Whipping up a new Shell – Lash#Cat9

Arcan, the unique development framework for user interfaces that’s exploring a ton of new and different ideas, has released a new project – Lash#Cat9, a new command line shell.

A guiding principle is the role of the textual shell as a frontend instead of a clunky programming environment. The shell presents a user-facing, interactive interface to make other complex tools more approachable or to glue them together into a more advanced weapon. Cat9 is entirely written in Lua, so scripting in it is a given, but also relatively uninteresting as a feature — there are better languages around for systems programming, and better UI paradigms for automating work flows.

Another is that of delegation – textual shells naturally evolved without assuming a graphical one being present. That is rarely the case today, yet the language for sharing between the two is unrefined, crude and fragile. The graphical shell is infinitely more capable of decorating and managing windows, animating transitions, routing inputs and tuning pixels for specific displays. It should naturally be in charge of such actions.

Another is to make experience self documenting – that the emergent patterns on how your use of command line processing gets extracted and remembered in a form where re-use becomes natural. Primitive forms of this are completions from command history and aliases, but there is much more to be done here.

I’m not a heavy shell user, so I’m not going to make any subjective statements here. It at least seems remarkably interesting, and I’m sure there’s quite a few among us who would love to play with this.


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