Replace invalid values with default about serde-yaml HOT 2 CLOSED

#[macro_use]
extern crate serde_derive;

extern crate serde;
extern crate serde_yaml;

use serde::de::{Deserialize, Deserializer};
use serde_yaml::Value;

#[derive(Debug, PartialEq, Serialize, Deserialize, Default)]
struct Point {
    #[serde(deserialize_with = "invalid_means_default")]
    x: f64,
    y: f64,
}

fn invalid_means_default<T, D>(deserializer: D) -> Result<T, D::Error>
    where T: Default + Deserialize,
          D: Deserializer
{
    // Require the input to be valid YAML. Syntactically invalid YAML like a
    // string without a closing quote should not be set to default.
    let v: Value = Deserialize::deserialize(deserializer)?;

    // Try to deserialize T and use the default value if there is a type error.
    Ok(T::deserialize(v).unwrap_or_default())
}

fn main() {
    let point = Point::default();

    let s = serde_yaml::to_string(&point).unwrap();
    assert_eq!(s, "---\nx: 0\ny: 0");

    // How can I replace the a with a default value for x while preserving all other correct values?
    let string = "---\nx: a\ny: 0";
    let deserialized_point: Point = serde_yaml::from_str(&string).unwrap();
    assert_eq!(point, deserialized_point);
}