expose argv[0] as $env.PROCESS_PATH

[p00f]

closes #11059

Description

I'm not sure what the consensus was after discussing this in discord, so I'm creating a PR as suggested

User-Facing Changes

$env.PROCESS_PATH can now be used in scripts to get the name the script was invoked with

#!/usr/bin/env nu

def main [] {
    printf $"I was called as ($env.PROCESS_PATH)"
}

/tmp/workspaces/0PMKZ: ./foo
I was called as ./foo
/tmp/workspaces/0PMKZ: nu foo
I was called as foo

Tests + Formatting

After Submitting

[p00f]

@fdncred @sophiajt

[p00f]

even if we don't reach a consensus on this, i'd like to at least fix this: #11059 (comment), so pointers would be appreciated

[fdncred]

ORIGINAL_CMDLINE infers the command and all the parameters, is that how it works?

[p00f]

No, it's already there (all the way back from nu's main - which uses std::env::args())

This is why ORIGINAL_CMDLINE is a bad name

@fdncred edited^^^

[fdncred]

ok, I don't really like ORIGINAL_CMDLINE so I'm throwing out some others.

• PROGRAM_NAME
• EXE_NAME
• EXECUTABLE
• PROGRAM_FILENAME
• LAUNCH_CMD
• PROCESS_PATH
• ARGV0

I'm kind of leaning towards PROCESS_PATH, any takers?

[p00f]

Same

[sholderbach]

When the name bikeshedding is done let's update the title to make the commit better discoverable.

[p00f]

@sholderbach does the pr title look good?

[sholderbach]

Thanks! 👍

[p00f]

also, when a script has a def main,

> ./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.

the error message (last line) should also use this process path instead of main.

Where is the code for this?

[fdncred]

Let's handle the "main" part in another PR. My suggestion would be to search for "main" in the code and MissingPositional to see where they're used.

Seems like this is what's being called. You may be able to track it down from here.

nushell/crates/nu-protocol/src/parse_error.rs

Lines 341 to 347 in 5d28375

	#[error("Missing required positional argument.")]
	#[diagnostic(
	code(nu::parser::missing_positional),
	help("Usage: {2}. Use `--help` for more information.")
	)]
	MissingPositional(String, #[label("missing {0}")] Span, String),

[amtoine]

@p00f
i've updated the PR description (a bit too late), can you confirm it's correct?

[p00f]

@amtoine fixed it