A utility that parses scripts and pretty prints the functions it finds. Use it to create a friendly interface to your scripts. Similar to run_lib but rustier.
cargo install runsh
Add the following to the end of your script:
runsh $(basename "$0") "$@" || "$@"
Executing a bash function from rust:
1. Command executes the program directly and does not create a shell, so you can't source a script and then invoke it.
2. We could use shellfn to source and execute but you lose the ability to see what the script is doing as it runs. This has to support long-running scripts, so that isn't any good.
It's easier to have the script invoke itself, and that's what the last line does. This means runsh doesn't actually run anything, it's just a pretty-printer for bash scripts. I'd rather have it run the functions becuase I want to keep the bash simple, so if anyone reading this has any better ideas please do get in touch.
I already wrote this in bash and called it run_lib. There are a few reasons why this is better. Here are some considerations:
1. A Rust executable is easier to distribute via cargo. It's easier for people to update.
2. Integration with a script is more or less the same.
3. The processing is much easier in Rust than it is in bash, i.e. finding and displaying multi-line comments.
4. Rust so hot right now.
Integration looks like this:
runsh $(basename "$0") "$@" || "$@"
There are two parts to this:
1. runsh $(basename "$0") "$0": this executes runsh, passing two parameters:
1. The name of the script being run ($(basename "$0")). E.g. in ./script som_function it will be script.
2. The parameters to the shell command as issued by the user ("$@"). This will be the function name and args, e.g. in ./script.sh some_function some_args it will be some_function some_args.
2. || "$@" is the fall back for when runsh returns a non-zero exit code. This is suppsoed to happen and how the function ends up getting run. runsh will validate the function name and return a non-zero exit code if it exists. When this happens "$@" will execute, which is a quick bash way to run the actual function.