From fc1ecf42cd8d0d27cda98ced2c2be365ad305df7 Mon Sep 17 00:00:00 2001
From: TEC <tec@tecosaur.com>
Date: Thu, 9 Jul 2020 04:27:18 +0800
Subject: [PATCH 04/11] org-plot.el: abstract plot types into custom var

* lisp/org-plot.el (org-plot/gnuplot-script): Abstract the generation of
gnuplot commands from the three hardcoded types: 2d, 3d, and grid.
A new custom variable `org-plot/preset-plot-types' is defined to declare
plot types and provide a lambda which is called with a fixed signature
to generate associated gnuplot code.  The previously hardcoded types are
implemented as the default value.

By extracting these types to a custom variable, users are able to create
their own presets for frequently used setups. Note that while this moves
the most significant hardcoding of the 2d, 3d, and grid types in
`org-plot/gnuplot-script', there are still a few minor fragments that I
am not sure how to best address --- yet.
---
 lisp/org-plot.el | 71 ++++++++++++++++++++++++++++++++----------------
 1 file changed, 48 insertions(+), 23 deletions(-)

diff --git a/lisp/org-plot.el b/lisp/org-plot.el
index f8db45273..207f5d4af 100644
--- a/lisp/org-plot.el
+++ b/lisp/org-plot.el
@@ -188,6 +188,49 @@ other content generated in `org-plot/gnuplot-script'."
   :group 'org-plot
   :type '(choice string function))
 
+(defcustom org-plot/preset-plot-types
+  '((2d (lambda (data-file num-cols params plot-str)
+	  (let* ((type (plist-get params :plot-type))
+		 (with (if (eq type 'grid) 'pm3d (plist-get params :with)))
+		 (ind (plist-get params :ind))
+		 (deps (if (plist-member params :deps) (plist-get params :deps)))
+		 (text-ind (plist-get params :textind))
+		 (col-labels (plist-get params :labels))
+		 res)
+	    (dotimes (col num-cols res)
+	      (unless (and (eq type '2d)
+			   (or (and ind (equal (1+ col) ind))
+			       (and deps (not (member (1+ col) deps)))))
+		(setf res
+		      (cons
+		       (format plot-str data-file
+			       (or (and ind (> ind 0)
+					(not text-ind)
+					(format "%d:" ind)) "")
+			       (1+ col)
+			       (if text-ind (format ":xticlabel(%d)" ind) "")
+			       with
+			       (or (nth col col-labels)
+				   (format "%d" (1+ col))))
+		       res)))))))
+    (3d (lambda (data-file num-cols params plot-str)
+	  (let* ((type (plist-get params :plot-type))
+		 (with (if (eq type 'grid) 'pm3d (plist-get params :with))))
+	    (list (format "'%s' matrix with %s title ''"
+			  data-file with)))))
+    (grid (lambda (data-file num-cols params plot-str)
+	    (let* ((type (plist-get params :plot-type))
+		   (with (if (eq type 'grid) 'pm3d (plist-get params :with))))
+	    (list (format "'%s' with %s title ''"
+			  data-file with))))))
+  "List of plot presets with the type name as the car, and a function
+which yeilds plot-lines (a list of strings) as the cdr.
+The parameters of `org-plot/gnuplot-script' and PLOT-STR are passed to
+that function. i.e. it is called with the following arguments:
+  DATA-FILE NUM-COLS PARAMS PLOT-STR"
+  :group 'org-plot
+  :type '(alist :value-type (symbol group)))
+
 (defun org-plot/gnuplot-script (data-file num-cols params &optional preface)
   "Write a gnuplot script to DATA-FILE respecting the options set in PARAMS.
 NUM-COLS controls the number of columns plotted in a 2-d plot.
@@ -254,29 +297,11 @@ manner suitable for prepending to a user-specified script."
 			   (or timefmt	; timefmt passed to gnuplot
 			       "%Y-%m-%d-%H:%M:%S") "\"")))
     (unless preface
-      (pcase type			; plot command
-	(`2d (dotimes (col num-cols)
-	       (unless (and (eq type '2d)
-			    (or (and ind (equal (1+ col) ind))
-				(and deps (not (member (1+ col) deps)))))
-		 (setf plot-lines
-		       (cons
-			(format plot-str data-file
-				(or (and ind (> ind 0)
-					 (not text-ind)
-					 (format "%d:" ind)) "")
-				(1+ col)
-				(if text-ind (format ":xticlabel(%d)" ind) "")
-				with
-				(or (nth col col-labels)
-				    (format "%d" (1+ col))))
-			plot-lines)))))
-	(`3d
-	 (setq plot-lines (list (format "'%s' matrix with %s title ''"
-					data-file with))))
-	(`grid
-	 (setq plot-lines (list (format "'%s' with %s title ''"
-					data-file with)))))
+      (let ((type-func (cadr (assoc type org-plot/preset-plot-types))))
+	(when type-func
+	  (setq plot-lines
+		(funcall type-func data-file num-cols params plot-str))))
+
       (funcall ats
 	       (concat plot-cmd " " (mapconcat #'identity
 					       (reverse plot-lines)
-- 
2.28.0