类型系统

https://haxe.org/manual/type-system.html

Type Parameters

https://haxe.org/manual/type-system-type-parameters.html

Unification

https://haxe.org/manual/type-system-unification.html

Structural Subtyping

https://haxe.org/manual/type-system-structural-subtyping.html

类型推断

https://haxe.org/manual/type-system-type-inference.html