动态 – Clojure Uni-Typed？

的迷人作品.其中写道：

And this is precisely what is wrong with dynamically typed languages: rather than affording the freedom to ignore types, they instead impose the bondage of restricting attention to a single type! Every single value has to be a value of that type, you have no choice! 

这 has come to mean uni-typed languages .(单一语言).

现在Clojure claims to be a dynamic language ：

Clojure is a dynamic programming language that targets the Java Virtual Machine (and the CLR, and JavaScript). It is designed to be a general-purpose language, combining the approachability and interactive development of a scripting language with an efficient and robust infrastructure for multithreaded programming. Clojure is a compiled language – it compiles directly to JVM bytecode, yet remains completely dynamic . Every feature supported by Clojure is supported at runtime.

“动态”意味着“可以在运行时与之交互”,而不是“没有类型”.

现在静态和动态之间的关键区别似乎是“我可以在编译时遇到类型失败吗？”

如果我写下面的Clojure代码：

(deftype circle-type [radius] )

(deftype square-type [side-length])


(defn def-check-type [new-symbol-type existing-symbol]
 (let [existing-symbol-type (type existing-symbol)]
    (cond 
     (= new-symbol-type existing-symbol-type) 
     (def new-symbol existing-symbol)
     :else (str "types didn't match: " new-symbol-type " : " existing-symbol-type))))

(println (def-check-type circle-type (square-type. 2)));)

然后在Leiningen编译它：

lein uberjar

然后我得到以下内容：

$lein uberjar
Compiling clojure-unittyped.core
types didn't match: class clojure_unittyped.core.circle-type : class clojure_unittyped.core.square-type

在动态语言中,这似乎是编译时的类型失败.

我的问题是：Clojure Uni-Typed？

编辑 – 我知道 core.typed – 这是一项很棒的工作.我问这个问题是分开的.

的单类型分类在实践中并不是很有用.

单类型理论很少揭示动态类型语言中编程的本质;它主要用于证明类型理论中存在“动态”类型.

像 Typed Racket 这样的项目被发明,正是为了发现和模拟 程序员 在这些语言中使用的隐式类型信息.通常类型都非常准确,并且表明还有很多东西比满足眼睛要多.