Devyn Cairns efe25e3f58
Better generic errors for plugins (and perhaps scripts) (#12236)
# Description
This makes `LabeledError` much more capable of representing close to
everything a `miette::Diagnostic` can, including `ShellError`, and
allows plugins to generate multiple error spans, codes, help, etc.

`LabeledError` is now embeddable within `ShellError` as a transparent
variant.

This could also be used to improve `error make` and `try/catch` to
reflect `LabeledError` exactly in the future.

Also cleaned up some errors in existing plugins.

# User-Facing Changes
Breaking change for plugins. Nicer errors for users.
2024-03-21 12:27:21 +01:00

54 lines
1.8 KiB
Rust

use nu_plugin::EvaluatedCall;
use nu_protocol::{LabeledError, Value};
pub struct Example;
impl Example {
pub fn print_values(
&self,
index: u32,
call: &EvaluatedCall,
input: &Value,
) -> Result<(), LabeledError> {
// Note. When debugging your plugin, you may want to print something to the console
// Use the eprintln macro to print your messages. Trying to print to stdout will
// cause a decoding error for your message
eprintln!("Calling test {index} signature");
eprintln!("value received {input:?}");
// To extract the arguments from the Call object you can use the functions req, has_flag,
// opt, rest, and get_flag
//
// Note that plugin calls only accept simple arguments, this means that you can
// pass to the plug in Int and String. This should be improved when the plugin has
// the ability to call back to NuShell to extract more information
// Keep this in mind when designing your plugin signatures
let a: i64 = call.req(0)?;
let b: String = call.req(1)?;
let flag = call.has_flag("flag")?;
let opt: Option<i64> = call.opt(2)?;
let named: Option<String> = call.get_flag("named")?;
let rest: Vec<String> = call.rest(3)?;
eprintln!("Required values");
eprintln!("a: {a:}");
eprintln!("b: {b:}");
eprintln!("flag: {flag:}");
eprintln!("rest: {rest:?}");
if let Some(v) = opt {
eprintln!("Found optional value opt: {v:}")
} else {
eprintln!("No optional value found")
}
if let Some(v) = named {
eprintln!("Named value: {v:?}")
} else {
eprintln!("No named value found")
}
Ok(())
}
}