Bck2BrwsrMangling

From APIDesign

Revision as of 18:33, 26 January 2013

When translating the ByteCode to JavaScript the Bck2Brwsr project needs to face a common problem -- when translating a typed language (like Java) to untyped (like JavaScript) one needs to mange the names, so they continue to support method and field overloading.

Like JNI

There is a common mangling scheme specified by JNI for C and Bck2Brwsr mimics the specification as closely as possible. The mangling is based on underscore encoding substitution.

Fully Qualified Names

Fully qualified name uses '_' to separate package names and class name. The global virtual machine object vm has methods to obtain all classes. One can get reference to String as:

var clazz = vm.java_lang_String(false);

Methods

• There is "__" after name of a method and before its arguments
• return type is encoded first, parameters follow
• If there is an '_' in the name or argument segment, it gets replaced by "_1"
• array signatures start with '[' - such character is replaced by "_3"
• object signatures end with ';' - that character is replaced by "_2"

As a result to call method String.substring(int, int) - e.g. a method that return string and takes two integers as arguments -it be written as:

var s = "...";
var r = s.substring__Ljava_lang_String_2II(0, 5);

Static Method

When calling a static method, one first needs to obtain the name of a class. The class is made available in a global object called "vm". As such calling String.valueOf(10) is translated to:

var clazz = vm.java_lang_String(false);
var r = clazz.valueOf__Ljava_lang_String_2I(10);