How to set a variable’s default value in a config file but let it be overridden by the document's YAML metadata block?

[agreselin]

For instance, I want to set toc-title to default to "Contents". I can do it in a few ways: using --metadata toc-title='Contents' or --variable=toc-title='Contents' in a wrapper script, or with a defaults file, but none of the methods I tried can be overridden by the toc-title setting in the document's YAML metadata block. Am I missing something or should I file a feature request?

[jgm]

Yes, the command-line arguments will override settings from the metadata.

[agreselin]

Hi John! You describe the behaviour that I've seen and which is the opposite of what I'm looking for: I'd like something that can be overridden by settings from the metadata.

Thanks for this amazing piece of software :-)

[jgm]

Well, there is a way to do this. Put the things you want as overridable defaults in a separate file with just YAML metadata, and include it first on the command line, before your main file.

The values in your main file will then override the others.

[agreselin]

Thanks, and sorry for the late reply. I use it like this now

metadata=$(cat << 'EOF'
metadata:
toc-title: Contents
EOF
)

pandoc ⟨other options⟩
       --metadata-file=<(cat <<< "$metadata") \
       "$@" \
       -o "${!#%.*}".html

It's not pretty but there's worse.