camlp4: From AST to shortcuts

camlp4: From AST to shortcuts

[Joel Reymont]

Suppose I'm debugging a camlp4 extension and get the following AST

Ast.TyId (_loc, Ast.IdLid (_loc, "int"))

what's the best way of figuring out that this correspods to this bit?

<:ctyp< int >>

Do I grep the sources and if so what files?

This is a rather simple example but I'm trying to teach myself to  
fish. Ultimately, I want to add initializer code and fields to the  
AST resulting from a class declaration.

	Thanks, Joel

--
http://wagerlabs.com

Re: [Caml-list] camlp4: From AST to shortcuts

[Nicolas Pouillard]

Excerpts from joelr1's message of Tue Oct 09 23:41:14 +0200 2007:
> Suppose I'm debugging a camlp4 extension and get the following AST
> 
> Ast.TyId (_loc, Ast.IdLid (_loc, "int"))
>
> what's the best way of figuring out that this correspods to this bit?
> 
> <:ctyp< int >>

With the pretty printer.

It starts like the last time.

$ rlwrap ocaml camlp4of.cma                                                                                                                                                                                                               
open Camlp4.PreCast;;                                                                                                                                                                                                                     
module PP = Camlp4.Printers.OCaml.Make(Syntax);;                                                                                                                                                                                          
let pp = new PP.printer ();;                                                                                                                                                                                                              
let ghost = Loc.ghost;;                                                                                                                                                                                                                   
module PP = Camlp4.Printers.OCaml.Make(Syntax);;                                                                                                                                                                                          

let _loc = ghost;;
Format.eprintf "<:ctyp< %a >>@." pp#ctyp (Ast.TyId (_loc, Ast.IdLid (_loc, "int")));;

> Do I grep the sources and if so what files?

In  fact you should look at the wiki first especially the Abstract_Syntax_Tree
[3]  page.  The  wiki  also  states about "Relevant Source Files" [2]. In this
case the most relevant file is Camlp4Ast.partial.ml [1].

[1]: http://camlcvs.inria.fr/cgi-bin/cvsweb/ocaml/camlp4/Camlp4/Camlp4Ast.partial.ml?rev=1.3;content-type=text%2Fplain
[2]: http://brion.inria.fr/gallium/index.php/Relevant_Source_Files
[3]: http://brion.inria.fr/gallium/index.php/Abstract_Syntax_Tree

> This is a rather simple example but I'm trying to teach myself to  
> fish. Ultimately, I want to add initializer code and fields to the  
> AST resulting from a class declaration.

See my other mail about class initializer.

Good fishing...
-- 
Nicolas Pouillard aka Ertai

Re: [Caml-list] camlp4: From AST to shortcuts

[Joel Reymont]

On Oct 10, 2007, at 1:36 PM, Nicolas Pouillard wrote:

> With the pretty printer.
> ...
> let _loc = ghost;;
> Format.eprintf "<:ctyp< %a >>@." pp#ctyp (Ast.TyId (_loc, Ast.IdLid  
> (_loc, "int")));;

That doesn't quite work since I have to know to use a ctyp. I was  
wondering if there was a way to figure out the shortcut without  
knowing about ctyp beforehand.

Then again, I looked at Camlp4/Camlp4Ast.partial.ml and, conveniently  
enough, TyId is located under ctyp whereas CrIn (class initializer;  
what's the "r" in Cr?) is under class_str_item.

Can it be THAT simple?

	Thanks, Joel

--
http://wagerlabs.com

Re: [Caml-list] camlp4: From AST to shortcuts

[Nicolas Pouillard]

Excerpts from joelr1's message of Wed Oct 10 15:00:54 +0200 2007:
> 
> On Oct 10, 2007, at 1:36 PM, Nicolas Pouillard wrote:
> 
> > With the pretty printer.
> > ...
> > let _loc = ghost;;
> > Format.eprintf "<:ctyp< %a >>@." pp#ctyp (Ast.TyId (_loc, Ast.IdLid  
> > (_loc, "int")));;
> 
> That doesn't quite work since I have to know to use a ctyp. I was  
> wondering if there was a way to figure out the shortcut without  
> knowing about ctyp beforehand.
> 
> Then again, I looked at Camlp4/Camlp4Ast.partial.ml and, conveniently  
> enough, TyId is located under ctyp whereas CrIn (class initializer;  
> what's the "r" in Cr?) is under class_str_item.
> 
> Can it be THAT simple?

Of    course!   The   convention   for   quotations   given   by   camlp4   is
<:type_name<...>>,  <:expr<...>>  is  for  Ast.expr, <:class_str_item<...>> is
for Ast.class_str_item...

-- 
Nicolas Pouillard aka Ertai