tl;

resource mm (f) [list(f)] { f = NULL; }

alloc(x;) {
  with mm when(true) {
    if(f==NULL) x = new();
    else { x = f; f = x->tl; }}
} [x|->]

dealloc(y) [y|->] {
  with mm when(true) { y->tl = f; f = y; }
}

proc(;y) {
  local x;
  alloc(x;);
  x->tl = y;
  dealloc(x);
}

main() {
  proc(42) || proc(13);
}