[nongnu] elpa/sweeprolog d757d27485 2/4: ADDED: Persistent history for Sweep top-levels

[ELPA Syncer]

branch: elpa/sweeprolog
commit d757d274856b6fb598813cf20ebffbce0659ec2f
Author: Eshel Yaron <me@eshelyaron.com>
Commit: Eshel Yaron <me@eshelyaron.com>

    ADDED: Persistent history for Sweep top-levels
    
    This adds a new user option that controls the value of
    'comint-input-ring-file-name' in Sweep top-level buffers.
    
    * sweeprolog.el (sweeprolog-top-level-persistent-history): New user
    option.
    (sweeprolog-top-level-sentinel)
    (sweeprolog-top-level-setup-history): New functions.
    (sweeprolog-top-level-setup-buffer): Call
    'sweeprolog-top-level-setup-history' when creating a new top-level
    buffer.
---
 README.org    | 76 ++++++++++++++++++++++++++++++++++++-----------------------
 sweeprolog.el | 59 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 106 insertions(+), 29 deletions(-)

diff --git a/README.org b/README.org
index 5c5462717f..20297ce44f 100644
--- a/README.org
+++ b/README.org
@@ -2242,29 +2242,58 @@ the entry corresponding to the wanted top-level (see 
[[The Top-level
 Menu buffer]]).
 
 For more information about interrupting threads in SWI-Prolog, see
-[[https://www.swi-prolog.org/pldoc/man?section=thread-signal][Signaling 
threads in the SWI-Prolog manual]].
+[[https://www.swi-prolog.org/pldoc/man?section=thread-signal][Signaling 
threads]] in the SWI-Prolog manual.
 
-** Top-level history
+** Top-level History
 :PROPERTIES:
 :CUSTOM_ID: top-level-history
 :DESCRIPTION: Accessing previous queries posted to the Prolog top-level
 :ALT_TITLE: Top-level History
 :END:
 
-=sweeprolog-top-level-mode= buffers provide a history of previously user
-inputs, similarly to other =comint-mode= derivatives such as =shell-mode=.
-To insert the last input from the history at the prompt, use =M-p=
-(=comint-previous-input=).  For a full description of history related
-commands, see [[info:emacs#Shell History][Shell History in the Emacs manual]].
+Sweep top-level buffers provide a history of previous user inputs,
+similarly to other ~comint-mode~ derivatives such as ~shell-mode~.  To
+insert the last input from the history at the prompt, use =M-p=
+(~comint-previous-input~).  For a full description of history related
+commands, see [[info:emacs#Shell History][Shell History]] in the Emacs manual.
 
 #+VINDEX: sweeprolog-top-level-min-history-length
+- User Option: sweeprolog-top-level-min-history-length :: Minimum
+  input length to record in the history of Sweep top-levels.
+#+VINDEX: sweeprolog-top-level-persistent-history
+- User Option: sweeprolog-top-level-persistent-history :: Controls if
+  and where Sweep top-level buffers persist their input history.
+
 The Sweep top-level history only records inputs whose length is at
-least =sweeprolog-top-level-min-history-length=.  This user option is set to
-3 by default, and should generally be set to at least 2 to keep the
-history from being clobbered with single-character inputs, which are
-common in the top-level interaction, e.g. =;= as used to invoke
+least ~sweeprolog-top-level-min-history-length~.  This user option is
+set to 3 by default, and should generally be set to at least 2 to keep
+the history from being clobbered with single-character inputs, which
+are common in the top-level interaction, e.g. ~;~ as used to invoke
 backtracking.
 
+Sweep can optionally persist top-level input history.  The user option
+~sweeprolog-top-level-persistent-history~ controls if and where
+top-levels store their history: when this option is non-~nil~, Sweep
+top-level buffers that you create read their input history from a
+persistent history file, and write their history back to it when you
+delete them.  If this option is a string, it is treated as a file
+name, and top-level buffers use that file to persistent their input
+history.  If it's a function, it is called with no arguments and
+should return a file name for the persistent history, or ~nil~ to
+disable persistent history for that top-level buffer.  The file name
+that this user option species can be either absolute or relative, in
+which case it is expanded relative to the default directory of the
+top-level buffer (see [[info:emacs#File Names][File Names]]).  This option can 
also be a list of
+the form ~(project REL DEF)~, in which case the persistent history
+file that a top-level buffer uses depends on the current project of
+the of that buffer (see [[info:emacs#Projects][Projects]] in the Emacs 
manual).  If there is no
+current project, the top-level persistent history file is ~DEF~.
+Otherwise, the history file is ~REL~ relative to the project's root
+directory.  You can leave ~DEF~ nil or omit it entirely to disable
+persistent history for top-levels that are not associated with any
+project.  By default, this option is set to ~nil~ which says not to
+keep persistent top-level history.
+
 ** Completion in the top-level
 :PROPERTIES:
 :CUSTOM_ID: completion-in-top-level
@@ -2446,13 +2475,13 @@ the user has the SWI-Prolog sources checked out locally.
 The way Sweep locates the SWI-Prolog sources depends on the user
 option ~sweeprolog-swipl-sources~.  When customized to a string, it is
 taken to be the path to the root directory of the SWI-Prolog source
-code.  If instead ~sweeprolog-swipl-sources~ is set to ~t~ (the default),
-Sweep will try to locate a local checkout of the SWI-Prolog sources
-automatically among known project root directories provided by Emacs's
-built-in ~project-known-project-roots~ from =project.el= (see 
[[info:emacs#Projects][Projects in
-the Emacs manual]] for more information about =project.el= projects).
-Lastly, setting ~sweeprolog-swipl-sources~ to ~nil~ disables searching for
-definitions of native built-ins.
+code.  If instead ~sweeprolog-swipl-sources~ is set to ~t~ (the
+default), Sweep will try to locate a local checkout of the SWI-Prolog
+sources automatically among known project root directories provided by
+Emacs's built-in ~project-known-project-roots~ from =project.el= (see
+[[info:emacs#Projects][Projects]] in the Emacs manual for more information 
about =project.el=
+projects).  Lastly, setting ~sweeprolog-swipl-sources~ to ~nil~
+disables searching for definitions of native built-ins.
 
 With ~sweeprolog-swipl-sources~ set, the provided commands for finding
 predicate definitions operate seamlessly on native built-ins to
@@ -2692,17 +2721,6 @@ some improvements remain to be pursued:
 
   And decide whether or not to apply the fragment.
 
-** Improvements around running Prolog
-:PROPERTIES:
-:CUSTOM_ID: todo-running
-:DESCRIPTION: List of potential enhancements for executing Prolog
-:ALT_TITLE: Running Improvements
-:END:
-
-- Persist top-level history across sessions :: Sweep should persist
-  Prolog top-level histories across invocations of
-  ~sweeprolog-top-level~, ideally also across different Emacs sessions.
-
 ** General improvements
 :PROPERTIES:
 :CUSTOM_ID: todo-general
diff --git a/sweeprolog.el b/sweeprolog.el
index d8cc7996e0..8793c7c805 100644
--- a/sweeprolog.el
+++ b/sweeprolog.el
@@ -449,6 +449,36 @@ completion candidates."
                            sweeprolog-predicate-non-hidden-p)
                  (function :tag "Custom exclusion predicate")))
 
+(defcustom sweeprolog-top-level-persistent-history nil
+  "Controls if and where top-level buffers store persistent history.
+
+If this option is nil, top-level buffers neither read persistent
+history on start-up nor write it on exit.  Otherwise, this option
+specifies a file name where top-level buffers store their input
+history.
+
+If this is a string FILE, top-level buffers use the file FILE for
+persistent history.  FILE can be either an absolute file name or
+a relative file name, in which case it is expanded relative to
+the `default-directory' of the top-level buffer.  If this is a
+function, it is called with no arguments to produce a string with
+the same meaning.
+
+This option can also be a list of the form (project REL DEF), in
+which case the persistent history file that a top-level buffer
+uses depends on the project that the buffer belongs to, as
+determined by `project-current'.  If the buffer belongs to a
+project, its persistent history file is REL relative to the
+project's root directory.  Otherwise, the persistent history file
+is DEF, which may be nil or omitted to disable persistent history
+for top-level buffers that don't belong to any project."
+  :package-version '((sweeprolog "0.20.0"))
+  :type '(choice (const    :tag "Disable persistent history" nil)
+                 (cons     :tag "File name relative to project root"
+                           (const project) string)
+                 (string   :tag "History file name")
+                 (function :tag "Function returning history file name")))
+
 ;;;; Keymaps
 
 (defvar sweeprolog-mode-map
@@ -2957,6 +2987,34 @@ Interactively, PROJ is the prefix argument."
         (sweeprolog--query-once "sweep" "sweep_colourise_query"
                                 (cons query (marker-position beg)))))))
 
+(defun sweeprolog-top-level-sentinel (proc msg)
+  "Sentinel for Prolog top-level processes.
+
+Calls `comint-write-input-ring' to update the top-level's
+persistent history before calling the default process sentinel
+function with PROC and MSG."
+  (comint-write-input-ring)
+  (internal-default-process-sentinel proc msg))
+
+(defun sweeprolog-top-level-setup-history (buf)
+  "Setup `comint-input-ring-file-name' for top-level buffer BUF."
+  (with-current-buffer buf
+    (setq-local comint-input-ring-file-name
+                (pcase sweeprolog-top-level-persistent-history
+                  ((pred stringp)
+                   sweeprolog-top-level-persistent-history)
+                  ((pred functionp)
+                   (funcall sweeprolog-top-level-persistent-history))
+                  (`(project . ,rel-def)
+                   (if-let ((project (project-current)))
+                       (expand-file-name (car rel-def)
+                                         (project-root project))
+                     (cadr rel-def)))))
+    (comint-read-input-ring t)
+    (set-process-sentinel (get-buffer-process buf)
+                          #'sweeprolog-top-level-sentinel)
+    (add-hook 'kill-buffer-hook #'comint-write-input-ring nil t)))
+
 (defun sweeprolog-top-level-buffer (&optional name)
   "Return a Prolog top-level buffer named NAME.
 
@@ -2980,6 +3038,7 @@ top-level."
                                    sweeprolog-prolog-server-port))
       (unless comint-last-prompt
         (accept-process-output (get-buffer-process buf) 1))
+      (sweeprolog-top-level-setup-history buf)
       (sweeprolog-top-level--populate-thread-id))
     buf))