Expose argv[0]

[p00f]

Related problem

I would like argv[0] ie the name the script was invoked with, exposed in scripts

Describe the solution you'd like

argv[0] is available as the path argument here:

nushell/crates/nu-cli/src/eval_file.rs

Line 19 in 77a1c3c

path: String,

The information is lost here:

nushell/crates/nu-cli/src/eval_file.rs

Lines 34 to 44 in 77a1c3c

	let file_path = canonicalize_with(&path, cwd).unwrap_or_else(|e| {
	let working_set = StateWorkingSet::new(engine_state);
	report_error(
	&working_set,
	&ShellError::FileNotFoundCustom(
	format!("Could not access file '{}': {:?}", path, e.to_string()),
	Span::unknown(),
	),
	);
	std::process::exit(1);
	});

nushell/crates/nu-cli/src/eval_file.rs

Lines 97 to 100 in 77a1c3c

	stack.add_env_var(
	"CURRENT_FILE".to_string(),
	Value::string(file_path.to_string_lossy(), Span::unknown()),
	);

Describe alternatives you've considered

$"./($env.CURRENT_FILE | path relative-to (pwd))", but this is not necessarily the same thing as argv[0] (an obvious exception is windows)

Additional context and details

No response

[p00f]

This should also be used when reporting usage errors:

> ./tools/build.nu
Error: nu::parser::missing_positional

  × Missing required positional argument.
   ╭─[<commandline>:1:1]
 1 │ main
   ·     ▲
   ·     ╰── missing src
   ╰────
  help: Usage: main <src> <dest> . Use `--help` for more information.

In the last line, ./tools/build.nu should be used instead of main