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, 2 insertions, 8 deletions

diff --git a/plugins/extraction/g_extraction.mlg b/plugins/extraction/g_extraction.mlg
index d43d90af60..487accbc9b 100644
--- a/plugins/extraction/g_extraction.mlg
+++ b/plugins/extraction/g_extraction.mlg
@@ -178,12 +178,6 @@ END
 (* Show the extraction of the current proof *)
 
 VERNAC COMMAND EXTEND ShowExtraction CLASSIFIED AS QUERY
-| ![ proof ] [ "Show" "Extraction" ]
-  -> { fun ~pstate:ontop ->
-    let pstate = Option.map Proof_global.get_current_pstate ontop in
-    let pstate = match pstate with
-      | None -> CErrors.user_err Pp.(str "No ongoing proof")
-      | Some pstate -> pstate
-    in
-    let () = show_extraction ~pstate in ontop }
+| ![ proof_query ] [ "Show" "Extraction" ]
+  -> { show_extraction }
 END