Re: Ada Interpreter using YACC or BISON

Christoph Bochsler <e3bochsl@twi.ch> wrote:
>Hello I try to generate an interpreter for an Ada-like language. I had
>a short look to the FLEX/BISON utilities but I actually don't know if
>it's possible to build an interpreter instead of a compiler. I need a
>program which can do the following:
>
>Source file example:
>
>a int;
>a=0;
>for (i==1,i<10,i++) do
> COMMAND(a+i);


BTW, you may want to crosspost to comp.lang.ada from now on with
questions like this.


Well, that looks much more C-like than Ada-like to me :-) Writing an
Ada interpreter would be a bit of a challenge, especially considering
Ada 95 features, which can be tricky. Given my limited knowledge, I'd
say it's just as easy to write a C++ interpreter as an Ada
interpreter; that is, almost impossible :-)




>[It's possible, but it's not easy. I always tell people to make one pass to
>translate to byte codes, then intepret the byte codes. -John]


For a good starting point, perhaps you should look at the sources for
the GNU Ada compiler (ftp://ftp.cs.nyu.edu/pub/gnat). There's a LOT
of good stuff in there, but none of it is FLEX/BISON based :-)


Intermetrics wrote an Ada compiler that generates Java bytecode, but
those sources aren't publicly available :-(


I also recomment ANTLR 2.00 as your parsing tool. We've been pretty
pleased with what we've seen so far. To hell with FLEX :-)
(java.magelang.com). ANTLR 2.00, by the way, is the reincarnation of
PCCTS.


Good luck!
--
Booch Components Homepage: www.rivatech.com ||Ada Homepage: www.adahome.com
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