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

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

[Martin Steffen]

Hi,

I got a question whether the following is possible, when using
org-publish. Concretely I generate with org-publish markdown-files (that
ultimately are turned to HTML), but I guess the question is not specific
for this choice of a ``publication-process''.'


The whole content consists of quite a number of files, and in particular
has quite many html-links, and the links change (each year, each
semester) and they change in ``systematic ways''


What has been  for instance

   https://www.gitpages.io/somelecture/fall23/exercises

will have to be changed for the next round to

   https://www.gitpages.io/somelecture/fall24/exercises

(and there are links for many things beside exercises, and also they
have to be changed analogously).


The way I make that smooth is I define

#LINK: exercises-web https://www.gitpages.io/somelecture/fall23/exercises


and then, When the semester comes, replace all occurrences of fall23 to
fall24. Even if there are quite a number of such link definitions (for
all kind of information), it's straightforward. It's systematically
organized, and if all the link definitions are centralized in some file
collectionoflinks.org or similar that is #INCLUDE:-ed into all the
other files that work with this links, then ``porting'' of the whole
set-up to a new semester is quite easy and robust.

So I am happy with that, but I wonder if I could make it even more
parametrized. Like


      combining macros with links


like that "fall23" is an argument to a macros, which then builds up a
link. But that does not to work in a naive way, like


#+MACRO: semester fall24
#+LINK: https://www.gitpages.io/somelecture/{{{semester}}}/exercises


since macros do replacement in "text" (not in those #+-"meta-commands").

I tried parametrized macros_

#+MACRO: parametricexercizes  https://www.gitpages.io/somelecture/$1/exercises


and that half-way works. I.e., if I do

               parametricexercizes(fall24)  (*)

it works in that it results in a page with a correct link, but that's
not quite what I want, for 2 reasons. Really useful would the
parametrization if one could do

  parametricexercizes(semester)

where semester is a macro, not a literal "fall24". The second reason is
that the use as in (*) is not really useful, what I am  really after is
something like

       [[parametricexercizes(fall24)][the exercises are here]]

and the combination of macros inside [[ .... ]] does not work either.



Maybe there are other ways to achieve ``parametrization'' (or maybe not,
I have not worked much with macros in Org), any ideas?

best, Martin

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

[Fraga, Eric]

Hello,

I'm not entirely sure if I am missing something but, in case it helps,
macros can themselves invoke other macros and macros can make use of
[[target][desc]] syntax directly.  Can you not build up a hierarchy of
macros that would achieve what you want, along these lines:

--8<---------------cut here---------------start------------->8---
#+macro: link [[file:t.org][$1]]

#+macro: target {{{link($1)}}}

This is some text where I can look at {{{target(blah)}}}
--8<---------------cut here---------------end--------------->8---

HTH,
eric

-- 
: Eric S Fraga, with org release_9.6.19-1230-g407a55 in Emacs 30.0.50

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

[Martin Steffen]

>>>>> "Fraga," == Fraga, Eric <e.fraga@ucl.ac.uk> writes:

    Fraga,> Hello,

    Fraga,> I'm not entirely sure if I am missing something but, in case

thanks, it was more that I was missing something. I tried to combine
links and macros in a naive ways (without much studying the manual), so
I thought perhaps nesting is not possible (or there is another way).

Your suggestion solves my "problem" and makes the set-up a bit more
"parametric" and easier to adapt, without that one forgets some bits,
which is very nice.

best, Martin



    Fraga,> it helps, macros can themselves invoke other macros and
    Fraga,> macros can make use of [[target][desc]] syntax directly.
    Fraga,> Can you not build up a hierarchy of macros that would
    Fraga,> achieve what you want, along these lines:

    Fraga,> #+macro: link [[file:t.org][$1]]

    Fraga,> #+macro: target {{{link($1)}}}

    Fraga,> This is some text where I can look at {{{target(blah)}}}

    Fraga,> HTH, eric

    Fraga,> -- : Eric S Fraga, with org release_9.6.19-1230-g407a55 in
    Fraga,> Emacs 30.0.50

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

[Martin Steffen]

Hi,

maybe my email was premature. The combination of macros and links you
described is nice and useful for me (I did not much in the ways of
macros in org before). However, one aspect I am after seems not to work.

Your example was as follows, and it works:

--8<---------------cut here---------------start------------->8---
#+macro: link [[file:t.org][$1]]

#+macro: target {{{link($1)}}}

This is some text where I can look at {{{target(blah)}}}
--8<---------------cut here---------------end--------------->8---


There are 2 tweaks I had in mind in addition to your example, which
I can't get to work.

The first one is that the argument for the macro link should (also)
occur in the first part, a part of the link, not the text:

#+macro: source [[file:./$1/t.org][for the subdirectory  $1]]


That actually works, if one uses in the text

    {{{target(bla)}}}

that's great, but it leaves me replacing in the text many occurrences of
"bla" across many files.

The second tweak is that "bla" is a macro as well (centrally defined).
something like the following (modifing your example)

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

Then of I call the macros

1)   {{{source(24)}}}   : that works, $1 is replaced both times
                          and the link points to file:./24/t.org

2) {{{source({{{year}}})}}}: that does not work 
3) {{{target}}}            : that does not work either


In both cases 2) and 3), the result of the macro expansion is the following (I
export to markdown)


    [for the year 24](./{{{year}}}/t.md)

-   [for the year 24](./{{{year}}}/t.md)

i.e, the argument  (intended to be 24) is properly replaced in ``text
part'' but not in the `` link'' part.


I don't know if I simply expect ``too much'' from the macro-expansion
facilities.... best, Martin




>>>>> "Martin" == Martin Steffen <msteffen@ifi.uio.no> writes:

>>>>> "Fraga," == Fraga, Eric <e.fraga@ucl.ac.uk> writes:

    Martin>     Fraga,> Hello,

    Martin>     Fraga,> I'm not entirely sure if I am missing something
    Martin> but, in case

    Martin> thanks, it was more that I was missing something. I tried to
    Martin> combine links and macros in a naive ways (without much
    Martin> studying the manual), so I thought perhaps nesting is not
    Martin> possible (or there is another way).

    Martin> Your suggestion solves my "problem" and makes the set-up a
    Martin> bit more "parametric" and easier to adapt, without that one
    Martin> forgets some bits, which is very nice.

    Martin> best, Martin



    Martin>     Fraga,> it helps, macros can themselves invoke other
    Martin> macros and Fraga,> macros can make use of [[target][desc]]
    Martin> syntax directly.  Fraga,> Can you not build up a hierarchy
    Martin> of macros that would Fraga,> achieve what you want, along
    Martin> these lines:

    Martin>     Fraga,> #+macro: link [[file:t.org][$1]]

    Martin>     Fraga,> #+macro: target {{{link($1)}}}

    Martin>     Fraga,> This is some text where I can look at
    Martin> {{{target(blah)}}}

    Martin>     Fraga,> HTH, eric

    Martin>     Fraga,> -- : Eric S Fraga, with org
    Martin> release_9.6.19-1230-g407a55 in Fraga,> Emacs 30.0.50

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

[Fraga, Eric]

On Thursday, 30 May 2024 at 07:03, Martin Steffen wrote:
> [...]
> #+macro: target {{{source({{{year}}})}}}

So, the problem you are running into is that you cannot evaluate a macro
with arguments that require evaluating a macro.  Unless you can change
the order in which you evaluate these macros, the only solution I can
suggest is that you define elisp macros.  See the info manual,
specifically the second example in the macro replacement section.

#+macro: complicated (eval ...)

-- 
: Eric S Fraga, with org release_9.6.19-1230-g407a55 in Emacs 30.0.50

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

[Martin Steffen]

>>>>> "Fraga," == Fraga, Eric <e.fraga@ucl.ac.uk> writes:

    Fraga,> On Thursday, 30 May 2024 at 07:03, Martin Steffen wrote:
    >> [...]  #+macro: target {{{source({{{year}}})}}}

    Fraga,> So, the problem you are running into is that you cannot
    Fraga,> evaluate a macro with arguments that require evaluating a
    Fraga,> macro.  Unless you can change the order in which you
    Fraga,> evaluate these macros, the only solution I can suggest is
    Fraga,> that you define elisp macros.  See the info manual,
    Fraga,> specifically the second example in the macro replacement
    Fraga,> section.

thanks, fair enough, I look into the elisp-option. Martin




    Fraga,> #+macro: complicated (eval ...)

    Fraga,> -- : Eric S Fraga, with org release_9.6.19-1230-g407a55 in
    Fraga,> Emacs 30.0.50

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

[Max Nikulin]

On 30/05/2024 12:03, Martin Steffen wrote:
> #+macro: year 24
> #+macro: source [[file:./$1/t.org][for the year $1]]
> #+macro: target {{{source({{{year}}})}}}

Custom link type might be more convenient

(info "(org) Adding Hyperlink Types")
https://orgmode.org/manual/Adding-Hyperlink-Types.html

I can not figure out if it is possible with some trick to expand 
{{{year}}} before file:... is parsed.

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

[Ihor Radchenko]

Max Nikulin <manikulin@gmail.com> 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.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>

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

[Max Nikulin]

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.

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

[Ihor Radchenko]

Martin Steffen <msteffen@ifi.uio.no> writes:

> The way I make that smooth is I define
>
> #LINK: exercises-web https://www.gitpages.io/somelecture/fall23/exercises
>
> ...
> So I am happy with that, but I wonder if I could make it even more
> parametrized. Like
>
>
>       combining macros with links
>
>
> like that "fall23" is an argument to a macros, which then builds up a
> link. But that does not to work in a naive way, like
>
>
> #+MACRO: semester fall24
> #+LINK: https://www.gitpages.io/somelecture/{{{semester}}}/exercises
> ...
> where semester is a macro, not a literal "fall24". The second reason is
> that the use as in (*) is not really useful, what I am  really after is
> something like
>
>        [[parametricexercizes(fall24)][the exercises are here]]

The simplest thing you can use is

#+LINK: exercises-web https://www.gitpages.io/somelecture/%s/exercises

[[exercises-web:fall24][the exercises are here]]

If you need something more complex, check out %(my-function) placeholder
instead of %s as described in "Link Abbreviations" section of Org manual.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>