[andsoitis]

I have not seen Squeak (or other Smalltalk environments, e.g. Pharo) being used like and IDE, which is what I infer you mean by "developer... emacs replacement".

It certainly seems possible and could potentially make for a great IDE foundation, I just haven't seen it done, other than the Glamorous Toolkit - https://gtoolkit.com

[pjmlp]

Interesting statement, given that modern IDEs trace back to Lisp and Smalltalk graphical workstations.

[andsoitis]

Clarification: I meant using those environments for other languages, like people do with emacs, which is what I inferred the person I responded to was asking.