coqpp: add new ![] specifiers for structured proof interaction

![proof_stack] is equivalent to the old meaning of ![proof]: the body
has type `pstate:Proof_global.t option -> Proof_global.t option`

The other specifiers are for the following body types:

~~~
![open_proof] `is_ontop:bool -> pstate`

![maybe_open_proof] `is_ontop:bool -> pstate option`

![proof] `pstate:pstate -> pstate`

![proof_opt_query] `pstate:pstate option -> unit`

![proof_query] `pstate:pstate -> unit`
~~~

The `is_ontop` is only used for the warning message when declaring a
section variable inside a proof, we could also just stop warning.

The specifiers look closely related to stm classifiers, but currently
they're unconnected. Notably this means that a ![proof_query] doesn't
have to be classified QUERY.

![proof_stack] is only used by g_rewrite/rewrite whose behaviour I
 don't fully understand, maybe we can drop it in the future.

For compat we may want to consider keeping ![proof] with its old
meaning and using some new name for the new meaning. OTOH fixing
plugins to be stricter is easier if we change it as the errors tell us
where it's used.

1 files changed, 7 insertions, 9 deletions

diff --git a/doc/plugin_tutorial/tuto1/src/g_tuto1.mlg b/doc/plugin_tutorial/tuto1/src/g_tuto1.mlg
index 147b0df567..300d62285a 100644
--- a/doc/plugin_tutorial/tuto1/src/g_tuto1.mlg
+++ b/doc/plugin_tutorial/tuto1/src/g_tuto1.mlg
@@ -145,13 +145,11 @@ END
   it gives an error message that is basically impossible to understand. *)
 
 VERNAC COMMAND EXTEND ExploreProof CLASSIFIED AS QUERY
-| ![ proof ] [ "Cmd9" ] ->
-  { fun ~pstate:ontop ->
-    Option.iter (fun ontop ->
-        let pstate = Proof_global.get_current_pstate ontop in
-        let sigma, env = Pfedit.get_current_context pstate in
-        let pprf = Proof.partial_proof Proof_global.(give_me_the_proof pstate) in
-        Feedback.msg_notice
-          (Pp.prlist_with_sep Pp.fnl (Printer.pr_econstr_env env sigma) pprf)) ontop;
-    ontop }
+| ![ proof_query ] [ "Cmd9" ] ->
+  { fun ~pstate ->
+    let sigma, env = Pfedit.get_current_context pstate in
+    let pprf = Proof.partial_proof Proof_global.(give_me_the_proof pstate) in
+    Feedback.msg_notice
+      (Pp.prlist_with_sep Pp.fnl (Printer.pr_econstr_env env sigma) pprf)
+  }
 END