Pandoc in the Browser with WASM

From the pandoc release announcement: https://github.com/jgm/pandoc/releases/3.9 :

> Starting with this release, pandoc can be compiled to WASM, making it possible to use pandoc in the browser. A full-featured GUI interface is provided at https://pandoc.org/app

This is really nice to know. I remember trying to compile pandoc to Wasm after finding out that ghc had Wasm support, hitting all kinds of problems and then realising that there was no real way to post an issue to Haskell's gitlab repo without being pre-approved.

I guess now with LLMs, this makes more sense than ever, but it was a frustrating experience.

The web app can be found at https://pandoc.org/app . This has almost the full power of the command-line app, subject to the limitations imposed by the WASM sandbox. Thus:

- the app cannot fetch resources using HTTP

- JSON filters are not supported, as they involve external programs

- Lua filters are supported, but only if they don't try to do system IO operations or run external programs

- Output to PDF is supported only via Typst (using the WASM version of Typst).

> ERROR: Unknown input format pdf Pandoc can convert to PDF, but not from PDF

Darn