Apex Title Filter

Ruby JSON filter for the Apex Markdown processor, compatible with Pandoc-style filters (docs).

This filter:

• Looks for a document title in Pandoc JSON metadata (meta.title).
• If the first block is not already a level‑1 header (Header 1), prepends an H1 using that title.

The transformation is:

• Input: Pandoc JSON document (Pandoc object) on stdin.
• Output: Modified Pandoc JSON document on stdout.

Script

The main filter implementation lives in title.rb:

./title.rb < in.json > out.json

It expects a full Pandoc‑style JSON document as produced by:

pandoc -t json input.md | ./title.rb | pandoc -f json -t html

or, when used via Apex:

apex --filter title input.md > output.html

Installation for Apex

1. Ensure the script is executable:

   chmod +x title.rb

2. Install it into your Apex filters directory:

   mkdir -p ~/.config/apex/filters
   cp title.rb ~/.config/apex/filters/title

3. Run Apex with the filter enabled:

   apex --filter title input.md > output.html

To run all installed filters in the directory:

apex --filters input.md > output.html

You can also combine this with other filters (e.g., delink) simply by having multiple executables in ~/.config/apex/filters and/or using multiple --filter NAME arguments.