async-graphql/src/scalars/floats.rs

use crate::{InputValueError, InputValueResult, ScalarType, Value};
use async_graphql_derive::Scalar;

macro_rules! float_scalar {
    ($($ty:ty),*) => {
        $(
        /// The `Float` scalar type represents signed double-precision fractional values as specified by [IEEE 754](https://en.wikipedia.org/wiki/IEEE_floating_point).
        #[Scalar(internal, name = "Float")]
        impl ScalarType for $ty {
            fn parse(value: Value) -> InputValueResult<Self> {
                match value {
                    Value::Number(n) => Ok(n
                        .as_f64()
                        .ok_or_else(|| InputValueError::from("Invalid number"))?
                        as Self),
                    _ => Err(InputValueError::ExpectedType(value)),
                }
            }

            fn is_valid(value: &Value) -> bool {
                match value {
                    Value::Number(_) => true,
                    _ => false,
                }
            }

            fn to_value(&self) -> Value {
                Value::Number(serde_json::Number::from_f64(*self as f64).unwrap())
            }
        }
        )*
    }
}

float_scalar!(f32, f64);