RTL/tree (from gcc) and Scheme

[Per Bothner]

Valery A.Khamenya wrote:

> PB> Not every eval - just the non-trivial ones.  It does not compile
> PB> a function application - but it does compile a function definition,
> PB> including lambda expressions and let expressions.
> 
> hm... still, what does mean "just the non-trivial ones"?

Loosely, anything that involves lexical scoping is "non-trivial".
Function application, variable references, literals, conditionals,
and begin forms are trivial.  Lambda and let forms are non-trivial.

> hmm, after reading this I've tried to get last release under cygwin
> first. This:
> ftp://ftp.gnu.org/pub/gnu/kawa/kawa-1.7.tar.gz ,
> ftp://ftp.gnu.org/pub/gnu/kawa/kawa-1.7.jar and this
> ftp://ftp.gnu.org/pub/gnu/kawa/kawa-1.7-src.zip are not accessible
> for me at least. :-(

There was a break-in at the GNU site, and they are verifying the
various files.  I don't know when they'll be back or whether I can
do something to improve this.

If you can use CVS, I suggest getting Kawa from CVS - which is
using a different server.

> There is a plenty of reasons. Let's just consider main things.
> 
> 1. Power of portability.
> 
>    gcc is extremely portable. Does history know something as portable
>    as gcc today? This power of portability belongs just to C/C++,
>    FORTRAN and a few other newly introduced languages. What about
>    other languages?

I don't see having trees available "at run-time" will help here.
There is nothing in principle that prevents people from writing
other langauge implementations - it just isn't as easy as one
would like, especially since the API isn't a frozen stable API.

> 3. Exclusive features like "compile to native in run-time".

You're not asking for "RTL/trees at run-time" but "a library interface
for invoking Gcc from an application".  That is very difficult, for both
technical and licensing reasons.

> what should I add to the 4 issues above? Of course there are more
> points, but let's try to keep this important argumentation in focus
> without blurring. 

That helped explain what your're looking for.  However, it's not going
to be easy ...

> I do hope I spend my time not in vain. There are not that much people
> able to move things like you can. I guess, you felt already that RTL
> is tooo much close to Scheme

No, RLT is no-where near Scheme.  You're confused by the Lisp-like
syntax used when printing out RTL.  However, it is way too low-level
to be useful for Scheme.   A Scheme GCC compiler would generate trees,
not RTL. Or do you mean using Scheme to manipulate RLT, perhaps
writing new implementations in Scheme, etc?  There doesn't seem to be
any advantage in that:  Processing RTL is always plenty time-consuming,
and using Scheme would just make things slower without much benefit.

> and it is a big mistake just to ignore
> this benefit and not to implement Scheme based on it. (Maybe it was
> just one of motivations for you to implement kawa?)

No.  The original motivation came from a contract at Cygnus.

> BTW, are you still along working on kawa?

Yes - even occasionally getting paid for it.  I'm working hard on
implementing XQuery (http://www.w3.org/XML/Query) using the
Kawa compiler framework, but also working on improving the
Scheme implementation.

> P.P.S. Time in Germany is close to midnight already but I hope to get
>      some answers to this email today :-)

I assumed from your domain name you were in Russia.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/