parallelfor.nim

# Here is a fun language thing I made for parallel for loops.  The syntax is:

# parallelFor(sequence, i, numProcs):
#        do something with sequence[i]


# Which gets translated by this code:

template parallelFor*[T](data:openarray[T], i:expr, numProcs:int, body : stmt) : stmt {.immediate.} =
    let numOpsPerThread = (data.len/numProcs).toInt
    proc fe(j:int) {.thread.} =
        for q in 0 .. numOpsPerThread-1:
            let i = j*numOpsPerThread+q
            body
    var thr: array[0..numProcs-1, TThread[int]]
    for j in 0 .. numProcs-1:
        createThread(thr[j], fe, j)
    joinThreads(thr)