Function parse_args

src/argparse.rs:53–127

Parse argument list fname: Name of the current function params: Declared parameters of the function args: Positional arguments kwargs: Keyword arguments output: Output array that receives the arguments. Must have same length as `params` and must be initialized to `None`.

(
    py: Python,
    fname: Option<&str>,
    params: &[ParamDescription],
    args: &PyTuple,
    kwargs: Option<&PyDict>,
    output: &mut [Option<PyObject>],
)

///  * output: Output array that receives the arguments.
///           Must have same length as `params` and must be initialized to `None`.
pub fn parse_args(
    py: Python,
    fname: Option<&str>,
    params: &[ParamDescription],
    args: &PyTuple,
    kwargs: Option<&PyDict>,
    output: &mut [Option<PyObject>],
) -> PyResult<()> {
    assert!(params.len() == output.len());
    let nargs = args.len(py);
    let nkeywords = kwargs.map_or(0, |d| d.len(py));
    if nargs + nkeywords > params.len() {
        return Err(err::PyErr::new::<exc::TypeError, _>(
            py,
            format!(
                "{}{} takes at most {} argument{} ({} given)",
                fname.unwrap_or("function"),
                if fname.is_some() { "()" } else { "" },
                params.len(),
                if params.len() != 1 { "s" } else { "" },
                nargs + nkeywords
            ),
        ));
    }
    let mut used_keywords = 0;
    // Iterate through the parameters and assign values to output:
    for (i, (p, out)) in params.iter().zip(output).enumerate() {
        match kwargs.and_then(|d| d.get_item(py, p.name())) {
            Some(kwarg) => {
                *out = Some(kwarg);
                used_keywords += 1;
                if i < nargs {
                    return Err(err::PyErr::new::<exc::TypeError, _>(
                        py,
                        format!(
                            "Argument given by name ('{}') and position ({})",
                            p.name(),
                            i + 1
                        ),
                    ));
                }
            }
            None => {
                if i < nargs {
                    *out = Some(args.get_item(py, i));
                } else {
                    *out = None;
                    if !p.is_optional {
                        return Err(err::PyErr::new::<exc::TypeError, _>(
                            py,
                            format!(
                                "Required argument ('{}') (pos {}) not found",
                                p.name(),
                                i + 1
                            ),
                        ));
                    }
                }