#![allow(clippy::trait_duplication_in_bounds)] // https://github.com/rust-lang/rust-clippy/issues/8757 use serde::{Deserialize, Deserializer}; use std::fmt::{self, Display}; use std::marker::PhantomData; use std::str::FromStr; pub struct NumberVisitor { marker: PhantomData, } impl<'de, T> serde::de::Visitor<'de> for NumberVisitor where T: TryFrom + TryFrom + FromStr, >::Error: Display, >::Error: Display, ::Err: Display, { type Value = T; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { formatter.write_str("an integer or string") } fn visit_u64(self, v: u64) -> Result where E: serde::de::Error, { T::try_from(v).map_err(serde::de::Error::custom) } fn visit_i64(self, v: i64) -> Result where E: serde::de::Error, { T::try_from(v).map_err(serde::de::Error::custom) } fn visit_str(self, v: &str) -> Result where E: serde::de::Error, { v.parse().map_err(serde::de::Error::custom) } } fn deserialize_integer_or_string<'de, D, T>(deserializer: D) -> Result where D: Deserializer<'de>, T: TryFrom + TryFrom + FromStr, >::Error: Display, >::Error: Display, ::Err: Display, { deserializer.deserialize_any(NumberVisitor { marker: PhantomData, }) } #[derive(Deserialize, Debug)] pub struct Struct { #[serde(deserialize_with = "deserialize_integer_or_string")] pub i: i64, } #[test] fn test() { let j = r#" {"i":100} "#; println!("{:?}", serde_jsonc::from_str::(j).unwrap()); let j = r#" {"i":"100"} "#; println!("{:?}", serde_jsonc::from_str::(j).unwrap()); }