Re: [Caml-list] Array.make exception and parser

[Yitzhak Mandelbaum <yitzhakm@cs.princeton.edu>]

Daniel,

I'm not sure you want to bring the ocaml compiler as proof-case for your argument. Its parser is generated by ocamlyacc, which is a relatively ancient tool (the codebase is a modified version of the Berkeley Yacc, written in C. I'm guessing that the large majority of that code is well over 20 years old at this point). There are more modern LR parser generators which do a far better job and there's no theoretical reason they can't do just as well as LL tools.

Also, you might want to keep in mind that this is largely a zero-sum game. If the developers spend more time on the parser, that's less time on the rest of the compiler or new research. So, saving developer time does, in fact, mean *more* user convenience -- just in a different part of the compiler.

Yitzhak

On Jan 4, 2011, at 2:30 PM, Daniel Bünzli wrote:

>> For what it's worth, here is my answer: an LR parser generator (like Menhir)
>> accepts a larger class of grammars without refactoring (no need to eliminate
>> left recursion, identify common left factors, etc.) and is also able to
>> *explain* why the grammar is ambiguous (or rather, why it lies outside the LR
>> class), which a combinator-based approach cannot do.
> 
> So everybody trades developer convenience for end user convenience --
> I mean, the syntax errors produced by LR parsers are just terrible,
> the ocaml compiler is here to witness that.
> 
> That's depressing.
> 
> Daniel
> 
> -- 
> Caml-list mailing list.  Subscription management and archives:
> https://sympa-roc.inria.fr/wws/info/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
> 

-----------------------------
Yitzhak Mandelbaum