Portable Foreign Function Interface for R7RS schemes

Foreign function interface that is supported on multiple R7RS Sceheme implementations.

Note that this software is in alpha stage. That said the interface should not be changing anymore.

Any help in form of constructive advice and bug reports are appreciated.

Documentation or run mkdocs serve or see docs/.

Issue tracker

Maling lists

For documentation see retropikzel.neocities.org/r7rs-pffi or run mkdocs serve or see or docs/ directory.

Goals

• Support only R7RS implementations
  • Needs to have cond-expand and library support atleast (propably much more)
• Same interface on all implementations
  • Some things that are procedures on one implementation are macros on other, but they must behave the same

Non goals

• To support all R7RS implementations
• To have every possible FFI feature
• Compiling of C code at any point
  • That is no stubs, no C code generated by the library and so on

Supported implementations

• Sagittarius
  • Good support, recommended
• Guile
  • Good support, recommended
• Racket
  • Good support, recommended
• Chicken
  • Still needs work
• Gambit
  • Still needs work

Supported excepts callbacks

Callbacks not in FFI

These implementations do not have callback support on their FFI. If I'm wrong please let me know!

• STKlos
  • Still needs work
• Cyclone
  • Still needs work

Callbacks not implemented yet

• Kawa
  • Needs at least java version 22
  • Needs jvm flags:
    • --add-exports java.base/jdk.internal.foreign.abi=ALL-UNNAMED
    • --add-exports java.base/jdk.internal.foreign.layout=ALL-UNNAMED
    • --add-exports java.base/jdk.internal.foreign=ALL-UNNAMED
    • --enable-native-access=ALL-UNNAMED
  • Good support (otherwise), recommended

Support waiting for the implementation

• LIPS
  • Waiting for implementation to have cond-expand and library support
  • Will only work on nodejs
• Biwascheme
  • Waiting for implementation to have cond-expand and library support
  • Will only work on nodejs

Support needs to be investigated

• Gerbil
• Ypsilon
• Larceny
• Mosh
• Skint

Support maybe possible/dreaming about

• Airship
• Other gambit targets
  • Gambit compiles to different targets other than C too, for example Javascript. It would be cool and interesting to see if this FFI could also support some of those

Not supported

• Chibi
  • FFI requires C code
• MIT-Scheme
  • FFI requires C code
• tr7
  • FFI requires C code
• Gauche
  • FFI requires C code
• s7
  • No library support
  • Might have other things missing too
• Loko
  • Desires no C interop, I can respect that

Hacking

• You will need to have scheme_testrunner installed to run tests on large scale
  • You can also run them on your machine

Pull requests

Pull requests for bug fixes, additional implementation support and additional tests are appreciated. But please do not change the interface (library exports) and if you add support for implementation then all exported procedures of main.scm need to be implemented and tests must pass.