我想更好地理解其中的区别。我在网上找到了很多解释,但它们都倾向于抽象的差异,而不是实际的含义。

Most of my programming experiences has been with CPython (dynamic, interpreted), and Java (static, compiled). However, I understand that there are other kinds of interpreted and compiled languages. Aside from the fact that executable files can be distributed from programs written in compiled languages, are there any advantages/disadvantages to each type? Oftentimes, I hear people arguing that interpreted languages can be used interactively, but I believe that compiled languages can have interactive implementations as well, correct?


当前回答

编译器和解释器做同样的工作:将一种编程语言翻译成另一种编程语言,通常更接近硬件,通常是直接可执行的机器代码。

Traditionally, "compiled" means that this translation happens all in one go, is done by a developer, and the resulting executable is distributed to users. Pure example: C++. Compilation usually takes pretty long and tries to do lots of expensive optmization so that the resulting executable runs faster. End users don't have the tools and knowledge to compile stuff themselves, and the executable often has to run on a variety of hardware, so you can't do many hardware-specific optimizations. During development, the separate compilation step means a longer feedback cycle.

Traditionally, "interpreted" means that the translation happens "on the fly", when the user wants to run the program. Pure example: vanilla PHP. A naive interpreter has to parse and translate every piece of code every time it runs, which makes it very slow. It can't do complex, costly optimizations because they'd take longer than the time saved in execution. But it can fully use the capabilities of the hardware it runs on. The lack of a separrate compilation step reduces feedback time during development.

But nowadays "compiled vs. interpreted" is not a black-or-white issue, there are shades in between. Naive, simple interpreters are pretty much extinct. Many languages use a two-step process where the high-level code is translated to a platform-independant bytecode (which is much faster to interpret). Then you have "just in time compilers" which compile code at most once per program run, sometimes cache results, and even intelligently decide to interpret code that's run rarely, and do powerful optimizations for code that runs a lot. During development, debuggers are capable of switching code inside a running program even for traditionally compiled languages.

其他回答

解释源代码相对于编译源代码的最大优势是可移植性。

如果你的源代码是编译的,你需要为你的程序运行在不同类型的处理器和/或平台编译不同的可执行文件(例如一个用于Windows x86,一个用于Windows x64,一个用于Linux x64,等等)。此外,除非您的代码完全符合标准,并且不使用任何特定于平台的函数/库,否则您实际上需要编写和维护多个代码库!

如果你的源代码是解释型的,你只需要编写一次,它就可以在任何平台上由合适的解释器解释和执行!它是便携!请注意,解释器本身是为特定平台编写和编译的可执行程序。

编译代码的一个优点是它向最终用户隐藏了源代码(可能是知识产权),因为您部署的不是人类可读的原始源代码,而是一个模糊的二进制可执行文件。

开始用“过去的冲击波”来思考

很久很久以前,有一个计算机王国 解释器和编译器。的优点引起了各种各样的争论 一个比另一个。当时的普遍意见是这样的:

解释器:快速开发(编辑和运行)。执行速度慢,因为每个语句都必须被解释为 每次执行的机器代码(想想这对于执行了数千次的循环意味着什么)。 编译器:开发(编辑、编译、链接和运行)缓慢。编译/链接步骤可能会花费大量时间)。快 来执行。整个程序已经是原生机器代码了。

运行时有一到两个数量级的差异 解释程序和编译程序之间存在性能差异。其他的区别 点,例如代码的运行时可变性,也有一些兴趣,但主要是 区别围绕着运行时性能问题。

今天的情况已经发展到这样的程度,编译/解释的区别是 几乎无关紧要。许多 编译语言调用的运行时服务并非如此 完全基于机器代码。而且,大多数解释型语言都被“编译”成字节码 之前执行。字节码解释器非常高效,可以与一些编译器生成的解释器相匹敌 从执行速度的角度来看代码。

典型的区别是编译器生成本机机器码,解释器读取源代码 使用某种运行时系统动态生成机器代码。 如今,经典的诠释者已所剩无几——几乎全部 编译成字节码(或其他一些半编译状态),然后在虚拟“机器”上运行。

语言本身既不编译也不解释,只有语言的特定实现才是。Java就是一个很好的例子。有一个基于字节码的平台(JVM)、一个本机编译器(gcj)和一个用于Java超集(bsh)的互用器。那么Java现在是什么呢?字节码编译,本机编译还是解释?

其他既编译又解释的语言有Scala、Haskell或Ocaml。每种语言都有一个交互式解释器,以及一个字节码或本机机器码的编译器。

所以一般来说,用“编译型”和“解释型”来划分语言并没有多大意义。

编译器和解释器做同样的工作:将一种编程语言翻译成另一种编程语言,通常更接近硬件,通常是直接可执行的机器代码。

Traditionally, "compiled" means that this translation happens all in one go, is done by a developer, and the resulting executable is distributed to users. Pure example: C++. Compilation usually takes pretty long and tries to do lots of expensive optmization so that the resulting executable runs faster. End users don't have the tools and knowledge to compile stuff themselves, and the executable often has to run on a variety of hardware, so you can't do many hardware-specific optimizations. During development, the separate compilation step means a longer feedback cycle.

Traditionally, "interpreted" means that the translation happens "on the fly", when the user wants to run the program. Pure example: vanilla PHP. A naive interpreter has to parse and translate every piece of code every time it runs, which makes it very slow. It can't do complex, costly optimizations because they'd take longer than the time saved in execution. But it can fully use the capabilities of the hardware it runs on. The lack of a separrate compilation step reduces feedback time during development.

But nowadays "compiled vs. interpreted" is not a black-or-white issue, there are shades in between. Naive, simple interpreters are pretty much extinct. Many languages use a two-step process where the high-level code is translated to a platform-independant bytecode (which is much faster to interpret). Then you have "just in time compilers" which compile code at most once per program run, sometimes cache results, and even intelligently decide to interpret code that's run rarely, and do powerful optimizations for code that runs a lot. During development, debuggers are capable of switching code inside a running program even for traditionally compiled languages.

编译语言是这样一种语言:程序一旦编译,就用目标机器的指令来表达。例如,源代码中的加法“+”操作可以直接转换为机器代码中的“ADD”指令。

解释型语言是指指令不直接由目标机器执行,而是由其他程序(通常用本机语言编写)读取和执行的语言。例如,相同的“+”操作将在运行时被解释器识别,然后调用它自己的“add(a,b)”函数,并使用适当的参数,然后执行机器代码“add”指令。

你可以在编译语言中做你在解释语言中可以做的任何事情,反之亦然——它们都是图灵完备的。然而,这两种方法在实施和使用方面都有优点和缺点。

我将完全概括(纯粹主义者原谅我!),但大致来说,以下是编译语言的优点:

通过直接使用目标计算机的本机代码获得更快的性能 有机会在编译阶段应用相当强大的优化

下面是解释型语言的优点:

更容易实现(编写好的编译器非常困难!!) 不需要运行编译阶段:可以直接“动态”执行代码 是否可以更方便地使用动态语言

注意,字节码编译等现代技术增加了一些额外的复杂性——这里发生的情况是,编译器的目标是一个与底层硬件不同的“虚拟机”。这些虚拟机指令可以在稍后阶段再次编译,以获得本机代码(例如,由Java JVM JIT编译器完成)。