Re: [Caml-list] Camlp4-free implementation of stream parsers (was camlp4 & OCaml 4.08)

["Jocelyn Sérot" <jocelyn.serot@uca.fr>]

HI Daniil,

Thanks for the example. It clearly shows how to embed a Menhir-specified parser into an existing program.

I still think, however that using Menhir for parsing arithmetic expressions is a bit overkill.

I’m having a look at Angstrom (and all the other parser combinator libs cited on the corresp. page).
It seems simpler. 

Jocelyn

Le 24 juil. 2019 à 17:31, Daniil Baturin <daniil@baturin.org> a écrit :

> Hi Jocelyn,
> 
> I've completed the first version of my project, so now I can start
> looking into this again!
> 
> There's a third option: parser combinators like angstrom.
> My experience with Menhir is very positive though. After initial
> struggle, I came to like its new incremental API and declarative error
> reporting.
> 
> Here's my parser for an extended BNF:
> Menhir grammar:
> https://github.com/dmbaturin/bnfgen/blob/master/src/bnf_parser.mly
> Parser driver that feeds it tokens:
> https://github.com/dmbaturin/bnfgen/blob/master/src/parse_bnf.ml
> Error messages:
> https://github.com/dmbaturin/bnfgen/blob/master/src/bnf_parser.messages
> Error message module build:
> https://github.com/dmbaturin/bnfgen/blob/master/src/dune#L6-L8
> 
> On 7/24/19 10:10 PM, Jocelyn Sérot wrote:
>> Hi Daniil (and everyone interested by the subject),
>> 
>> Did you have a closer look at this ? 
>> 
>> I’m still hesitating between these three approaches for replacing the implementation of the small arithm expression parser used in Lascar [1] :
>> 
>> i. rewrite it using the basic fns provided by the Stream library (pro: no additionnal dependency, cons: not so trivial..)
>> 
>> ii. replace camlp4 by camlp5 (pro: straightforward, cons: long term maintainability of camlp5 (?)) 
>> 
>> iii. rewrite it using ocamlex/menhir and embed it in the main code (pro: « standard » soon; cons: a bit heavy)
>> 
>> Jocelyn
>> 
>> [1] https://github.com/jserot/lascar/blob/master/src/lib/fsm_expr.ml, lines 70–112
>> 
>> Le 2 juil. 2019 à 11:25, Daniil Baturin <daniil@baturin.org> a écrit :
>> 
>>> Hi Jocelyn,
>>> Camlp5 is still sort of maintained, but I don't think it's going to be
>>> developed beyond compatibility updates.
>>> For syntax extensions, everyone is switching to PPX.
>>> 
>>> From a quick look, it seems like the only bit of camlp4 you use is
>>> stream expressions.
>>> This is one of the things PPX can't do (on purpose, since it doesn't
>>> allow _arbitrary_ extensions),
>>> but I don't think just using streams directly is going to make code much
>>> longer.
>>> 
>>> Or I missed some other camlp4 bits?
>>> 
>>> I'm ready to work on a patch if you are open to it.
>>> 
>>> On 7/2/19 1:44 PM, Jocelyn Sérot wrote:
>>>> Le 29 juin 2019 à 17:15, Daniil Baturin <daniil@baturin.org> a écrit :
>>>> 
>>>>> Perhaps we should make some coordinated effort to help them.
>>>>> I've just sent a pull request to the ocamldot maintainer that enables
>>>>> the graphviz files parsing and printing modules
>>>>> to build and work with 4.08. The GTK parts have their own issues.
>>>>> Next I'm going to look into LASCAR/RFSM (packages that interest me first ;).
>>>>> 
>>>> Hi Daniil,
>>>> 
>>>> I’ve been been thinking of removing the dependency of Lascar and RFSM on camlp4 for a while.
>>>> Is switching to CamlP5 a good alternative ? 
>>>> 
>>>> Jocelyn
>>>> 
>>>> 
>>> 
> 
>