[elpa] scratch/ediprolog e75c0ddfc4 30/31: Merge Jun 8 2020 commit '751119cfee9' into externals/ediprolog

[Stefan Monnier]

branch: scratch/ediprolog
commit e75c0ddfc47f968a4e227f83421abc963287ad12
Merge: 3fa2be14ea 751119cfee
Author: Stefan Monnier <monnier@iro.umontreal.ca>
Commit: Stefan Monnier <monnier@iro.umontreal.ca>

    Merge Jun 8 2020 commit '751119cfee9' into externals/ediprolog
    
    This seems to be the commit in the upstream repository that most closely
    matches the commit in the elpa.git.
---
 README.md     | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ediprolog.el  |   4 +--
 factorial.png | Bin 0 -> 60804 bytes
 3 files changed, 103 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
new file mode 100644
index 0000000000..406a356fd1
--- /dev/null
+++ b/README.md
@@ -0,0 +1,101 @@
+# Introduction
+
+*ediprolog* lets you interact with Prolog in all Emacs buffers.
+You can consult Prolog programs and evaluate embedded queries.
+
+**Project page**:
+
+[**https://www.metalevel.at/ediprolog/**](https://www.metalevel.at/ediprolog/)
+
+**Video**:
+
+[https://www.metalevel.at/prolog/videos/ediprolog](https://www.metalevel.at/prolog/videos/ediprolog)
+
+See also [PceProlog](https://www.metalevel.at/pceprolog/).
+
+# Installation
+
+With Emacs&ge;24.1, the simplest way to install ediprolog is to use
+Emacs's built-in *package&nbsp;manager* via the key sequence:
+
+    M-x package-install RET ediprolog RET
+
+Alternatively, copy [ediprolog.el](ediprolog.el) to your `load-path`
+and add the following form to your `.emacs`, then evaluate the form or
+restart&nbsp;Emacs:
+
+    (require 'ediprolog)
+
+After you have installed ediprolog, you can customize it with:
+
+    M-x customize-group RET ediprolog RET
+
+The two most important configuration options are:
+
+   - `ediprolog-system`, either `scryer` or `swi`
+   - `ediprolog-program`, the path of the Prolog executable.
+
+# Usage
+
+The central function is `ediprolog-dwim` (Do What I Mean). I recommend
+to bind it to the function&nbsp;key&nbsp;F10 by adding the following
+form to your&nbsp;`.emacs` and evaluating it:
+
+    (global-set-key [f10] 'ediprolog-dwim)
+
+In the following, I assume that you have also done this.
+
+Depending on the content at point, `ediprolog-dwim` does the
+"appropriate" thing: If point is on a *query*, it sends the query to a
+Prolog process, and you interact with the process in the current
+buffer as on a terminal. Queries start with "?-" or ":-", possibly
+preceded by "%" and whitespace. An example of a query is:
+
+    %?- member(X, [a,b,c]).
+
+If you press F10 when point is on that query, you get:
+
+    %?- member(X, [a,b,c]).
+    %@    X = a
+    %@ ;  X = b
+    %@ ;  X = c
+    %@ ;  false.
+
+When waiting for output of the Prolog process, you can press C-g to
+unblock Emacs and continue with other work. To resume interaction
+with the Prolog process, use **M-x&nbsp;ediprolog-toplevel&nbsp;RET**.
+
+If you press F10 when point is *not* on a query, the buffer content is
+consulted in the Prolog process, and point is moved to the first error
+(if any). You do&nbsp;*not* need to *save* the file beforehand, since
+the *buffer&nbsp;content* (not the file) is consulted.
+
+For convenience, the most recent interactions with the Prolog
+process are logged in the buffer `*ediprolog-history*`.
+
+Use **M-x ediprolog-localize RET** to make any Prolog process started
+in the current buffer buffer-local. This way, you can run distinct
+processes simultaneously. Revert with
+**M-x&nbsp;ediprolog-unlocalize&nbsp;RET**.
+
+`ediprolog-dwim` with prefix arguments has special meanings:
+
+| Key Sequence |   Meaning                                                |
+|--------------|----------------------------------------------------------|
+|  C-0 F10     |   kill Prolog process                                    |
+|  C-1 F10     |   always consult buffer (even when point is on a query)  |
+|  C-2 F10     |   always consult buffer, using a new process             |
+|  C-7 F10     |   equivalent to `ediprolog-toplevel'                     |
+|  C-u F10     |   first consult buffer, then evaluate query (if any)     |
+|  C-u C-u F10 |   like C-u F10, with a new process                       |
+
+Tested with Scryer Prolog 0.8.119 and SWI-Prolog 8.1.24, using Emacs
+versions 26.1 and&nbsp;27.0.50.
+
+# Screenshot
+
+Here is a sample interaction, using
+[CLP(FD)&nbsp;constraints](https://www.metalevel.at/prolog/clpfd) to
+relate a number to its factorial:
+
+![Factorial](factorial.png)
diff --git a/ediprolog.el b/ediprolog.el
index d88d30e80c..503643ddab 100644
--- a/ediprolog.el
+++ b/ediprolog.el
@@ -1,6 +1,6 @@
 ;;; ediprolog.el --- Emacs Does Interactive Prolog
 
-;; Copyright (C) 2006-2009, 2012-2013, 2016-2017, 2020  Free Software 
Foundation, Inc.
+;; Copyright (C) 2006-2022  Free Software Foundation, Inc.
 
 ;; Author: Markus Triska <triska@metalevel.at>
 ;; Keywords: languages, processes
@@ -69,7 +69,7 @@
 
 ;; If you press F10 when point is *not* on a query, the buffer content
 ;; is consulted in the Prolog process, and point is moved to the first
-;; error (if any).  In transient mark mode, if the region is active,
+;; error (if any). In transient mark mode, if the region is active,
 ;; only the text in the region is consulted.
 
 ;; For convenience, the most recent interactions with the Prolog
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