What I Touched This Week 2017-02-12

This week I have worked on Lua API of Sentry using its Objective-C and Android client.

Add extern "C" around Lua C function in header compiled as Objective-C.
LuaJavaBridge - Lua 与 Java 互操作的简单解决方案是很详细的在 Cocos2d-x Lua 中调用 Java 方法的文章。不过有个地方已经过时了，就是 Java 的方法可以接收和返回 HashMap, 和 Vector (用 ArrayList 也可以）两种复杂变量的。有一些限制，调用的时候 Lua 不能传 nil，HashMap 对应的 Lua table 的 key 和 value 都会转成 String，在 Java 中可以强转成 HashMap<String, String>。Vector 对应的 Lua table 会当成是 list，所有成员也会转成 String，在 Java 中可以强转成 Vector<String>。对应的类型签名如下
- Ljava/util/HashMap;
- Ljava/util/Vector;
- Ljava/util/ArrayList;
Sentry-Android is an open source library to report errors in Android apps to Sentry. It is better than official Java library in my opinion.

Misc

Install gems using system Ruby when installed rbenv/rvm.
```
  sudo /usr/bin/gem install --bindir /usr/local/bin --no-env-shebang cocoapods
```
- --bindir: the default /usr/bin is not allowed to be modified.
  - --no-env-shebang: just use system Ruby explicitly.
webmachine: A REST-based system for building web applications, A RESTful framework for Erlang.
Iris, A go web framework.

In Lua, following two statements are identicated:

  require "xx." .. foo
  (require "xx.") .. foo