Plugins vs customization of syntax/parser - questions

Questions: Will it be / Is it possible for plugins to:

  • tell Obsidian which filename extensions are to be treated as notes?
  • recognize custom syntax in editor mode?
  • preprocess custom syntax before parsing from markdown to html for preview?
  • or modify or substitute current parser by custom one to allow parsing any syntax (Roam, GFM, MultiMarkdown, Markua, …)?