The Swig IDL tool for generating code from c++ header files

[dumganhar]

The problems of current binding-generator:

• Using libclang to parse c++ header files instead of parsing IDL files
• It's difficult for some developers to setup the tool environment which needs correct version of python & android ndk
• It's hard to extend its functionalities
• Its configuration file (tools/tojs/aaa.ini) is hard to understand
• It depends on specific android ndk version to generate code, the latest android ndk may not be compatible with bindings-generator
• The format of generated code is different on different systems (windows / macOS)
• The conversion system depends on c++ template now, user has to write c++ template to deal with JS <-> CPP conversions
• It's hard to support different backends
• It's hard to compare changes or handle conflicts in .ini file since plenty of configurations need to be written in a line
• No design documentation

Swig ( https://www.swig.org ) is strong enough for all our needs now. The main advantages are:

• Support many language backends, most languages you know.
• Support IDL which depends on C/C++ syntax
• Detailed documentation for usage and its internal implementation
• Very strong typemap system for easily implementing conversion between JS and cpp
• Lots of Built-in directives for handling complicated needs, like %typemap, %feature, %rename, %aggregate_check, %contract, %apply and so on.
• Swig itself is written by C ( swig core ) & C++ (swig module), performance should be good
• No other library dependences
• Variadic parameter support
• Support to bind c++ template
• And more, you could refer to https://www.swig.org/Doc4.0/SWIGDocumentation.html

Our needs of using Swig:

• Generate JS binding code that uses our ScriptEngine wrapper
• Generate .d.ts file for JS binding API
• Generate Serialization code for bitsery serialization library
• Generate emscripten binding code that uses embind
• Generate RenderGraph code
• Generate TS decorator relevant code
• Generate C++ API documentation
• Generate C++ reflection code

[dumganhar]

Problems need to be fixed:

• [x] Swig doesn't support to bind Nest Class like which in binding-generator
• [ ] Generate %attribute code in swig interface file according original TS file automatically.