PG-adapting: delete some outdated prooftree information

Delete functions from PG-adapting that have been deleted in the
sources to fix make magic. Delete also some of the outdated
information of the Prooftree configuration section. Note that
this section is still outdated, which is hopefully OK, given the
number of attempts to add Prooftree support for more proof
assistants in the last years.

doc/PG-adapting.texi

@@ -2506,6 +2506,10 @@ tokens (for example, editing documentation or source code files).
 @node Configuring Proof-Tree Visualization
 @chapter Configuring Proof-Tree Visualization
 
+@b{Parts of this section are outdated. Please create an issue at
+github.com/ProofGeneral/Proof General if you have a question for
+adapting Prooftree for a new proof assistant.}
+
 The proof-tree visualization feature was written with the idea of
 supporting Coq as well as other proof assistants. Nevertheless,
 supporting proof-tree visualization for a second proof assistant
@@ -2654,63 +2658,14 @@ proof-tree display is distributed in a few chunks over
 The main task of the Elisp code is to extract goals, undo events
 and information about existential variables from the
 proof-assistant output and to send all this data to Prooftree.
-The Elisp code does also determine if additional output must be
-requested from the proof assistant. In that case it adds
-appropriate commands to @code{proof-action-list}, @pxref{Proof
-script mode}. These additional commands are flagged with
+Additional commands inserted by Prooftree are flagged with
 @code{proof-tree-show-subgoal}, @code{no-goals-display} and
 @code{no-response-display}. The flag
 @code{proof-tree-show-subgoal} ensures that a number of internal
 functions ignore these additional commands. The other two flags
 ensure that their output is neither displayed in the goals nor
 the response buffer.
 
-For the decision about which goals must be sent to Prooftree, the
-Elisp code maintains the following two state variables.
-
-@c TEXI DOCSTRING MAGIC: proof-tree-sequent-hash
-@defvar proof-tree-sequent-hash 
-Hash table to remember sequent ID's.@*
-Needed because some proof assistants do not distinguish between
-new subgoals, which have been created by the last proof command,
-and older, currently unfocussed subgoals.  If Proof General meets
-a goal, it is treated as new subgoal if it is not in this hash yet.
-
-The hash is mostly used as a set of sequent ID's.  However, for
-undo operations it is necessary to delete all those sequents from
-the hash that have been created in a state later than the undo
-state.  For this purpose this hash maps sequent ID's to the state
-number in which the sequent has been created.
-
-The hash table is initialized in @samp{@code{proof-tree-start-process}}.
-@end defvar
-
-
-@c TEXI DOCSTRING MAGIC: proof-tree-existentials-alist
-@defvar proof-tree-existentials-alist 
-Alist mapping existential variables to sequent ID's.@*
-Used to remember which goals need a refresh when an existential
-variable gets instantiated.  To support undo commands the old
-contents of this list must be stored in
-@samp{@code{proof-tree-existentials-alist-history}}.  To ensure undo is
-properly working, this variable should only be changed by using
-@samp{@code{proof-tree-delete-existential-assoc}},
-@samp{@code{proof-tree-add-existential-assoc}} or
-@samp{@code{proof-tree-clear-existentials}}.
-@end defvar
-
-When retracting these two variables must be set to their previous
-state. For @code{proof-tree-sequent-hash} this is done with the
-state numbers that are stored in the hash. For
-@code{proof-tree-existentials-alist} a separate alist stores
-previous states.
-
-@c TEXI DOCSTRING MAGIC: proof-tree-existentials-alist-history
-@defvar proof-tree-existentials-alist-history 
-Alist mapping state numbers to old values of @samp{@code{proof-tree-existentials-alist}}.@*
-Needed for undo.
-@end defvar
-
 
 In Prooftree the separation between generic and proof-assistant
 specific code is less obvious. The Coq specific code is in the
@@ -2825,28 +2780,29 @@ Urgent actions are those that must be executed before
 @code{proof-action-list} to the proof assistant. For execution
 speed, the amount of urgent code should be kept small.
 
-@c TEXI DOCSTRING MAGIC: proof-tree-urgent-action
-@defun proof-tree-urgent-action flags
-Handle urgent points before the next item is sent to the proof assistant.@*
-Schedule goal updates when existential variables have changed and
-call @samp{@code{proof-tree-urgent-action-hook}}. All this is only done if
-the current output does not come from a command (with the
-@code{'proof-tree-show-subgoal} flag) that this package inserted itself.
-
-Urgent actions are only needed if the external proof display is
-currently running. Therefore this function should not be called
-when @samp{@code{proof-tree-external-display}} is nil.
-
-This function assumes that the prover output is not suppressed.
-Therefore, @samp{@code{proof-tree-external-display}} being t is actually a
-necessary precondition.
-
-The not yet delayed output is in the region
-[@code{proof-shell-delayed-output-start}, @code{proof-shell-delayed-output-end}].
+@c TEXI DOCSTRING MAGIC: proof-tree-check-proof-finish
+@defun proof-tree-check-proof-finish last-item
+Urgent action to delay processing at proof end.@*
+This function is called from @samp{@code{proof-shell-exec-loop}} after the
+old item has been removed and before the next item from
+@samp{@code{proof-action-list}} is sent to the proof assistant. Of course
+only when the proof-tree display is active. At the end of the
+proof, this function delays items just following the previous
+proof until all show-goal commands from prooftree and the
+@samp{@code{proof-tree-display-stop-command}} (which switches the dependent
+evar line off for Coq) have been processed.
+
+If this function detects the end of the proof, it moves
+non-priority items following in @samp{@code{proof-action-list}} to
+@samp{@code{proof-tree--delayed-actions}} and sets
+@samp{@code{proof-second-action-list-active}}. When later the command from
+@samp{@code{proof-tree-display-stop-command}} is recognized, the items are
+moved back. If no items follow the end of the previous proof,
+@samp{@code{proof-tree-display-stop-command}} is set to t.
 @end defun
 
 
-The function @code{proof-tree-urgent-action} is called at a point
+The function @code{proof-tree-check-proof-finish} is called at a point
 where it is save to manipulate @code{proof-action-list}. This is
 essential, because @code{proof-tree-urgent-action} inserts goal
 display commands into @code{proof-action-list} when existential
@@ -3844,6 +3800,7 @@ bother the user.  They may include
   @code{'no-error-display}         do not display errors/take error action
   @code{'no-goals-display}         do not goals in @strong{goals} buffer
   @code{'proof-tree-show-subgoal}  item inserted by the proof-tree package
+  @code{'priority-action}          item added via @code{proof-add-to-priority-queue}
 @end lisp
 Note that @code{'invisible} does not imply any of the others. If flags
 are non-empty, interactive cues will be surpressed. (E.g.,
@@ -4347,7 +4304,7 @@ by the filter is to send the next command from the queue.
 Wrapper for @samp{@code{proof-shell-filter}}, protecting against parallel calls.@*
 In Emacs a process filter function can be called while the same
 filter is currently running for the same process, for instance,
-when the filter bocks on I/O. This wrapper protects the main
+when the filter blocks on I/O. This wrapper protects the main
 entry point, @samp{@code{proof-shell-filter}} against such parallel,
 overlapping calls.