Re: parser for embedded systems
- From: chrisu <chrisu@xxxxxxxxxxxxxxxxxxxx>
- Date: Sun, 18 Jan 2009 12:15:51 +0100
hello,
my requirements are:
- code footsprint up to 50k
- ram usage. in the optimal case nearly nothing. but 5k is no problem.
- modify or expand the parser without any coding - just by changing some configure and maybe generating some new code
i need to implement an ethernet terminal on an embedded system to execute simple code (hopefully no loops or conditions) and mainly call functions from my application to configure and get some statistics in runtime. this is all i'm looking for;) tinypy, lua or flex and bison ... is too mighty for my purpose - but re2c seems be be the right choice.
thanks for your helpful suggestions!
chrisu
Jon Kirwan wrote:
On Sat, 17 Jan 2009 15:00:58 +0100, chrisu.
<chrisu@xxxxxxxxxxxxxxxxxxxx> wrote:
i need to use a parser in my embedded software. currently i am trying to integrate tinypy or lua. has anyone experience using parsers in embedded software. the requirements for the parser are the following:
- easy to integrate in a c application, no c++
- small footprint, some kbytes in flash and ram
- fast
- execute functions from firmware with parser
- command line interface, read variables ...
please give me some hints...
Okay. Are you looking for the ability to permit customers to execute
code they write as a custom matter? Or do you just want them to be
able to examine internal states, change control parameters, dump them
out, and so on?
If you intend supporting a language of sorts, why? What purpose is
being served here? For example, can you accept a mechanism like BASIC
'gosub/return' with global variables? Or do you have to have concepts
like local variables, passed parameters, and so on? Also, what exact
access is needed into the rest of your embedded application?
What precisely is your flash and RAM limits? I'm asking this because
tinypy is "a minimalist implementation of python in 64k of code" and
that makes me wonder what you mean by "some kbytes." Worse, lua is
said that "under Linux, the Lua interpreter built with all standard
Lua libraries takes 153K and the Lua library takes 203K" and that is
with Linux sitting there for some support functions, as well! So what
in the heck do you mean? Are we talking a few kbyte in the "say 4-12
range?" Or in the "a few hundred kbyte would be okay" range? Maybe
you are using the phrase in a way I'm unaccustomed to.
If you are truly limited well below the 64k mark set by tinypy, for
example, then I don't think you are going to get either tinypy or
especially lua in there. Forth is definitely something you might
consider -- I have a hunch (I'm actually ignorant about today's
situation as it's been more than 20 years since I even looked) there
are some implementations that may be quite small and can be fitted
into your application with some work. You will need to supply some
interfaces into your application, I suspect, at the very least. But
also if you are only talking small numbers of kbyte it sounds more to
me as though this is something you are going to pony up on your own.
Because general purpose stuff written by and for folks who know
nothing of your application usually carries a lot of things with it
that you don't need and don't want. And with space at that kind of
premium it's likely you will custom-develop it. On the positive side,
it's not hard at all to write a lexer/parser and execution in very
small space if you keep your eye focused on exactly and only what you
need to have.
Oh. I haven't even brought up the question of the processor and
development tools -- whether it requires (or even supports) reading
flash as data space, for example. When I see that lua can be built
for Linux, I imagine in my mind a case where there is a simple,
virtual memory space for the application which is loaded there by some
operating system and where the code, constants, data, and so on share
a simple, single address space. Your specific processor may...
flummox... this ideal a bit and that may be yet something else you
need to concern yourself about. For example, if you build someone
else's language for your use will the constants need to be stored in
flash but also then copied out into data RAM by the startup code in
order for it to operate properly? (Which then means they add to both
requirements.) What about initialized data? What kind of linking
control do you have in your development tools and how familiar are you
with the various concepts of linkers and application linking?
Of course, maybe you have 100's of kbyte of flash and many tens of
kbyte of RAM and more...
Who can provide better guidance without knowing more about what you
are trying to achieve? Why didn't you write more about it to start?
Jon
- References:
- parser for embedded systems
- From: chrisu
- Re: parser for embedded systems
- From: Jon Kirwan
- parser for embedded systems
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