import locks, threadpool, strutils
# compile with:
# nim c -r --threads:on -d:danger --gc:arc
{.experimental: "parallel".}

var
  lock: Lock
  a: array[20, string]

initLock lock

# Can do this explicitly with:
# proc process(b: ptr array[20, string], s: string) =
# or lazily with:
proc process(b: ptr, s: string) =
  withLock lock:
    b[][parseInt(s)] = s
  
when isMainModule:
  # could either explicitly define the pointer type
  # var ptra: ptr array[20, string] = addr(a)
  # or lazily with:
  var ptra = addr(a)
  parallel:
    for i in 0 ..< a.len:
      spawn process(ptra, $i)
  sync()
  echo a