I'm going to use the "[Idea Bin]" flag to indicate ideas or projects that I would love to develop if I had more time, but realistically admit that I'll never finish. If you choose to use one of these ideas, you have my permission and best wishes.
An implementation of bash on Parrot would be a great test of Parrot's I/O capabilities. The source code for bash is fairly readable considering how arcane are some of its supported operations. Bash has a rather healthy test suite that could be reused during development.
I spent many commutes pondering possible names for such a port, but never came up with a great one. I wanted "posh" to work, but never came up with the right words for the acronym. "bashup" = bash-under-parrot felt too forced.
If such a parrot implementation would enable you to call out to other languages via namespace prefixes on functions, this could let shell be a better glue language than ever. You could incrementally port hairy shell scripts to more expressive programming languages.
Then you could switch all of your
Furthermore, I've been a csh/tcsh user for 15 years and have always envied the power of bash, but never bothered learning more than the rudiments. This would be an excuse to learn it deeply.