Maybe building another programming language can be accelerated by deriving its M libraries from another, using some kind of abstract libraries or translation methods, through a service similar to LSP.
He's saying about actual working code, something akin to universal libraries you could use from any language. Or maybe some auto-translation/hooking up of libraries from another language, through some sort of "library protocol".
On another note: huge thanks for rust-analyzer, not only is it my main daily driver, but we also used it as a reference for implementation of "deno lsp" - the language server that ships with Deno.
I can't say I am a user of deno today, but my feelings about deno remind me my feelings about Rust circa 2015: it's not clear if the thing succeeds, but, if it does, that would be a huge boon for the whole industry, as finally "better is better" would take over "worse is better". Deno has all the potential to become the first really dependable scripting environment!
So, I wish you luck and hope one day I'll migrate my jekyll+asciidoctor blog to deno :-)