From 7993d50d0d1dd029b34745e1ee089d9cf7c5ffbd Mon Sep 17 00:00:00 2001
From: aspiwack
Date: Fri, 24 Aug 2012 17:36:36 +0000
Subject: Experimental support for a comment in the files' preamble in
 extraction.

Scheme comments are output on a single line because Ocaml's Format
module which serves as a backend to Pp has an integer, rather than a string
as identation value, so we cannot make it so that each new line in the
comment starts with ";; ".

I've tried something with Pp.ifb but it was hackish at best and had somewhat
strange results.

Known bug: as Pp.std_ppcmds is non-persistent, the comment is actually printed
only once per Extraction command, even if it outputs several files.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@15763 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 plugins/extraction/scheme.ml | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'plugins/extraction/scheme.ml')

diff --git a/plugins/extraction/scheme.ml b/plugins/extraction/scheme.ml
index 03a7c20062..27529258ba 100644
--- a/plugins/extraction/scheme.ml
+++ b/plugins/extraction/scheme.ml
@@ -28,7 +28,10 @@ let keywords =
       "error"; "delay"; "force"; "_"; "__"]
     Idset.empty
 
-let preamble _ _ usf =
+let pp_comment s = str";; "++h 0 s++fnl ()
+
+let preamble _ comment _ usf =
+  pp_comment comment ++ fnl () ++
   str ";; This extracted scheme code relies on some additional macros\n" ++
   str ";; available at http://www.pps.jussieu.fr/~letouzey/scheme\n" ++
   str "(load \"macros_extr.scm\")\n\n" ++
@@ -223,7 +226,7 @@ let scheme_descr = {
   preamble = preamble;
   pp_struct = pp_struct;
   sig_suffix = None;
-  sig_preamble = (fun _ _ _ -> mt ());
+  sig_preamble = (fun _ s _ _ -> pp_comment s ++ fnl () ++ fnl ());
   pp_sig = (fun _ -> mt ());
   pp_decl = pp_decl;
 }
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