Improved serialization/deserialization for floating point numbers.

Cargo.toml

@@ -10,6 +10,7 @@ readme = "README.md"
 keywords = ["yaml", "serde"]
 
 [dependencies]
+dtoa = "0.4"
 linked-hash-map = "0.5"
 num-traits = "0.1.37"
 serde = "1.0"

src/de.rs

@@ -11,6 +11,7 @@
 //! This module provides YAML deserialization with the type `Deserializer`.
 
 use std::collections::BTreeMap;
+use std::f64;
 use std::fmt;
 use std::io;
 use std::str;
@@ -490,6 +491,16 @@ fn visit_untagged_str<'de, V>(visitor: V, v: &str) -> Result<V::Value>
  if let Ok(n) = v.parse() {
  return visitor.visit_i64(n);
  }
+ match v.trim_left_matches('+') {
+ ".inf" | ".Inf" | ".INF" => return visitor.visit_f64(f64::INFINITY),
+ _ => (),
+ }
+ if v == "-.inf" || v == "-.Inf" || v == "-.INF" {
+ return visitor.visit_f64(f64::NEG_INFINITY);
+ }
+ if v == ".nan" || v == ".NaN" || v == ".NAN" {
+ return visitor.visit_f64(f64::NAN);
+ }
  if let Ok(n) = v.parse() {
  return visitor.visit_f64(n);
  }

src/lib.rs

@@ -30,7 +30,7 @@
 //!
 //! // Serialize it to a YAML string.
 //! let s = serde_yaml::to_string(&map).unwrap();
-//! assert_eq!(s, "---\nx: 1\n\"y\": 2");
+//! assert_eq!(s, "---\nx: 1.0\n\"y\": 2.0");
 //!
 //! // Deserialize it back to a Rust type.
 //! let deserialized_map: BTreeMap<String, f64> = serde_yaml::from_str(&s).unwrap();
@@ -53,7 +53,7 @@
 //! let point = Point { x: 1.0, y: 2.0 };
 //!
 //! let s = serde_yaml::to_string(&point).unwrap();
-//! assert_eq!(s, "---\nx: 1\n\"y\": 2");
+//! assert_eq!(s, "---\nx: 1.0\n\"y\": 2.0");
 //!
 //! let deserialized_point: Point = serde_yaml::from_str(&s).unwrap();
 //! assert_eq!(point, deserialized_point);
@@ -78,6 +78,7 @@
  empty_enum,
 ))]
 
+extern crate dtoa;
 extern crate linked_hash_map;
 extern crate num_traits;
 #[macro_use]

src/ser.rs

@@ -10,7 +10,7 @@
 //!
 //! This module provides YAML serialization with the type `Serializer`.
 
-use std::{fmt, io};
+use std::{fmt, io, num, str};
 
 use yaml_rust::{yaml, Yaml, YamlEmitter};
 
@@ -73,7 +73,16 @@ impl ser::Serializer for Serializer {
  }
 
  fn serialize_f64(self, v: f64) -> Result<Yaml> {
- Ok(Yaml::Real(v.to_string()))
+ Ok(Yaml::Real(match v.classify() {
+ num::FpCategory::Infinite if v.is_sign_positive() => ".inf".into(),
+ num::FpCategory::Infinite => "-.inf".into(),
+ num::FpCategory::Nan => ".nan".into(),
+ _ => {
+ let mut buf = vec![];
+ ::dtoa::write(&mut buf, v).unwrap();
+ ::std::str::from_utf8(&buf).unwrap().into()
+ }
+ }))
  }
 
  fn serialize_char(self, value: char) -> Result<Yaml> {

tests/test_serde.rs

@@ -17,6 +17,7 @@ extern crate serde_yaml;
 extern crate unindent;
 use unindent::unindent;
 
+use std::f64;
 use std::fmt::Debug;
 use std::collections::BTreeMap;
 
@@ -73,6 +74,29 @@ fn test_float() {
  ---
  25.6");
  test_serde(&thing, &yaml);
+
+ let thing = 25.;
+ let yaml = unindent("
+ ---
+ 25.0");
+ test_serde(&thing, &yaml);
+
+ let thing = f64::INFINITY;
+ let yaml = unindent("
+ ---
+ .inf");
+ test_serde(&thing, &yaml);
+
+ let thing = f64::NEG_INFINITY;
+ let yaml = unindent("
+ ---
+ -.inf");
+ test_serde(&thing, &yaml);
+
+ let float: f64 = serde_yaml::from_str(&unindent("
+ ---
+ .nan")).unwrap();
+ assert!(float.is_nan());
 }
 
 #[test]