From 94f6ea69296fdebbe91839295fa3419837d1cc32 Mon Sep 17 00:00:00 2001 From: Alexey Andreev Date: Thu, 12 Dec 2013 14:18:15 +0300 Subject: [PATCH] Create README.md --- README.md | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 README.md diff --git a/README.md b/README.md new file mode 100644 index 000000000..396440b15 --- /dev/null +++ b/README.md @@ -0,0 +1,41 @@ +TeaVM +===== + +What is TeaVM? +------------- + +In short, TeaVM gets a bytecode, running over JVM, and translates it to the JavaScript code, +which does exactly the same thing as the original bytecode does. +It is based on its cross-compiler which transforms `class` files to JavaScript. +But there is something more: + + * a sophisticated per-method dependency manager, which greatly reduces the JavaScript output; + * an optimizer capable of things like devirtualization, inlining, constant propagation, + loop invariant motion and many other; + * implementation of subset of core Java library; + +Advantages over GWT +------------------- + +You may notice that TeaVM idea is much similar to GWT. So why we need TeaVM instead of GWT? + +Unlinke GWT, TeaVM gets the compiled bytecode, not Java sources. +Thereby it **does not depend on a specific language syntax**. Even not on a specific language. +So, when the next Java version gets a new feature, you can use it in your source code +and TeaVM compiler remains unbroken. Also you may want thigs Scala, Kotlin or Ceilon. TeaVM supports them. + +To represent a source code, GWT uses abstract syntax trees (AST). +TeaVM uses control flow graph (CFG) of methods. CFG are much easier to optimize, +so TeaVM **applies aggressive optimizations** to you code to make it running faster. + +Advantages over JavaScript +-------------------------- + +JavaScript suffers of its dynamic typing. When you write a new code, dynamic typing accelerates +the development process, allowing you to write less boilerplate code. +But when you are to maintain a large code base, you may need static typing. +Also, it is not dynamic typing that really makes code short. +Good static typed languages can [infer variable types for you](http://en.wikipedia.org/wiki/Type_inference). +And they usually have a lot more useful features like [lambda functions](http://en.wikipedia.org/wiki/Lambda_function), +[lexical closures](http://en.wikipedia.org/wiki/Closure_%28computer_science%29), +[implicit type casting](http://en.wikipedia.org/wiki/Type_conversion#Implicit_type_conversion), etc.