From 371a3294887cdb714aff14494c5286a19524c807 Mon Sep 17 00:00:00 2001
From: Nicolas Goaziou <mail@nicolasgoaziou.fr>
Date: Sat, 15 Feb 2020 17:31:34 +0100
Subject: [PATCH 2/2] ol: Extend open tooling in link parameters

* lisp/ol.el (org-link-parameters): Add :open parameter.
(org-link-open): Call custom-link functions after internal ones.
(org-link-open-as-file): New function.
(org-link-parameters): Reference new function.
(org-link-open): Use new function.
---
 lisp/ol.el | 75 +++++++++++++++++++++++++++++++-----------------------
 1 file changed, 43 insertions(+), 32 deletions(-)

diff --git a/lisp/ol.el b/lisp/ol.el
index f850a5313..710947c92 100644
--- a/lisp/ol.el
+++ b/lisp/ol.el
@@ -93,13 +93,21 @@ Subsequent optional elements make up a property list for that
 type.
 
 All properties ar optional.  However, the most important ones
-are, in this order, `:follow', `:export', and `:store', described
-below.
+are, in this order, `:open' (or `:follow'), `:export', and
+`:store', described below.
 
+`:open'
 `:follow'
 
-  Function that takes the link path (a string) as an argument and
-  \"opens\" the link.
+  Function used to follow the link, when `org-open-at-point' is
+  command runs on it.
+
+  The function stored in `:open' is called with two arguments:
+  the path, as a string, and a universal prefix argument, whereas
+  the one stored in `:follow' is called with the path only.
+
+  You may use `org-link-open-as-file' helper function for types
+  similar to \"file\".
 
 `:export'
 
@@ -990,37 +998,14 @@ for internal and \"file\" links, or stored as a parameter in
   (let ((type (org-element-property :type link))
 	(path (org-element-property :path link)))
     (cond
+     ;; Opening a "file" link requires special treatment since we
+     ;; first need to integrate search option, if any.
      ((member type '("file" "attachment"))
       (when (string= type "attachment")
 	(setq path (org-attach-link-expand link)))
-      (if (string-match "[*?{]" (file-name-nondirectory path))
-	  (dired path)
-	;; Look into `org-link-parameters' in order to find
-	;; a DEDICATED-FUNCTION to open file.  The function will be
-	;; applied on raw link instead of parsed link due to the
-	;; limitation in `org-add-link-type' ("open" function called
-	;; with a single argument).  If no such function is found,
-	;; fallback to `org-open-file'.
-	(let* ((option (org-element-property :search-option link))
-	       (app (org-element-property :application link))
-	       (dedicated-function
-		(org-link-get-parameter (if app (concat type "+" app) type)
-					:follow)))
-	  (if dedicated-function
-	      (funcall dedicated-function
-		       (concat path
-			       (and option (concat "::" option))))
-	    (apply #'org-open-file
-		   path
-		   (cond (arg)
-			 ((equal app "emacs") 'emacs)
-			 ((equal app "sys") 'system))
-		   (cond ((not option) nil)
-			 ((string-match-p "\\`[0-9]+\\'" option)
-			  (list (string-to-number option)))
-			 (t (list nil option))))))))
-     ((functionp (org-link-get-parameter type :follow))
-      (funcall (org-link-get-parameter type :follow) path))
+      (let* ((option (org-element-property :search-option link))
+	     (path (if option (concat path "::" option) path)))
+	(org-link-open-as-file path arg)))
      ((member type '("coderef" "custom-id" "fuzzy" "radio"))
       (unless (run-hook-with-args-until-success 'org-open-link-functions path)
 	(if (not arg) (org-mark-ring-push)
@@ -1042,6 +1027,10 @@ for internal and \"file\" links, or stored as a parameter in
 		       (>= (point-max) destination))
 	    (widen))
 	  (goto-char destination))))
+     ((functionp (org-link-get-parameter type :open))
+      (funcall (org-link-get-parameter type :open) path arg))
+     ((functionp (org-link-get-parameter type :follow))
+      (funcall (org-link-get-parameter type :follow) path))
      (t (browse-url-at-point)))))
 
 (defun org-link-open-from-string (s &optional arg)
@@ -1240,6 +1229,28 @@ of matched result, which is either `dedicated' or `fuzzy'."
 				    (reverse slines))) "\n")))))
     (mapconcat #'identity (split-string s) " ")))
 
+(defun org-link-open-as-file (path arg)
+  "Pretend PATH is a file name and open it.
+
+According to \"file\"-link syntax, PATH may include addition
+search options, separated from the file name with \"::\".
+
+This function is meant to be used as a possible tool for `:open'
+property in `org-link-parameters.'"
+  (if (string-match "[*?{]" (file-name-nondirectory path))
+      (dired path)
+    (let* ((option (and (string-match "::\\(.*\\)\\'" path)
+			(match-string 1 path)))
+	   (path (if (not option) path
+		   (substring path 0 (match-beginning 0)))))
+      (apply #'org-open-file
+	     path
+	     arg
+	     (cond ((not option) nil)
+		   ((string-match-p "\\`[0-9]+\\'" option)
+		    (list (string-to-number option)))
+		   (t (list nil option)))))))
+
 (defun org-link-display-format (s)
   "Replace links in string S with their description.
 If there is no description, use the link target."
-- 
2.25.0