CSC/ECE 517 Fall 2013/ch1 1w21 w
CSC/ECE 517 Fall 2013/ch1 1w21 w
Ruby libraries to load objects of other languages at run time
This is an advanced topic. Libraries are being developed where Ruby gems can load libraries (and even native code) of other languages.A few open-source projects like FFI are currently working on this.
libffi is a foreign function interface library. It provides a C programming language interface for calling natively compiled functions given information about the target function at run time instead of compile time. It also implements the opposite functionality: libffi can produce a pointer to a function that can accept and decode any combination of arguments defined at run time. libffi is most often used as a bridging technology between compiled and interpreted language implementations. libffi may also be used to implement plug-ins, where the plug-in's function signatures are not known at the time of creating the host application. Notable users include Python, Haskell, Dalvik, F-Script, PyPy, PyObjC, RubyCocoa, JRuby, Rubinius, MacRuby, gcj, GNU Smalltalk, IcedTea, Cycript, Pawn, Squeak, Java Native Access, Racket,[2] Embeddable Common Lisp and Mozilla.[3] On Mac OS X libffi is commonly used with BridgeSupport, which provides programming language neutral descriptions of framework interfaces, and Nu which binds direct Objective-C access from Lisp. libffi has been widely ported and is released under a MIT license.
History
libffi, originally developed by Anthony Green, was inspired by the Gencall library from Silicon Graphics. Gencall was developed by Gianni Mariani, then employed by SGI, for the purpose of allowing calls to functions by address and creating a call frame for the particular calling convention. Anthony Green refined the idea and extended it to other architectures and calling conventions and open sourcing libffi.