spawn send receive を実装

: test-receive
    receive
        { a X Pid } ( Pid X send test-receive )
        { b X Pid } ( Pid X X * send )
    ;receive
;

: test-send
    ' test-receive spawn
    dup
    { ' a 3 self } send
    { ' b 3 self } send
    {
        receive
          X ( X )
        ;receive
        receive
          Y ( Y )
        ;receive
    }
;

( test-send { 3 9 } == ) assert