Add a serialization helper to put tables last

This should help serializing maps where it's unknown up front whether the tables
and/or values come first.

Closes #142

1 files changed, 30 insertions, 0 deletions

diff --git a/tests/tables-last.rs b/tests/tables-last.rs
new file mode 100644
index 0000000..d05c8f0
--- /dev/null
+++ b/tests/tables-last.rs
@@ -0,0 +1,30 @@
+#[macro_use]
+extern crate serde_derive;
+extern crate toml;
+
+use std::collections::HashMap;
+
+#[derive(Serialize)]
+struct A {
+    #[serde(serialize_with = "toml::ser::tables_last")]
+    vals: HashMap<&'static str, Value>,
+}
+
+#[derive(Serialize)]
+#[serde(untagged)]
+enum Value {
+    Map(HashMap<&'static str, &'static str>),
+    Int(i32),
+}
+
+#[test]
+fn always_works() {
+    let mut a = A { vals: HashMap::new() };
+    a.vals.insert("foo", Value::Int(0));
+
+    let mut sub = HashMap::new();
+    sub.insert("foo", "bar");
+    a.vals.insert("bar", Value::Map(sub));
+
+    toml::to_string(&a).unwrap();
+}