From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matt Huszagh <huszaghmatt@gmail.com>
Subject: babel default header args as functions
Date: Fri, 07 Feb 2020 23:50:59 -0800
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To: "emacs-orgmode@gnu.org" <emacs-orgmode@gnu.org>

I've added the ability in my own configuration to use lambda functions
that evaluate to a string as babel default header arguments, instead of
just the plain strings currently allowed. Would anyone else be
interested in this feature? Shall I prepare a patch?

There are a number of use cases for this, but to give you an idea,
here's one I'm using myself.

  (setq org-babel-default-header-args:latex
        `((:file . (lambda ()
                     (concat "img/"
                             (sha1 (org-element-property :value (org-element-at-point)))
                             (by-backend '((html . "-html") (t . "-org")))
                             ".svg")))))

This computes a filename based on the hash of the block contents.

Matt