Looks like the goal of this project is to be a replacement for bash with improved interactivity. That seems reasonable, compared to what you can do with zsh or fish bash is far behind concerning interactivity.
While I personally think shells that abandon POSIX/bash compliance are much more interesting as those can implement a sane scripting language, sticking with bash but improving interactivity is probably going to make more users happy as bash is so ubiquitous.
Is it really? Projects like ble.sh [1] seem to pull off advanced features like syntax highlighting and enhanced completion with pure bash without the need for reimplementing a whole shell from the ground up.
Totally agree, but having used zsh, fish and elvish as my daily driver shell (each for at least 1 month) I think that not having POSIX/bash compliance eventually becomes an annoyance.
I like zsh because it is mostly (entirely?) POSIX compliant, but adds extended features. I think that's the best approach to make it easier for people to start using your shell.
random note: back when the Go language was first released I wanted to try it out.. I started making a shell that I called GoSH. Didn't get very far, you could execute programs, change directories etc. It was fun! And taught me a lot about low level languages.
The need for complete POSIX scope has just never been an issue for me using zsh. I shebang all my scripts to bash (or even plain old sh if its for some stripped down container). I guess if I wanted a lot of functions to run tasks natively it would, but never had that need (but aware some might).
While I personally think shells that abandon POSIX/bash compliance are much more interesting as those can implement a sane scripting language, sticking with bash but improving interactivity is probably going to make more users happy as bash is so ubiquitous.