for funto learn Rusthave a shell that I can customize a bit for my own needs
Because we can. ☺
Bash is where most people come from and what they are familiar with. Cicada is trying to support most common cases that Bash supports, except the Bash scripting language.
In following aspects, cicada wants to do a better (sanity) job:
Compare to shells like zsh/fish, cicada tends to be a simpler shell. Audience of cicada shell should be people that are seeking simplicity and speed, while not full-feature.
As the above answers hints, while cicada is trying to be POSIX, it will not be a fully POSIX shell. However, if any command pattern is common and cicada is missing support, we could add it.
You can invoke scripts with $ ./my-script.sh as long as they have a shebang
(#!/bin/bash) at the top. Or you can always run them as:
$ bash my-script.sh.
Cicada does not recognize these scripts itself. You cannot integrate these shell scripts/functions in RC files to initiate cicada shell. But you could use the scripting ability of cicada.
Cicada is a Unix shell, sorry. There are a lot of alternative cool shells for Windows, for example xonsh.