ox-publish: Change signature for preparation and completion functions

* doc/org.texi (Sources and destinations): Document new signature.
* lisp/ox-publish.el (org-publish-project-alist): Update docstring.
(org-publish-projects): Call preparation and
completion functions with the project properties as the sole argument.

`project-plist' used to be dynamically scoped.  This is no longer
possible due to the switch to lexical binding.

Reported-by: Arun Isaac <arunisaac@systemreboot.net>
<http://permalink.gmane.org/gmane.emacs.orgmode/107856>

doc/org.texi

@@ -14250,13 +14250,13 @@ use external tools to upload your website (@pxref{Uploading files}).
 @item @code{:preparation-function}
 @tab Function or list of functions to be called before starting the
 publishing process, for example, to run @code{make} for updating files to be
-published.  The project property list is scoped into this call as the
-variable @code{project-plist}.
+published.  Each preparation function is called with a single argument, the
+project property.
 @item @code{:completion-function}
 @tab Function or list of functions called after finishing the publishing
-process, for example, to change permissions of the resulting files.  The
-project property list is scoped into this call as the variable
-@code{project-plist}.
+process, for example, to change permissions of the resulting files.  Each
+completion function is called with a single argument, the project property
+list.
 @end multitable
 @noindent
 

etc/ORG-NEWS

@@ -104,10 +104,13 @@ is straightforward.  For example
 becomes
 
 : ("pdf" . (lambda (file link) (foo)))
-
 *** The ~{{{modification-time}}}~ macro can obtain time via =vc=
 The modification time will be determined via =vc.el= if the second
 argument is non-nil.  See the manual for details.
+*** Preparation and completion functions in publishing projects change signature
+Preparation and completion functions are now called with an argument,
+which is the project property list. It used to be dynamically scoped
+through the ~project-plist~ variable.
 ** New features
 *** New org-protocol key=value syntax
 

lisp/ox-publish.el

@@ -144,12 +144,16 @@ date.
   `:preparation-function'
 
     Function to be called before publishing this project.  This
-    may also be a list of functions.
+    may also be a list of functions.  Preparation functions are
+    called with the project properties list as their sole
+    argument.
 
   `:completion-function'
 
     Function to be called after publishing this project.  This
-    may also be a list of functions.
+    may also be a list of functions.  Completion functions are
+    called with the project properties list as their sole
+    argument.
 
 Some properties control details of the Org publishing process,
 and are equivalent to the corresponding user variables listed in
@@ -673,9 +677,9 @@ If `:auto-sitemap' is set, publish the sitemap too.  If
 `:makeindex' is set, also produce a file \"theindex.org\"."
   (dolist (project (org-publish-expand-projects projects))
     (let ((project-plist (cdr project)))
-      (let ((f (plist-get project-plist :preparation-function)))
-	(cond ((consp f) (mapc #'funcall f))
-	      ((functionp f) (funcall f))))
+      (let ((fun (plist-get project-plist :preparation-function)))
+	(cond ((consp fun) (dolist (f fun) (funcall f project-plist)))
+	      ((functionp fun) (funcall fun project-plist))))
       ;; Each project uses its own cache file.
       (org-publish-initialize-cache (car project))
       (when  (plist-get project-plist :auto-sitemap)
@@ -707,9 +711,9 @@ If `:auto-sitemap' is set, publish the sitemap too.  If
 	  (org-publish-index-generate-theindex
 	   project (plist-get project-plist :base-directory))
 	  (org-publish-file theindex project t)))
-      (let ((f (plist-get project-plist :completion-function)))
-	(cond ((consp f) (mapc #'funcall f))
-	      ((functionp f) (funcall f))))
+      (let ((fun (plist-get project-plist :completion-function)))
+	(cond ((consp fun) (dolist (f fun) (funcall f project-plist)))
+	      ((functionp fun) (funcall fun project-plist))))
       (org-publish-write-cache-file))))
 
 (defun org-publish-org-sitemap (project &optional sitemap-filename)