Method format

crates/vm/src/vm/vm_ops.rs:551–576

PyObject_Format

(&self, obj: &PyObject, format_spec: PyStrRef)

    // PyObject_Format
    pub fn format(&self, obj: &PyObject, format_spec: PyStrRef) -> PyResult<PyStrRef> {
        if format_spec.is_empty() {
            let obj = match obj.to_owned().downcast_exact::<PyStr>(self) {
                Ok(s) => return Ok(s.into_pyref()),
                Err(obj) => obj,
            };
            if obj.class().is(self.ctx.types.int_type) {
                return obj.str(self);
            }
        }
        let bound_format = self
            .get_special_method(obj, identifier!(self, __format__))?
            .ok_or_else(|| {
                self.new_type_error(format!(
                    "Type {} doesn't define __format__",
                    obj.class().name()
                ))
            })?;
        let formatted = bound_format.invoke((format_spec,), self)?;
        formatted.downcast().map_err(|result| {
            self.new_type_error(format!(
                "__format__ must return a str, not {}",
                &result.class().name()
            ))
        })
    }
    pub fn format_utf8(&self, obj: &PyObject, format_spec: PyStrRef) -> PyResult<PyRef<PyUtf8Str>> {
        self.format(obj, format_spec)?.try_into_utf8(self)
    }