Suhail Shergill <suhailshergill@gmail.com> writes:

> running org-export-as-html on a subtree is currently problematic if the result
> is to be merged into a document which contains html-ized versions of other
> subtrees: the footnote references and definitions get clobbered.
>
> this patch uses the CUSTOM_ID property of the subtree to generate unique
> footnote references and definitions. if the subtree does not have the CUSTOM_ID
> property set the result is a nop.
>
>
> From 27f89f8bfff334810aba5c33af621e351fa0be79 Mon Sep 17 00:00:00 2001
> From: Suhail Shergill <suhailshergill@gmail.com>
> Date: Sun, 8 Apr 2012 10:49:51 -0400
> Subject: [PATCH] org-html.el: Make footnotes unique to an entry
>
> * lisp/org-html.el (org-export-as-html): Assign unique ids to footnotes
>   if possible
>
> If the entry (or its ancestor) has the CUSTOM_ID property defined, then
> use that as part of the generated footnote references and definitions.
> ---
>  lisp/org-html.el |   12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/lisp/org-html.el b/lisp/org-html.el
> index c9c9d78..8b79c39 100644
> --- a/lisp/org-html.el
> +++ b/lisp/org-html.el
> @@ -1248,6 +1248,9 @@ PUB-DIR is set, use this as the publishing directory."
>  	 (org-export-have-math nil)
>  	 (org-export-footnotes-seen nil)
>  	 (org-export-footnotes-data (org-footnote-all-labels 'with-defs))
> +	 (custom-id (or (org-entry-get nil "CUSTOM_ID" t) ""))
> +	 (footnote-def-prefix (format "fn-%s" custom-id))
> +	 (footnote-ref-prefix (format "fnr-%s" custom-id))
>  	 (lines
>  	  (org-split-string
>  	   (org-export-preprocess-string
> @@ -1685,8 +1688,8 @@ PUB-DIR is set, use this as the publishing directory."
>  			  (format
>  			   (concat "%s"
>  				   (format org-export-html-footnote-format
> -					   (concat "<a class=\"footref\" name=\"fnr.%s%s\" href=\"#fn.%s\">%s</a>")))
> -			   (or (match-string 1 org-line) "") n extra n n)
> +					   (concat "<a class=\"footref\" name=\"" footnote-ref-prefix ".%s%s\" href=\"#" footnote-def-prefix ".%s\">%s</a>")))
> +			   (or (match-string 1 line) "") n extra n n)
>  			  ;; If another footnote is following the
>  			  ;; current one, add a separator.
>  			  (if (save-match-data
> @@ -1773,8 +1776,9 @@ PUB-DIR is set, use this as the publishing directory."
>  			      (format
>  			       (concat "<p class=\"footnote\">"
>  				       (format org-export-html-footnote-format
> -					       "<a class=\"footnum\" name=\"fn.%s\" href=\"#fnr.%s\">%s</a>"))
> -			       n n n) t t org-line)))))
> +					       (concat
> +						"<a class=\"footnum\" name=\"" footnote-def-prefix ".%s\" href=\"#" footnote-ref-prefix ".%s\">%s</a>")))
> +			       n n n) t t line)))))
>  	    ;; Check if the line break needs to be conserved
>  	    (cond
>  	     ((string-match "\\\\\\\\[ \t]*$" org-line)
> -- 
> 1.7.10

-- 
Suhail