Hello,

I have been playing with using embedded calc equations in org mode.  I
have tried filters and with org emphasis markers but finally have come
around to using the new org link capabilities.  Thank you John for
these!

I've defined the following:

#+begin_src emacs-lisp
  (org-link-set-parameters
   "calc"
   :export (lambda (path desc backend)
             (cond
              ((eq 'latex backend)
               (format "\\texttt{%s}" desc))))
   :face '(:foreground "chartreuse"))
#+end_src 

which I then use like this:

#+begin_src org
  [[calc:][Pv := 10^(6.886 - 1175.817 / (100 + 224.867)) => 1847.653]]
#+end_src

and with appropriate settings for calc [1], calc can manipulate and
evaluate the expressions.  So far, so good.

Two minor issues:

1. the fontification doesn't colour the links in the colour I would like
   (chartreuse, #7fff00).

2. if I have two expressions close enough, both with := and =>
   operators, org seems to get confused and interprets two of the =
   symbols, each from one expression, as emphasis markers, as in this
   example:

   #+begin_src org
     [[calc:][y := 3 x - 5 => 55]] [[calc:][z := sqrt(y) => 7.416]]
   #+end_src

Screenshot attached showing both problems: colour and second = sign
disappearing in first link and first = sign in second link.

Any suggestions on how to improve/fix these aspects?  Both are minor
presentation issues and everything else is working very well.  Calc
allows me to work with these expressions easily in org now!

Many thanks,
eric


Footnotes: 
[1]  Settings using calc: links:

     #+begin_src emacs-lisp
       (defun esf/org-mode-calc-settings ()
         (setq calc-embedded-open-formula "\\[\\[calc:]\\["
               calc-embedded-open-new-formula "[[calc:]["
               calc-embedded-close-formula "]]"
               calc-embedded-close-new-formula "]]"))
       (add-hook 'org-mode-hook #'esf/org-mode-calc-settings)
     #+end_src 

-- 
: Eric S Fraga (0xFFFCF67D), Emacs 26.0.50.1, Org release_9.0.5-370-g9f3a02.dirty