impl FromStr for IntegerOrFloat

src/from_str.rs

@@ -0,0 +1,16 @@
+use core::num::ParseFloatError;
+use core::str::FromStr;
+
+use super::IntegerOrFloat::{self, *};
+
+impl FromStr for IntegerOrFloat {
+    type Err = ParseFloatError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(
+            match s.parse::<i32>() {
+                Ok(i) => Integer(i),
+                Err(_) => Float(s.parse::<f32>()?),
+            }
+        )
+    }
+}

src/lib.rs

@@ -6,6 +6,7 @@ use serde::{Serialize, Deserialize};
 mod hash;
 
 pub mod encode;
+mod from_str;
 
 /// The UFO data type "integer or float".
 #[cfg_attr(feature = "default", derive(Serialize, Deserialize))]

tests/from_str.rs

@@ -0,0 +1,21 @@
+use integer_or_float::IntegerOrFloat::{self, *};
+
+#[test]
+fn test_from_str() {
+    assert_eq!("12".parse::<IntegerOrFloat>().unwrap(), Integer(12));
+    assert_eq!("12.0".parse::<IntegerOrFloat>().unwrap(), Float(12.0));
+}
+
+#[test]
+fn test_from_str_subnormal_nan() {
+    assert!(f32::from("NaN".parse::<IntegerOrFloat>().unwrap()).is_nan());
+    assert!(f32::from("INF".parse::<IntegerOrFloat>().unwrap()).is_infinite());
+    assert!(f64::from("NaN".parse::<IntegerOrFloat>().unwrap()).is_nan());
+    assert!(f64::from("INF".parse::<IntegerOrFloat>().unwrap()).is_infinite());
+}
+
+#[test]
+fn test_from_str_fail() {
+    assert!("12.v0".parse::<IntegerOrFloat>().is_err());
+    assert!("nanners".parse::<IntegerOrFloat>().is_err());
+}