Building a parser with Camlp4

Building a parser with Camlp4

[David Teller]

     Hi list (Nicolas Pouillard, in particular),

 I'll probably need to rewrite my (not-fully-complete-yet) parser for
JavaScript 2 and I'm considering using Camlp4 as a parser generator for
a completely-non-OCaml target language. Now, before I do that, I have a
few questions in mind:

* What is the power of Camlp4 ? The documentation says LL(1+epsilon) but
the examples look like LL(k) with a possibly large k.

* How do I plug-in a lexer written with ULex ?

* Camlp4 looks relatively slow -- is it much slower than Yacc ?



Thanks,
 David

Re: [Caml-list] Building a parser with Camlp4

[Nicolas Pouillard]

Excerpts from David Teller's message of Wed Nov 28 08:14:00 +0100 2007:
>      Hi list (Nicolas Pouillard, in particular),
Hi,

>  I'll probably need to rewrite my (not-fully-complete-yet) parser for
> JavaScript 2 and I'm considering using Camlp4 as a parser generator for
> a completely-non-OCaml target language. Now, before I do that, I have a
> few questions in mind:
> 
> * What is the power of Camlp4 ? The documentation says LL(1+epsilon) but
> the examples look like LL(k) with a possibly large k.

Yes `k' is the number of terminals at the beginning of a rule.

> * How do I plug-in a lexer written with ULex ?

It don't remember but cduce does that, and is updated to the new version of Camlp4.

> * Camlp4 looks relatively slow -- is it much slower than Yacc ?

Yes, that's the cost of dynamic extensibility.
-- 
Nicolas Pouillard aka Ertai

Re: [Caml-list] Building a parser with Camlp4

[Yitzhak Mandelbaum]

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A more important question (IMHO) : does it matter? I.e. how fast do  
you need the parser to be?


On Nov 28, 2007, at 4:57 AM, Nicolas Pouillard wrote:

>> * Camlp4 looks relatively slow -- is it much slower than Yacc ?
>
> Yes, that's the cost of dynamic extensibility.

--------------------------------------------------
Yitzhak Mandelbaum
AT&T Labs - Research

http://www.research.att.com/~yitzhak



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Re: [Caml-list] Building a parser with Camlp4

[David Teller]

Well, with my current parser, parsing the standard library of JavaScript
2 (a few thousand lines) several minutes (with debugging code on). Which
is a bit too much. So, no, I can't answer your question but yes,
performance does matter.

Cheers,
 David



On Wed, 2007-11-28 at 07:38 -0500, Yitzhak Mandelbaum wrote:
> A more important question (IMHO) : does it matter? I.e. how fast do
> you need the parser to be?