meta.sh | A tiny shell written in C | Command Line Interface library

There's jl-parse-file in the FemtoLisp implementation of the Julia parser. You can call it from the Lisp REPL (julia --lisp), and it returns an S-expression for the whole file. Since Julia's Expr is not much different from Lisp S-expressions, that might be enough for you purposes.

I still wonder how one would access the result of this from within Julia. If I understand correctly, the Lisp functions are not exported from libjulia, so there's no direct way to just use a ccall. But maybe a variant of jl_parse_eval_all can be implemented.

You are not joining the tables properly :

You need to explicitly cast descr to K.char type:

Here's an example of a function that takes an "s_expression" in tuple form, and generates the corresponding Expr object:

chepner's comment is right about the immediate problem: you're passing the script names to bash wrong. After the -c option, bash expects a single argument containing the command to execute (optionally followed by arguments to pass to it, starting with $0). If you want to execute multiple commands, you need to combine them into a single compound command, like /Users/qwe/Music/meta.sh & /Users/qwe/Music/seta.sh.

But I think you're also using launchd wrong. Launchd is really intended to launch processes, and then monitor them; this requires that they stay in the foreground. Things that background themselves out from under launchd tend to confuse it, leading to weird problems. For example, consider the command string I gave above. It runs meta.sh in the background, and seta.sh in the foreground. You said that meta.sh is a long-running process, but I assume seta.sh just does its job and exits? If so, launchd will see that seta.sh (the foreground process) has exited, figure that any subprocesses (meta.sh) are leftover orphans and it should "clean them up", i.e. kill them. Oops, meta.sh is no longer long-running.

If you really just want both meta.sh and seta.sh to be launched, it'd be better to create two separate launchd items (i.e. two .plist files) for them.

If you need to run them together for some reason, probably the best way is to essentially create a small script that runs both of them and then waits for both to exit, and pass that "script" to bash as the parameter to the -c option. Note that this means the entire "script" has to be in a single string in the ProgramArguments array: