ocamlbuild and bootstrapping projects

ocamlbuild and bootstrapping projects

[erickt]

I was trying to adapt the parser dypgen (http://dypgen.free.fr/)'s build
system to use ocamlbuild, but I ran into a problem. The final dypgen
grammar is generated by an internal intermediary generator called pgen.
The problem I'm having is that I don't know how to get ocamlbuild to
automatically build pgen before we can process a %.dyp file. I suppose I
could do this in two separate calls to ocamlbuild, but I feel like this
can be done using a plugin. Is this possible?

If this helps, here are all the files:

all the files shared between the two generators:
dyplib/automaton.ml
dyplib/dyp.ml
dyplib/dyp.mli
dyplib/dyplib.mllib
dyplib/gs.ml
dyplib/priority_by_relation.ml

the intermediary generator. This isn't supposed to be an external tool:
generators/pgen/pgen.ml
generators/pgen/pgen_lexer.mll
generators/pgen/pgen_parser_param.ml

the external parser:
generators/dypgen/argument.ml
generators/dypgen/dypgen.ml
generators/dypgen/dypgen_lexer.mll
generators/dypgen/dypgen_parser.dyp  <- the file that needs to be parsed
with pgen
generators/dypgen/insert_linenum.mll
generators/dypgen/parse_tree.mli


Thanks for any help!

-e

Re: [Caml-list] ocamlbuild and bootstrapping projects

[Erick Tryzelaar]

erickt@dslextreme.com wrote:
> I was trying to adapt the parser dypgen (http://dypgen.free.fr/)'s build
> system to use ocamlbuild, but I ran into a problem. The final dypgen
> grammar is generated by an internal intermediary generator called pgen.
> The problem I'm having is that I don't know how to get ocamlbuild to
> automatically build pgen before we can process a %.dyp file. I suppose I
> could do this in two separate calls to ocamlbuild, but I feel like this
> can be done using a plugin. Is this possible?

For those that are interested, here's the solution I came up with. We 
use the "build" function we get in the rule to dynamically dispatch the 
building of the parser if we haven't generated it yet:

myocamlbuild.ml:
dispatch begin function
  | After_rules ->
      rule "dypgen: .dyp -> .ml & .mli"
        ~deps:["%.dyp"]
        ~prods:["%.ml"; "%.mli"]
        begin fun env build ->
          let dyp = env "%.dyp" in
          let tags = tags_of_pathname dyp++"ocaml"++"parser" in
         
          (* Since pgen and dypgen programs use the same extension, we need
           * to be able to switch between the two. Do this by tagging 
the pgen
           * files with "use_pgen".
           * I'm not sure how we should do byte/native, so we'll just 
use the
           * native. *)
          let dypgen, tags =
            if Tags.mem "use_pgen" tags
            then "dyp/generators/pgen/pgen.native", tags++"pgen"
            else "dyp/generators/dypgen/dypgen.native", tags++"dypgen"
          in
           
          (* try to build the parser if it doesn't exist yet *)
          List.iter begin function
            | Outcome.Good o -> ()
            | Outcome.Bad exn -> raise exn
          end (build [[dypgen]]);
           
          Cmd(S[A dypgen; T tags; Px dyp])
        end;
  | _ -> ()
end;;

Re: [Caml-list] ocamlbuild and bootstrapping projects

[Nicolas Pouillard]

Your solution is quite good and follows ocamlbuild principles.

Excerpts from Erick Tryzelaar's message of Mon Aug 06 12:11:16 +0200 2007:
> erickt@dslextreme.com wrote:
> > I was trying to adapt the parser dypgen (http://dypgen.free.fr/)'s build
> > system to use ocamlbuild, but I ran into a problem. The final dypgen
> > grammar is generated by an internal intermediary generator called pgen.
> > The problem I'm having is that I don't know how to get ocamlbuild to
> > automatically build pgen before we can process a %.dyp file. I suppose I
> > could do this in two separate calls to ocamlbuild, but I feel like this
> > can be done using a plugin. Is this possible?
> 
> For those that are interested, here's the solution I came up with. We 
> use the "build" function we get in the rule to dynamically dispatch the 
> building of the parser if we haven't generated it yet:
> 
> myocamlbuild.ml:
> dispatch begin function
>   | After_rules ->
>       rule "dypgen: .dyp -> .ml & .mli"
>         ~deps:["%.dyp"]
>         ~prods:["%.ml"; "%.mli"]
>         begin fun env build ->
>           let dyp = env "%.dyp" in
>           let tags = tags_of_pathname dyp++"ocaml"++"parser" in
>          
>           (* Since pgen and dypgen programs use the same extension, we need
>            * to be able to switch between the two. Do this by tagging 
> the pgen
>            * files with "use_pgen".
>            * I'm not sure how we should do byte/native, so we'll just 
> use the
>            * native. *)
>           let dypgen, tags =
>             if Tags.mem "use_pgen" tags
>             then "dyp/generators/pgen/pgen.native", tags++"pgen"
>             else "dyp/generators/dypgen/dypgen.native", tags++"dypgen"
>           in
>            
>           (* try to build the parser if it doesn't exist yet *)
>           List.iter begin function
>             | Outcome.Good o -> ()
>             | Outcome.Bad exn -> raise exn
>           end (build [[dypgen]]);

You can use the Outcome.ignore_good function.

List.iter Outcome.ignore_good (build [[dypgen]])

>            
>           Cmd(S[A dypgen; T tags; Px dyp])
>         end;
>   | _ -> ()
> end;;
> 

-- 
Nicolas Pouillard aka Ertai