Adding a banner / warning in the generated files (like .md, .html, ...)

[cavo789]

Description

Hi all

Did you know if it's possible to inject a warning at the top of the generated file like // Please don't update this file because it's a generated one. Please update the .qmd file then render it again as .md?

The idea is thus to notify the user to not make changes in a file generated by Quarto but to inform him that he need update the source file and render it again.

Thanks !

[mcanouil]

You can use a Lua filter:

---
title: "Quarto Playground"
format: gfm
filters:
  - add_comment.lua
---

This is a playground for Quarto.

-- file: add_comment.lua
function Pandoc(doc)
  local comment = pandoc.RawBlock('html', '<!--- Generated file. Do not edit directly. --->')
  table.insert(doc.blocks, 1, comment)
  return doc
end

Note that a comment in Quarto/Pandoc is tricky, depending on what it is for exactly, see:

• How to comment out some contents in .qmd files? #3330

[cavo789]

Merci Michaël ! J'apprécie fortement !

Thanks Michaël, I really appreciate. I'll try this next week (first learn what is a filter and how implement it).

[cavo789]

Once again, thank you @mcanouil !

I'm not sure I'm doing it right.

I've followed the Quick Start documentation for creating a new filter and got this structure:

❯ tree
.
├── add_banner
│   ├── README.md
│   ├── _extensions
│   │   └── add_banner
│   │       ├── _extension.yml
│   │       └── add_banner.lua
│   └── example.qmd
└── index.qmd

I've copied your LUA code in file add_banner/_extensions/add_banner/add_banner.lua and your markdown example in index.qmd.

Running quarto render index.qmd fails with this error: ERROR (/opt/quarto/share/filters/main.lua:3440) cannot open add_banner.lua: No such file or directory.

I understand from the official doc I need to have a folder _extensions (and not add_banner/_extensions) so I move folder add_banner/_extensions one level up (and remove the add_banner folder):

❯ tree
.
├── _extensions
│   └── add_banner
│       ├── _extension.yml
│       └── add_banner.lua
├── index.md
└── index.qmd

The last thing I need to do to make it working is to replace in my index.qmd file the line - add_comment.lua and remove the extension so replace with - add_comment.

And now, it works as expected.

Once again, many thanks for the great support.