* Re: [Caml-list] camlp5 pa_pragma
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@ 2012-02-21 5:00 ` Daniel de Rauglaudre
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From: Daniel de Rauglaudre @ 2012-02-21 5:00 UTC (permalink / raw)
To: Caml List
Hi,
On Tue, Feb 21, 2012 at 12:56:10AM +0100, bob zhang wrote:
> I noticed that camlp5 has a pretty nice extension pa_pragma, would
> you like shed some light on this?
It allows to execute code at syntactic analysis phase and, therefore,
to do syntactic extensions without having to previously compile a file,
containing these extensions.
I am not very satisfied of it, because the evaluation supposes to type
expressions, or to try to type them, what, normally, Camlp* are not
supposed to do. It is complicated, incomplete and perhaps dangerous.
To be correct, it should embark the OCaml toplevel and, therefore, the
whole OCaml compiler, what is not a good idea.
I tried to limit it to evaluation of syntax extensions but it remains
complicated. Probably we should define a precise sub-language for it.
> (I mean the design issue, and the its defect) I would be happy to
> port it to camlp4 if it's not too difficult
I am afraid it is.
--
Daniel de Rauglaudre
http://pauillac.inria.fr/~ddr/
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