Add serde deserialization.

doc/src/rust/serde.md

@@ -0,0 +1,63 @@
+Serialization and Deserialization of `Dynamic` with `serde`
+=========================================================
+
+{{#include ../links.md}}
+
+Rhai's [`Dynamic`] type supports serialization and deserialization by [`serde`](https://crates.io/crates/serde)
+via the [`serde`][features] feature.
+
+A [`Dynamic`] can be seamlessly converted to and from a type that implements `serde::Serialize` and/or
+`serde::Deserialize`.
+
+
+Serialization
+-------------
+
+Serialization by [`serde`](https://crates.io/crates/serde) is not yet implemented.
+
+It is simple to serialize a Rust type to `JSON` via `serde`, then use [`Engine::parse_json`]({{rootUrl}}/language/json.md) to convert
+it into an [object map].
+
+
+Deserialization
+---------------
+
+The function `rhai::de::from_dynamic` automatically converts a [`Dynamic`] value into any Rust type
+that implements `serde::Deserialize`.
+
+In particular, [object maps] are converted into Rust `struct`'s (or any type that is marked as
+a `serde` map) while [arrays] are converted into Rust `Vec`'s (or any type that is marked
+as a `serde` sequence).
+
+```rust
+use rhai::{Engine, Dynamic};
+use rhai::de::from_dynamic;
+
+#[derive(Debug, serde::Deserialize)]
+struct Point {
+    x: f64,
+    y: f64
+}
+
+#[derive(Debug, serde::Deserialize)]
+struct MyStruct {
+    a: i64,
+    b: Vec<String>,
+    c: bool,
+    d: Point
+}
+
+let engine = Engine::new();
+
+let result: Dynamic = engine.eval(r#"
+            #{
+                a: 42,
+                b: [ "hello", "world" ],
+                c: true,
+                d: #{ x: 123.456, y: 999.0 }
+            }
+        "#)?;
+
+// Convert the 'Dynamic' object map into 'MyStruct'
+let x: MyStruct = from_dynamic(&result)?;
+```