Re: Pm's YAPC::NA talk online
On Wed, Jun 28, 2006 at 08:12:42AM -0500, Jonathan Scott Duff wrote:
On Wed, Jun 28, 2006 at 04:26:45AM -0500, João Cruz Morais wrote:
- Can I use PGE skipping TGE?
I don't see why not. If you look at the bottom of grammar_rules.pg,
you'll see this:
token syntax_error { ?PGE::Util::die: Syntax error }
where PGE::Util::die is a PIR subroutine. IIUC, everywhere you want
some action to be performed (like code generation for instance) you
could put a PIR subroutine in the grammar just as above and, of
course, write the subroutine to do the action.
It's also worth remembering that one can call executable code
directly from a rule.
token print :lang('PIR') {
expression
{{ $P0 = match['expression']
say $P0
}}
}
- PAST seems just fine as a concept but isn't it useless if I can target
directly to POST with minor fuss?
If one can target POST (or even PIR) directly with minor fuss, then
a separate PAST step might not make much sense. But even with
a relatively simple language (like APL), it's useful to have the
tree-based representation of the program's semantics to be able to
manipulate (e.g., optimizations) rather than trying to work directly
from the parse tree.
Good luck for today's presentation :)
Yeah, good luck Pm :)
Thanks! For those who are interested, the slides from the later
talks are now online.
Perl 6 Compiler Status and the Parrot Compiler Toolkit
http://www.pmichaud.com/2006/pres/yapc-perl6/start.html
Parsers, Perl 6 Rules, and the Parrot Grammar Engine
http://www.pmichaud.com/2006/pres/yapc-parsers/start.html
Parrot Target Practice, Will Coleda
http://www.pmichaud.com/2006/pres/yapc-apl/start.html
Pm
Re: Pm's YAPC::NA talk online
Hi there! I'm new to Parrot but reading from your slides if I understood correctly: - PGE parses input according to a grammar and produces a derivation tree. - TGE transforms the parse tree into an abstract syntax tree. With that said I have some questions (i'm sorry if they were answered already somewhere): - Whats the point of using PGE+TGE over the good old LEX+YACC besides the better regexps? - Can I use PGE skipping TGE? - PAST seems just fine as a concept but isn't it useless if I can target directly to POST with minor fuss? Good luck for today's presentation :) Best regards, João Cruz Morais On 6/27/06, Patrick R. Michaud [EMAIL PROTECTED] wrote: For any who may be interested, my talk slides for Perl 6 Compiler Status and the Parrot Compiler Toolkit (presented today at YAPC::NA) are available at http://www.pmichaud.com/2006/pres/yapc-perl6/slide.html The slides for my second talk Parser, Perl 6 Rules, and the Parrot Grammar Engine will be available tomorrow at http://www.pmichaud.com/2006/pres/yapc-parsers/slide.html Pm
Re: Pm's YAPC::NA talk online
On Wednesday 28 June 2006 02:26, João Cruz Morais wrote: With that said I have some questions (i'm sorry if they were answered already somewhere): - Whats the point of using PGE+TGE over the good old LEX+YACC besides the better regexps? Transforming trees with real objects is a lot easier than mangling C data structures. - Can I use PGE skipping TGE? Yes. - PAST seems just fine as a concept but isn't it useless if I can target directly to POST with minor fuss? Define minor; I've found it much easier in Pheme to go from one tree structure to another rather than from one textual representation to another. After a bit of learning, it's pretty obvious which is the appropriate level for a specific transformation. (Oh, I want to hoist out define-lambda pairs; that's obviously PAST, so that I can scan the whole tree for Sub declarations and get the symbol names later.) -- c
Re: Pm's YAPC::NA talk online
I'm no expert, but I'll hazard some answers:
On Wed, Jun 28, 2006 at 04:26:45AM -0500, João Cruz Morais wrote:
I'm new to Parrot but reading from your slides if I understood correctly:
- PGE parses input according to a grammar and produces a derivation tree.
- TGE transforms the parse tree into an abstract syntax tree.
With that said I have some questions (i'm sorry if they were answered
already somewhere):
- Whats the point of using PGE+TGE over the good old LEX+YACC besides the
better regexps?
I think lex+yacc is approximately equivalent to PGE alone. TGE is
something different.
You can't really say besides the better regexps because that's part of
the point--having better tools with which to transform one language into
another. PGE lets you annotate how the source language fits together
(what's a token and what order the tokens may come in, etc.) while TGE
let's you take those annotations and turn them into alternate
(presumably more useful) representations.
- Can I use PGE skipping TGE?
I don't see why not. If you look at the bottom of grammar_rules.pg,
you'll see this:
token syntax_error { ?PGE::Util::die: Syntax error }
where PGE::Util::die is a PIR subroutine. IIUC, everywhere you want
some action to be performed (like code generation for instance) you
could put a PIR subroutine in the grammar just as above and, of
course, write the subroutine to do the action.
- PAST seems just fine as a concept but isn't it useless if I can target
directly to POST with minor fuss?
It may be uesless in that specific case, but I think it's highly
useful in the general case where the impedence mismatch between the
language you are parsing and the language you are generating may be
large (like say, between a very complex and rich language like Perl6 and
a much simpler language like PIR ;). TGE lets you factor out the
complexity of your source language in incremental steps (as small or as
large steps as you want).
Good luck for today's presentation :)
Yeah, good luck Pm :)
-Scott
--
Jonathan Scott Duff
[EMAIL PROTECTED]
Pm's YAPC::NA talk online
For any who may be interested, my talk slides for Perl 6 Compiler Status and the Parrot Compiler Toolkit (presented today at YAPC::NA) are available at http://www.pmichaud.com/2006/pres/yapc-perl6/slide.html The slides for my second talk Parser, Perl 6 Rules, and the Parrot Grammar Engine will be available tomorrow at http://www.pmichaud.com/2006/pres/yapc-parsers/slide.html Pm
Re: Pm's YAPC::NA talk online
在 2006/6/27 下午 4:41 時，Patrick R. Michaud 寫到： For any who may be interested, my talk slides for Perl 6 Compiler Status and the Parrot Compiler Toolkit (presented today at YAPC::NA) are available at http://www.pmichaud.com/2006/pres/yapc-perl6/slide.html That was a wonderful talk. Thanks Patrick. :-) My talk (Deploying Perl 6) is available at: http://pugs.blogs.com/talks/yapcna-deploy-perl6.pdf http://pugs.blogs.com/talks/yapcna-deploy-perl6.swf http://pugs.blogs.com/talks/yapcna-deploy-perl6.tar.gz (HTML+images) Thanks, Audrey PGP.sig Description: This is a digitally signed message part
