Re: Doing mini-languages in CL

From: Greg Menke (gregm-news_at_toadmail.com)
Date: 02/12/04 

Date: 11 Feb 2004 23:10:07 -0500

"Will Hartung" <willh@msoft.com> writes:

> "Greg Menke" <gregm-news@toadmail.com> wrote in message
> news:m3oes5grj5.fsf@europa.pienet...
>
> > 8052 (the one with rom'ed Basic) w/ 32K ram. The output of the
> > mini-language would be assembly- the assembler I have for it is
> > reasonable, I'm quite happy to defer all the instruction coding and
> > address fixup grunt work to it.
>
> So, simply put the goal is to write a pure compiler, not an emulator or a
> simulator or anything like that. Rather, you put in "GregLisp", and out come
> 8052 Assembly to be assembled, hexified, downloaded, burnt, plugged in and
> tested just like any other bit of 8052 Assembly.

Thats it in a nutshell. From that perspective, my question was how to
arrange the symbol names for the functions "GregLisp" implements.

 
> If your primary goal in using CL is mostly for its macro facility, I would
> stop right there.

I was more hoping to leverage the reader, with the ability to use
macros as something thats potentially useful- but which I probably
don't understand how to arrange at the moment.

> When you write your own compiler, as long as you have the ability to call
> (greg-compile sexpr), you basically have a macro facility built in to your
> own system, rather than having to "fight" wil CLs.
>
> Your compiler will already take S-exprs, but there's nothing that says those
> S-exprs have to come solely from source code for the microcontroller. You
> can easily do something like this:

<snip sample code, Thanks!>

> I stored the respective function compilers in a hash table (craftily named
> *functions*).
>
> If you rely on Symbols and property lists (something I didn't think about
> being more in Java mode that Lisp mode), then you associate the compiler
> function directly with the symbol rather than building up a table like I
> did. Whatever floats your boat.

I get the impression that figuring this out will be a good education
for me on how Lisp handles symbols.

 
> But for basic stuff, using S-exprs, it's really pretty darn easy to work it
> all out.

Thats what I was going for.
 
> My compiler was pretty simple, pretty limited and relied on nice people like
> me feeding it good code, but when you can essentially create your parse tree
> on the fly and feed it back into the compiler itself, things get pretty easy
> pretty darn fast, and you find you won't necessarily need macros. Now, if
> you want macros in your mini-language, that's a different animal entirely.
>
> Luck.
>
> Regards,
>
> Will Hartung
> (willh@msoft.com)

Thanks! I think those are the hints I needed- next I'll see if I can
do something.

Gregm

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