From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rasmus <rasmus@gmx.us>
Subject: Re: TIL about use of eval in user Org macros.. Documentation?
Date: Thu, 21 Dec 2017 10:45:38 +0100
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Kaushal Modi <kaushal.modi@gmail.com> writes:

> Hello,
>
> The commit message in this commit is golden:
> http://orgmode.org/cgit.cgi/org-mode.git/commit/?id=3ac619c8ac9934a2a1368f3de8ffad951f900067
>
> Using that info, I came up with a "classified" version of n macro for markdown/HTML:
>
> #+MACRO: sec (eval (concat "<span class=\"section-num\">" (number-to-string (org-macro--counter-increment $1 $2)) "</span>"))
>
> Based on that I have two questions:

> 1. Can you please document the use of eval form in Org macro definitions
> in the Org manual(.org)? Its awesome wasn't evident to me until I read
> that commit message.

I guess it isn’t documented in the manual...

I agree, there could be a second example and the mention of using lisp or
at least a mention of the ‘org-export-global-macros’ docstring.

> 2. (Another question on canonical approach) What would be the recommended approach for an exporter backend to add new
> macros or override existing macros (like "n" macro to wrap the string with HTML class as an example)? Should it update
> org-macro-templates in org-export-before-processing-hook? or something similar?

Do you really need to overwrite an old macro?  Couldn’t you define a new
macro?  org-export-before-processing-hook is definitely the right hook,
cf. ‘org-export-as’.

   (defun fooreplace (backend)
	(when (eq backend 'mybackend)
	  (goto-char (point-min))
	  (while (search-forward-regexp "{{{foo\\((?\\)" nil t)
	    (replace-match "{{{myfoo\\1"))
	  (goto-char (point-max))
	  (insert "\n#+macro: myfoo mybar\n"))))

Rasmus

-- 
May contains speling mistake