Re: [Caml-list] how (within camlp4 printer) can I traverse AST ?

[Gabriel Scherer <gabriel.scherer@gmail.com>]

I think that just replacing Camlp4.Sig.Syntax and
Camlp4.Register.Printer by Camlp4.Sig.Camlp4Syntax and
Camlp4.Register.OCamlPrinter works.

I'm not sure what you mean by "using concrete instead of abstract
syntax"; if you mean using quotations instead of writing the AST
constructor names in full, then that is not related to printers
specifically. Feel free to look at existing syntax extensions, such as
http://bluestorm.info/camlp4/list.php , for inspiration. But none of
them, if I remember correctly, touch the printers.

On Wed, Feb 1, 2012 at 1:01 PM, Matej Košík
<5764c029b688c1c0d24a2e97cd764f@gmail.com> wrote:
> On 01/31/2012 10:58 PM, Gabriel Scherer wrote:
>> Sig.Ast is the most general structure available, that you use if you
>> want to manipulate any kind of grammar for Camlp4. If you know the AST
>> you're manipulating corresponds to an OCaml program, you should use
>> the more specific Sig.Camlp4Ast signature (as advertized in the
>> documentation page for Sig.Ast, btw.). Registering a printer for
>> Sig.Camlp4Ast is done with Register.OcamlPrinter, and if you want to
>> see a full-blown example of printer, you just have too look at
>> camlp4/Camlp4/Printers/OCaml.ml in the ocaml source.
>
> Thank you.
>
> Concerning camlp4/Camlp4/Printers*.ml I am struggling with two problems:
>
> 1. these examples are not compiled with ordinary ocamlc/camlp4 tools but
> with special ocamlc/camlp4* version built at the "boot time" which are
> not interchangeable with regular ocamlc/camlp4* programs. If I try to
> use regular ocamlc/camlp4* tools in an attempt to compile those
> printers, I will get syntax errors in those printers.
>
> 2. the code that registers the printers is not in printers themselves
> but it is located in another file, in another context and it is not
> obvious how to achieve this action in the context of the code of
> individual printers (in an analogous way how sample printer
>  http://brion.inria.fr/gallium/index.php/Setup_a_new_printer
> directly registers itself.
>
> How would the printer described here:
>  http://brion.inria.fr/gallium/index.php/Setup_a_new_printer
> look like if I wanted to use concrete instead of abstract syntax---like in:
> - DumpOCamlAst
> - OCaml.ml
> - OCamlr.ml
> ?
>
> (So that presumably I can compile the printer as shown in the HOWTO.)