Re: Org src blocks and multiline macros

["Berry, Charles" <ccberry@ucsd.edu>]

> On Aug 2, 2018, at 5:32 AM, Jarmo Hurri <jarmo.hurri@iki.fi> wrote:
> 
<Kaushal Modi replying here>
>> 
>> Org macros don't get evaluated inside src blocks as far as I know. But
>> Noweb might help you. Look for this feature in Org manual. I use Noweb as
>> "macros for src blocks".
> 

Me, too. But maybe Jarmo just wants a template for some text element. ??

> Yep, that will give me something similar:
> 
> #+name: val1
> #+BEGIN_SRC org :exports none
> foo
> #+END_SRC
> 
> #+name: val2
> #+BEGIN_SRC org :exports none
> bar
> #+END_SRC
> 
> #+BEGIN_SRC org :noweb yes
>  Currently this gives me ~<<val1>><<val2>>~ indeed!
> #+END_SRC
> 
> Compared to multiline macros, though, having to (re)define bunch of src
> blocks for variables does seem like an overkill.
> 
> BTW, does anyone know how I could enforce the standard
> Org-interpretation of '~' in the resulting, exported Org.
> 
> Jarmo

There are some limitations on noweb expansion. C-c C-v C-v in a src block will show you what the expansion looks like and how :var args are handled.

ob-org does not provide for variables AFAICS. But using emacs-lisp with a :results drawer to render the output as org should help:


--8<---------------cut here---------------start------------->8---
#+header: :results drawer :exports results
#+begin_src emacs-lisp :var val1="foo" :var val2="bar" 
   (concat "Currently this gives me ~" val1 val2 "~ indeed!")
#+END_SRC

#+RESULTS:
:results:
Currently this gives me ~foobar~ indeed!
:end:
--8<---------------cut here---------------end--------------->8---


BTW, if you really do need a long or multiline MACRO, there is the possibility of using an `eval' style macro with a custom elisp function. e.g.

#+MACRO: longish-macro (eval (my-really-long-macro-def $1 $2 $3))

See

(info "(org) Macro Replacement")

But this carries the burden of having to defun `my-really-long-macro-def' before exporting your document.
 
HTH,

Chuck