Slinc: a scala c linking library for scala 3

Hi all,

I wanted to share some early progress I’ve made on a library for binding to C functions from Scala 3, which I’m calling Slinc (Scala link C).

It’s still a work in progress, so right now it’s only able to link to basic C functions, and it’s not well tested, but hopefully I can expand its capabilities in the coming month.

The library is powered by java 17’s foreign api incubator, a lot of macros, and cats Free. Binding a function looks like this:

C code:

struct div_t {
  int quot;
  int rem;

div_t div(int numer, int denom);

Scala code:

type div_t = Struct {
  val quot: int
  val rem: int

val div = NativeIO.function[(Int, Int) => div_t]("div")

NativeIO.scope( //scope handles allocation, and deallocates native memory upon the end of the scope
    result <- div(5,2)
    quot = result.quot.get
    rem = result.rem.get
  yield println(s"quotient:  $quot remainder: $rem")
).foldMap(NativeIO.impureCompiler) //only prints after compilation

There’s still a lot of work to do on it, and optimization to be done, but in my benchmarks it’s already beating JNA by a factor of ten on functions like the above, and it’s on par with JNR.


Very cool! I’m excited to try :smile: