process

Import with:

import process

The process module exposes command-line arguments, environment variables, the current working directory, and child-process execution.

process.args()

Returns a List[Str] containing the command-line arguments passed to the Novum program excluding the executable name.

for arg in process.args() {
    print(arg)
}

process.env(name)

Reads an environment variable.

let home = process.env("HOME")

The result is an Option: Option.Some(Str) when the variable exists and Option.None when it does not.

process.set_env(name, value)

Sets an environment variable for the current process and returns Result.Ok(Unit) on success.

process.set_env("NOVUM_MODE", "debug")

process.cwd()

Returns the current working directory as a Path, wrapped in Result:

let cwd = process.cwd()

The successful result is Result.Ok(Path).

process.run(command, arguments)

Runs an external command and captures its output.

let result =
    process.run(
        "python",
        ["--version"]
    )

The second argument must be a List[Str].

On success, the returned value is Result.Ok(Dict) with these properties:

Property	Type	Meaning
status	Int	Process exit code, or -1 when no ordinary code is available
stdout	Str	Captured standard output
stderr	Str	Captured standard error

Example:

let result = process.run("echo", ["hello"])

match result {
    Result.Ok(output) => {
        print(output["status"])
        print(output["stdout"])
    }
    Result.Err(message) => print(message)
}

Warning

process.run() executes a real external process. Never pass untrusted command names or arguments to it without validating them first.