R6RS portable environment access

(psystem *) provides system APIs such as libc access.

Prerequisite

This library requires (pffi). For convenience, it's also a submodule located on deps/pffi of this repository.

(psystem os): OS name

This library provides the name of the OS.

• *psystem:os-name*: Symbol of the operating system's name. The name shall be the same per implementations if they are running on the same platform.

(psystem libc): C API

This library provides access to libc so that users don't have to write the following common code:

(define *psystem:libc*
  (open-shared-object
   (case *psystem:os-name*
     ((Linux) "libc.so.6")
     ((Darwin) "libc.dylib")
     ((Windows) "msvcrt.dll")
	 ;; something else
     (else "libc.so"))))

It also provides commonly used C function bindings.

• *psystem:libc*: A PFFI shared object of libc.
• (psystem:malloc size): A binding for malloc. The returning value is a pointer.
• (psystem:free pointer): A binding for free. The given argument must be a pointer which is allocated by the psystem:malloc or other malloc on the same libc.

Supported implementations

Currently the following implemnetations are supported.

• Sagittarius Scheme (0.9.4 or later)
• Chez Scheme (v9.5)
• Larceny (1.3)

If the implemnetation supports SRFI 112, then it would work without modification.

How to add implementations

Currently, the only implementation dependent part is (psystem os) library. If your implementation doesn't support SRFI 112, then add a file under the lib/psystem/ with name of os.${implementation}.sls which is de-fact standard to dispatch library of R6RS implementations, and impelemnt the variable described above section.

For example, if you want to add SuperScheme which can only be run on Linux machine then the file would look like this:

The file name: os.superscheme.sls The content:

(library (psystem os)
    (export *psystem:os-name*)
	(import (rnrs))
(define *psystem:os-name* 'Linux)
)