, or is there
>> some summary that explains the hierarchy and impetus behind these 
>> keywords?
>> Or do I have to re-remember BNF?
>>
>> thx
>> MS
>>
>> Philip Levis wrote:
>>>
>>> On Nov 14, 2007, at 10:05 AM, Michael Schippling wrote:
>>>
>>>> I guess if I took the time to read and understand all the NESCC 
>>>> design/doc,
>>>> rather than wasting it on trying to make my own projects work, I 
>>>> wouldn't
>>>> be asking so many seemingly redundant questions. I expect the whole 
>>>> thing
>>>> has to do with using "async" as a flag to force race-condition 
>>>> evaluation,
>>>> which then blossomed into a chain of fix-the-boundary-cases keywords.
>>>
>>> Not at all. The async keyword wasn't introduced until TinyOS 1.1.
>>>
>>> Phil
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