From d1b06f063385c2cfdb50c0109477f8128b248517 Mon Sep 17 00:00:00 2001
From: BLUELOVETH <blueloveTH@foxmail.com>
Date: Tue, 30 May 2023 14:49:53 +0800
Subject: [PATCH] ...

---
 README.md                    |  1 -
 README_zh.md                 |  1 -
 docs/features/differences.md | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 docs/features/differences.md

diff --git a/README.md b/README.md
index 420eaa67..d2e7a9e4 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,6 @@
 <img alt="GitHub" src="https://img.shields.io/github/license/blueloveth/pocketpy.svg?color=blue"></a>
 <a href="https://github.com/blueloveth/pocketpy/releases">
 <img alt="GitHub release" src="https://img.shields.io/github/release/blueloveth/pocketpy.svg"></a>
-<a title="Pub" href="https://pub.dev/packages/pocketpy" ><img src="https://img.shields.io/pub/v/pocketpy" /></a>
 </p>
 
 **English |** [**简体中文**](README_zh.md)
diff --git a/README_zh.md b/README_zh.md
index 1e2cbc53..43722093 100644
--- a/README_zh.md
+++ b/README_zh.md
@@ -6,7 +6,6 @@
 <img alt="GitHub" src="https://img.shields.io/github/license/blueloveth/pocketpy.svg?color=blue"></a>
 <a href="https://github.com/blueloveth/pocketpy/releases">
 <img alt="GitHub release" src="https://img.shields.io/github/release/blueloveth/pocketpy.svg"></a>
-<a title="Pub" href="https://pub.dev/packages/pocketpy" ><img src="https://img.shields.io/pub/v/pocketpy" /></a>
 </p>
 pocketpy是一个轻量级的Python解释器，为嵌入至游戏引擎而设计，基于C++17和STL。
 
diff --git a/docs/features/differences.md b/docs/features/differences.md
new file mode 100644
index 00000000..5713048b
--- /dev/null
+++ b/docs/features/differences.md
@@ -0,0 +1,33 @@
+---
+icon: dot
+title: Comparison with CPython
+order: 99
+---
+
+[cpython](https://github.com/python/cpython) is the reference implementation of the Python programming language. It is written in C and is the most widely used implementation of Python.
+
+## The design goal
+
+**pkpy aims to be an alternative to lua for
+game scripting, not cpython for general purpose programming.**
+
++ For syntax and semantics, pkpy is designed to be as close to cpython as possible.
++ For ecosystem and others, pkpy is not compatible with cpython.
+
+pkpy supports most of the syntax and semantics of python.
+For performance and simplicity, some features are not implemented, or behave differently.
+
+## Unimplemented features
+1. `**kwargs` in function definition.
+2. `__getattr__` and `__setattr__`.
+3. Descriptor protocol `__get__` and `__set__`. However, `@property` is implemented.
+4. `__slots__` in class definition.
+5. `import` module from a directory with `__init__.py`.
+6. One element tuple. `(1,)` is not supported.
+7. Unpacking in `list` and `dict` literals, i.e. `[1, 2, *a]`.
+8. Access the exception object in try..except.
+
+## Different behaviors
+1. positional and keyword arguments are strictly evaluated.
+2. When a generator is exhausted, `StopIteration` is returned instead of raised.
+3. `++i` and `--j` is an increment/decrement statement, not an expression.
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