You'll need to declare a vec of (input_type, output_type) pairs here -- lots of examples in the other command files. You'll see the test fail for your example until you declare these:

thread 'network::url::parse::test::test_examples' panicked at 'The example `echo 'http://www.example.com/foo/bar?p=section&s=&f[name]=vldc' | url parse` demonstrates a transformation of type String -> Record([("scheme", String), ("host", String), ("path", String), ("query", String), ("params", Record([("p", String), ("s", String), ("f[name]", String)]))]). However, this does not match the declared signature: []. (Did you forget to declare the input and output types for the command?) For this command, `vectorizes_over_list` is false and `operates_on_cell_paths()` is true.', crates/nu-command/src/example_test.rs:178:21

I believe that we don't add any words from the command name itself to the search terms: just any related terms that you believe users might enter when looking for this.

hmm thanks for the explanation, so maybe "scheme", "hostname", "port", "path", and "parameters" ? That it's what the command returns

Although several commands still do it in their examples, echo isn't necessary any longer and for cases like this IMO we should omit the echo: a data structure can just be supplied as input to a pipeline.

What do you think about writing this something like the following?

vals.push(Value::String {
    val: url.port().map(|p| p.to_string()).unwrap_or("".into()),
    span: head,
});

thanks that's much better :) I am new to Rust, I still don't know the best way to handle some things.
I'll change to your code in next commit.

What do you think about writing this something like this?

let (param_cols, param_vals) = result
    .into_iter()
    .map(|(k, v)| (k, Value::String { val: v, span: head }))
    .unzip();

Inconsistent capitalization in error message. (It's nice to have our error messages perfect!)

Do you think we should keep url path and url query and url scheme? My immediate reaction is that they should not exist if we have url parse since one should just do e.g. ($url | url parse).path.

Any interest in adding the other parsed components while you're at it? I think username and password are pretty useful for people working with ssh, and fragment is common... may as well take them all?

I believe we should leave this as an integer seeing as Rust is providing it as an int.

in that case, what should be the output when there's no port on url ? An empty string? I could do something like this for port value:

match url.port() {
    Some(p) => Value::Int {
        val: p as i64,
        span: head,
    },
    None => Value::String {
        val: "".into(),
        span: head,
    }
},

But this way, the url parse output type for port will be string or int depending on input.

Oh you're right, sorry, I think what I said doesn't make sense until/unless Nushell gains an Option type in the future. As you have it is the way for now.

I think that we generally want to avoid testing the formatted output from table like this. Tests like this are fragile and will break whenever we tweak Nu's display logic.

Alternative approaches:

1. Figure out a way to test equality against a Value::Record (instead of text output) in Rust
2. Do the equality check against a Nu record in Nu code. Something like:

let actual = nu!(
    cwd: ".", pipeline(
        r#"
            ("https://www.abc.com" | url parse) == {scheme: 'https', username: '', ...}
        "#
));
assert_eq!(actual.out, "true");

(there's probably a better way than that, it's just the first thing that came to mind)

that makes sense, I just copied how some other tests were done. I can change the tests, just waiting for confirmation

tests updated