Greetings,
On 9/9/12 6:29 PM, Wojciech Meyer wrote:

Gabriel Scherer <gabriel.scherer@gmail.com> writes:

This is useful for debugging purposes, and for some (minor) modes of
use of Camlp4. However, for most Camlp4 development, this has the
severe downside of losing the location information of the original
file, if I understand correctly. This means that you don't want to use
it as a transparent step towards compilation, but only in exceptional
situations where the developers will re-edit the output code.

I think I've to say I disagree it's not useful, when I'm developing a
syntax extension on top of Camlp4 I really want to see the generated
code. Moreover to understand some of the more complicated syntax
extensions like type_conv, deriving, FoldGenerator I need to look at the
expanded code to understand how to use it - last time I hit the same

Yes, it's damn useful not only for bootstrapping, but also for developing to locate type errors. But there's something wrong with Camlp4's printer, it has *4* printers in total, writing a printer for an Ast which has no backend is totally useless. In my branch of camlp4, *I removed all those 4 printers and using tools/pprintast.ml* in ocaml's compiler source tree(with some my own bug fixes), and it works very well.
Btw, are you in ICFP? we could have a talk about Camlp4 :-)

problem it was actually 'deriving-ocsigen' when I needed to implement my
own Show module - it's just much faster to see what's being generated
for the usual case, then trying to figure out from the recipe in the
documentation.  Otherwise for bootstrapping purposes, you might want to
pre-generate some code too and put into the repository.

--
Wojciech Meyer
http://danmey.org