I am using clap for a custom cli that I am making , in which I use Vec<(char,Number)> , as HashMap<char,Number> gave a list of more errors. So my code compiles , but at runtime it gives me
Finished dev [unoptimized + debuginfo] target(s) in 1.13s
Running `C:\Users\Aarav Aditya Shah\Documents\GitHub\project-codebases\rust\arkley\target\debug\arkley_cli.exe evaluate -e "2x +5t" -v x=4`
thread 'main' panicked at 'Mismatch between definition and access of `value`. Could not downcast to alloc::vec::Vec<(char, Number)>, need to downcast to (char, num_notation::number::Number)
', arkley_cli\src\parser.rs:51:17
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: process didn't exit successfully: `C:\Users\Aarav Aditya Shah\Documents\GitHub\project-codebases\rust\arkley\target\debug\arkley_cli.exe evaluate -e "2x +5t" -v x=4` (exit code: 101)
Note : (char,Number) is replacable with (char,f64) and error still happens.
Here is the code that i use
#[derive(Subcommand)]
pub(super) enum Arguments {
#[clap(about = "Evaluate a mathematical expression")]
Evaluate {
#[arg(
short = 'e',
long = "expression",
required = true,
)]
expression_or_equation : String,
#[arg(
short,
long,
value_parser = parse_key_val,
)]
value : Vec<(char,f64)> // Number replaced to f64
}
}
// [Copyed from here](https://github.com/clap-rs/clap/blob/master/examples/typed-derive.rs#L46) with custom changes
fn parse_key_val(s: &str) -> Result<(char,Number), Box<dyn Error + Send + Sync + 'static>> {
let pos = s
.trim() // Added trim here
.find('=')
.ok_or_else(|| format!("invalid KEY=value: no `=` found in `{s}`"))?;
Ok((s[..pos].parse()?, s[pos + 1..].try_into()?))
}
So I copyed the example given so pass key=value input with clap , but this gives me an error.
I thought to use this answer. Given below
use clap::Parser; // 4.2.7
#[derive(Parser, Debug)]
#[clap(author, version, about, long_about = None)]
pub struct Cli {
#[clap(short, long, value_delimiter = ' ', num_args = 1..)]
pub list: Option<Vec<i32>>,
}
fn main() {
let cli = Cli::parse();
print
But that leads to ...
error[E0599]: the method `value_parser` exists for reference `&&&&&&_AutoValueParser<Vec<(char, Number)>>`, but its trait bounds were not satisfied
--> arkley_cli\src\parser.rs:46:9
|
46 | #[clap(short, long, value_delimiter = ' ', num_args = 1..)]
| ^ method cannot be called on `&&&&&&_AutoValueParser<Vec<(char, Number)>>` due to unsatisfied trait bounds
|
::: C:\Users\Aarav Aditya Shah\.cargo\registry\src\index.crates.io-6f17d22bba15001f\clap_builder-4.4.7\src\builder\value_parser.rs:2462:1
|
2462 | pub struct _AutoValueParser<T>(std::marker::PhantomData<T>);
| ------------------------------ doesn't satisfy `_: _ValueParserViaParse`
|
::: C:\Users\Aarav Aditya Shah\.rustup\toolchains\stable-x86_64-pc-windows-msvc\lib/rustlib/src/rust\library\alloc\src\vec\mod.rs:396:1
|
396 | pub struct Vec<T, #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global> {
| ------------------------------------------------------------------------------------------------
| |
| doesn't satisfy `Vec<(char, arkley_algebra::Number)>: From<&'s str>`
| doesn't satisfy `Vec<(char, arkley_algebra::Number)>: FromStr`
| doesn't satisfy `Vec<(char, arkley_algebra::Number)>: ValueEnum`
| doesn't satisfy `_: From<&OsStr>`
| doesn't satisfy `_: From<OsString>`
| doesn't satisfy `_: From<String>`
| doesn't satisfy `_: ValueParserFactory`
|
= note: the following trait bounds were not satisfied:
`Vec<(char, arkley_algebra::Number)>: ValueEnum`
which is required by `&&&&&_AutoValueParser<Vec<(char, arkley_algebra::Number)>>: clap::builder::via_prelude::_ValueParserViaValueEnum`
`Vec<(char, arkley_algebra::Number)>: ValueParserFactory`
which is required by `&&&&&&_AutoValueParser<Vec<(char, arkley_algebra::Number)>>: clap::builder::via_prelude::_ValueParserViaFactory`
`Vec<(char, arkley_algebra::Number)>: From<OsString>`
which is required by `&&&&_AutoValueParser<Vec<(char, arkley_algebra::Number)>>: clap::builder::via_prelude::_ValueParserViaFromOsString`
`Vec<(char, arkley_algebra::Number)>: From<&'s std::ffi::OsStr>`
which is required by `&&&_AutoValueParser<Vec<(char, arkley_algebra::Number)>>: clap::builder::via_prelude::_ValueParserViaFromOsStr`
`Vec<(char, arkley_algebra::Number)>: From<std::string::String>`
which is required by `&&_AutoValueParser<Vec<(char, arkley_algebra::Number)>>: clap::builder::via_prelude::_ValueParserViaFromString`
`Vec<(char, arkley_algebra::Number)>: From<&'s str>`
which is required by `&_AutoValueParser<Vec<(char, arkley_algebra::Number)>>: clap::builder::via_prelude::_ValueParserViaFromStr`
`Vec<(char, arkley_algebra::Number)>: FromStr`
which is required by `_AutoValueParser<Vec<(char, arkley_algebra::Number)>>: clap::builder::via_prelude::_ValueParserViaParse`
= note: this error originates in the macro `clap::value_parser` (in Nightly builds, run with -Z macro-backtrace for more info)
So I am not really sure what to do to solve this issue , so if anyone has any ideas plz do tell