CLOP is an embedded language for separating an algorithm from the device specific optimizations that improve the performance of the algorithm on the device. The CLOP implementation uses the D programming language as its host language. The CLOP syntax is similar to, but not restricted by the syntax of D. CLOP fragments embedded in the application code allow to refer to the objects defined in the host application.

In its simplest use case, CLOP is a more convenient way to embed OpenCL kernels in a host application code.

// Needleman-Wunsch algorithm implementation.
// Use CLOP to generate OpenCL kernel and API calls.
void clop_nw()
{
  mixin(compile(q{
       int max3(int a, int b, int c)
       {
         int k = a > b ? a : b;
         return k > c ? k : c;
       }
       Antidiagonal NDRange(r : 1 .. rows, c : 1 .. cols) {
         F[r, c] = max3(F[r - 1, c - 1] + S[r, c],
                        F[r, c - 1] - penalty,
                        F[r - 1, c] - penalty);
       } apply(rectangular_blocking(BLOCK_SIZE, BLOCK_SIZE))
  }));
}