Document extism.Json

README.md

@@ -1,5 +1,4 @@
-# Extism Python PDK
-![GitHub License](https://img.shields.io/github/license/extism/extism)
+# Extism Python PDK ![GitHub License](https://img.shields.io/github/license/extism/extism)
 ![GitHub release (with filter)](https://img.shields.io/github/v/release/extism/python-pdk)
 
 This project contains a tool that can be used to create [Extism Plug-ins](https://extism.org/docs/concepts/plug-in) in Python.
@@ -132,6 +131,28 @@ extism call plugin.wasm sum --input='{"a": 20, "b": 21}' --wasi
 # => {"sum":41}
 ```
 
+You can also specify your input and output types as dataclasses using `extism.Json`:
+
+```python
+from typing import Optional, List 
+from dataclasses import dataclass
+
+# ...
+
+@dataclass
+class User(extism.Json):
+  admin: bool
+  name: Optional[str]
+  email: str
+  addresses: List[Address]
+
+
+@extism.plugin_fn
+def reflect_user():
+  input = extism.input(User)
+  extism.output(input)
+```
+
 ### Configs
 
 Configs are key-value pairs that can be passed in by the host when creating a