gnuplot is able to generate graphs, but needs much more work

lisp/langs/org-babel-gnuplot.el

@@ -41,12 +41,68 @@
 
 (add-to-list 'org-babel-tangle-langs '("gnuplot" "gnuplot"))
 
+(defvar org-babel-default-header-args:gnuplot '((:results . "file"))
+  "Default arguments to use when evaluating a gnuplot source block.")
+
+(defvar org-babel-gnuplot-timestamp-fmt nil)
+
 (defun org-babel-execute:gnuplot (body params)
   "Execute a block of Gnuplot code with org-babel.  This function is
 called by `org-babel-execute-src-block'."
-  (message "executing Gnuplot source code block"))
+  (message "executing Gnuplot source code block")
+  (let* ((vars (org-babel-ref-variables params))
+         (result-params (split-string (or (cdr (assoc :results params)) "")))
+         (out-file (cdr (assoc :file params)))
+         (cmdline (cdr (assoc :cmdline params)))
+         (in-file (make-temp-file "org-babel-ditaa")))
+    ;; insert variables into code body
+    (mapc
+     (lambda (pair)
+       (message "resolving %S" pair) ;; debugging
+       (setq body
+             (replace-regexp-in-string
+              (regexp-quote (format "%s" (car pair)))
+              (if (listp (cdr pair))
+                  (org-babel-gnuplot-table-to-data
+                   (cdr pair) (make-temp-file "org-babel-gnuplot") params)
+                (cdr pair)) body)))
+     vars)
+    (with-temp-buffer ;; evaluate the code body with gnuplot
+      (insert (concat body "\n"))
+      (gnuplot-mode)
+      (gnuplot-send-buffer-to-gnuplot))
+    out-file))
 
 (defun org-babel-prep-session:gnuplot (session params))
 
+(defun org-babel-gnuplot-quote-timestamp-field (s)
+  "Convert field S from timestamp to Unix time and export to gnuplot."
+  (format-time-string org-babel-gnuplot-timestamp-fmt (org-time-string-to-time s)))
+
+(defun org-babel-gnuplot-quote-tsv-field (s)
+  "Quote field S for export to gnuplot."
+  (unless (stringp s)
+    (setq s (format "%s" s)))
+  (if (string-match org-table-number-regexp s) s
+    (if (string-match org-ts-regexp3 s)
+	(org-babel-gnuplot-quote-timestamp-field s)
+      (concat "\"" (mapconcat 'identity (split-string s "\"") "\"\"") "\""))))
+
+(defun org-babel-gnuplot-table-to-data (table data-file params)
+  "Export TABLE to DATA-FILE in a format readable by gnuplot.
+Pass PARAMS through to `orgtbl-to-generic' when exporting TABLE."
+  (with-temp-file data-file
+    (message "table = %S" table)
+    (make-local-variable 'org-babel-gnuplot-timestamp-fmt)
+    (setq org-babel-gnuplot-timestamp-fmt (or
+                                           (plist-get params :timefmt)
+                                           "%Y-%m-%d-%H:%M:%S"))
+    (insert (orgtbl-to-generic
+	     table
+	     (org-combine-plists
+	      '(:sep "\t" :fmt org-babel-gnuplot-quote-tsv-field)
+	      params))))
+  data-file)
+
 (provide 'org-babel-gnuplot)
 ;;; org-babel-gnuplot.el ends here

org-babel.org

@@ -1982,13 +1982,37 @@ This could probably be added to [[file:lisp/org-babel-script.el][org-babel-scrip
 *** STARTED gnuplot
 (see [[* file result types][file result types]])
 
-- a required =file= header argument
+- a =file= header argument
 - a =cmdline= header argument
 - to add variables
   - scalar variables should be replaced in the body of the gnuplot code
   - vector variables should be exported to tab-separated files, and
     the variable names should be replaced with the path to the files
 
+#+PLOT: title:"Citas" ind:1 deps:(3) type:2d with:histograms set:"yrange [0:]"
+#+TBLNAME: gnuplot-data
+| independent var | first dependent var | second dependent var |
+|-----------------+---------------------+----------------------|
+|             0.1 |               0.425 |                0.375 |
+|             0.2 |              0.3125 |               0.3375 |
+|             0.3 |          0.24999993 |           0.28333338 |
+|             0.4 |               0.275 |              0.28125 |
+|             0.5 |                0.26 |                 0.27 |
+|             0.6 |          0.25833338 |           0.24999993 |
+|             0.7 |          0.24642845 |           0.23928553 |
+|             0.8 |             0.23125 |               0.2375 |
+|             0.9 |          0.23333323 |            0.2333332 |
+|               1 |              0.2225 |                 0.22 |
+|             1.1 |          0.20909075 |           0.22272708 |
+|             1.2 |          0.19999998 |           0.21458333 |
+|             1.3 |          0.19615368 |           0.21730748 |
+
+#+srcname: implementing-gnuplot
+#+begin_src gnuplot :var data=gnuplot-data
+set title "Implementing Gnuplot"
+plot "data" using 1:2 with lines
+#+end_src
+
 *** TODO dot
 (see [[* file result types][file result types]])