V8 JavaScript引擎实现语言

Question

Looking from the wiki articale on V8 Javascript engine it says that it is written in C++ and JavaScript itself but what does that exactly mean?I mean What is written in C++ and what is in Javascript? And how these 2 languages work with each other?

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V8 JavaScript Engine

Developer(s) Google

Stable release 4.1.0[1] / March 3, 2015; 5 days ago

Development status Active

Written in C++, JavaScript

Operating system Cross-platform

Platform IA-32, x86-64, ARM, MIPS

Type JavaScript engine

License BSD Website code.google.com/p/v8

Answer 1

V8 is a C++ library that you can use to run JavaScript code. It can be used in any C++ application that wishes to execute JavaScript code. The most popular example is a web browser like Google Chrome, but its used in lots of different places.

From the V8 website:

What is V8? V8 is Google's open source high-performance JavaScript engine, written in C++ and used in Google Chrome, the open source browser from Google. It implements ECMAScript as specified in ECMA-262, 3rd edition, and runs on Windows XP and Vista, Mac OS X 10.5+, and Linux systems that use IA-32, ARM or MIPS processors. V8 can run standalone, or can be embedded into any C++ application.

Answer 2

Javascript files are here for runtime support ( arithmetics helpers, arrays, iterators...). I would think that C++ files and header are compiled to a native executable that supports a subset of JavaScript language. When the executable is started, his first action is to read the JS files, and so you have the full JavaScript language available.