Re: question about links, macros + org-publish and "parametrization"

[Max Nikulin <manikulin@gmail.com>]

On 30/05/2024 23:33, Ihor Radchenko wrote:
> Max Nikulin writes:
> 
>> I can not figure out if it is possible with some trick to expand
>> {{{year}}} before file:... is parsed.
> 
> Not possible. Macros are not recognized in verbatim contexts like link
> path.

I had in mind some technique like \expandafter in TeX or intermediate 
macro in the case of C preprocessor.

---- 8< ----
#+macro: mend }}}
#+macro: year 24
#+macro: source [[file:./$1/t.org][for the year $1]]
#+macro: target {{{source({{{year}}}){{{mend}}}

{{{source(24)}}}
{{{target}}}
{{{source({{{year}}}){{{mend}}}
---- >8 ----

It signals

     (error "Undefined Org macro: source; aborting")

during processing source code blocks. Export buffer content at this step:
---- 8< ----
#+macro: mend }}}
#+macro: year 24
#+macro: source [[file:./$1/t.org][for the year $1]]
#+macro: target {{{source({{{year}}}){{{mend}}}

[[file:./24/t.org][for the year 24]]
{{{source(24)}}}
{{{source(24)}}}
---- >8 ----

So I have almost achieved the goal despite the approach is rather 
fragile. I might work with additional pass of macro processing added as 
an extra export filter.

However I believe it is better to use either a custom link type or an 
eval macro instead of set of kludges with postponing expansion.

It is not intuitive that macro parameters are not eagerly expanded like 
function arguments in most common procedural programming languages. 
Macro languages have their own shortcomings.