plan9 rc in rust

• Goal: Implement plan9 rc in Rust.
• Plan: Stay true to 9front implementation.
• License: GPL-3.0-or-later
• Disclaimer: This is just a hobby project.

ChangeLog

0.0.1-alpha.3

• milestone: lexer can successfully tokenize all rc scripts under plan9front.git.
• handle reading rc script from standard input.
• numerious fixes to the tokenizer.
• fix word characters and handle quotes and semicolon in tokenizer.
• handle EOF and ^C.

0.0.1-alpha.2

• teach tokenizer to skip # comments.
• teach tokenizer I/O redirection and FD redirection.
• teach tokenizer variable assignment, e.g. a=1.
• teach tokenizer command `{cmd}, and `split {cmd}.
• teach tokenizer command redirection, aka <{cmd} and >{cmd}.
• teach tokenizer $argument(subscript), $"argument, and $#argument

0.0.1-alpha.1

• add initial repl using rustyline.
• implement initial lexer/tokenizer using nom.