i already use prompt_toolkit on droid as it uses concurrent futures for completion and threads are allowed on that platform, and yeah it is quite good.

but no way to use it on emscripten where cpython is 100% async ( it uses dummy_threading to load asyncio ). best you can do is fill an history buffer with the indented input, eval the whole thing when it's done with PyRun_SimpleString. 

having cpython storing code until sync/async path can  be choosen could save a lot of external hacks with minimal impact on original repl loop, unless somebody is willing to make it *fully* async ( i know i can't ). 

The original repl input loop is really not made for async and i don't know if Sylvain Beuclair's work on "emterpreted" cpython covers also python3.

thx for the pointers anyway and your article on async and ast was inspiration.