pandoc custom template condition: looking for variable with certain value (yaml metadata)

[Jan Kröger]

Hi,

as long as I understood, it is possible to set a pandoc template condition
which asks if a variable's value is not zero.
But want I need is to create a condition which asks for a variable with a
certain value.
Is that possible?

An example: I want pandoc to write some yaml metadata (contributors names)
to the epub's titlepage to give the different contributors their
credentials (put a label in front of the name).

I have set them in yaml metadata block like:
contributor:
- role: edt
text: Person1
- role: pfr
text: Person2
- role: pht
text: Person3
- role: trl
text:

What works is a simple list of different contributors, set in my custom
template:
$for(contributor)$
$contributor.text$$sep$,
$endfor$

so with:
pandoc metadata.yaml book-content.md -t epub3 -o book.epub

I got a list of all contributors written to the title page:
Person1, Person2, Person3

But what I want instead is this:
Editor: Person1
Proofreader: Person2
Photographer: Person3

So what I am missing is the possibility to set e.g.:
$for(contributor)$
$if(contributor.role)==edt$
<p>Editor: $contributor.text$</p>
$endif$
$if(contributor.role)==pfr$
<p>Proofreader: $contributor.text$</p>
$endif$
$if(contributor.role)==pht$
<p>Photographer: $contributor.text$</p>
$endif$
$endfor$
(Which can't work because it seems this syntax is not implemented.)

How can that be done as long as I use standard conform yaml metadata? I use
latest pandoc 1.13.2.

[John MacFarlane]

Post by Jan Kröger
Hi,
as long as I understood, it is possible to set a pandoc template condition
which asks if a variable's value is not zero.
But want I need is to create a condition which asks for a variable with a
certain value.
Is that possible?

No.

Post by Jan Kröger
An example: I want pandoc to write some yaml metadata (contributors names)
to the epub's titlepage to give the different contributors their
credentials (put a label in front of the name).
- role: edt
text: Person1
- role: pfr
text: Person2
- role: pht
text: Person3
- role: trl
What works is a simple list of different contributors, set in my custom
$for(contributor)$
$contributor.text$$sep$,
$endfor$
pandoc metadata.yaml book-content.md -t epub3 -o book.epub
Person1, Person2, Person3
Editor: Person1
Proofreader: Person2
Photographer: Person3
$for(contributor)$
$if(contributor.role)==edt$
<p>Editor: $contributor.text$</p>
$endif$
$if(contributor.role)==pfr$
<p>Proofreader: $contributor.text$</p>
$endif$
$if(contributor.role)==pht$
<p>Photographer: $contributor.text$</p>
$endif$
$endfor$
(Which can't work because it seems this syntax is not implemented.)
How can that be done as long as I use standard conform yaml metadata? I use
latest pandoc 1.13.2.

Two possibilities. 1) Just use the word "Editor" instead of "edt" in
your metadata. 2) Create a filter that modifies these metadata fields,
changing "edt" to "Editor" etc.

[Jan Kröger]

Will try. Thnx, John!