/* Mystify the client at the other end of the specified client socket by sending * some cryptic numbers. */ Method "Mystify_" is [ client : client socket | rng ::= a Mersenne Twister; Guard [ /* Allow fast reuse of the local address. */ client's address reusability := true; /* Send the size of the stream of mysterious numbers. */ howMany ::= 5 × rng's next [1..51]; Write <howMany> to client; /* Send some mysterious numbers. */ weirdNumbers ::= map 1 to howMany through [i : byte | rng's next byte]; Write weirdNumbers to client; ] ensure [Close client;]; ] : ⊤; /* At the present time, the spaces are required in the specification of an IP * address. This limitation will be removed once Avail has a backtracking * lexical scanner. * * Incidentally, port 0 represents a wildcard port; the system will choose a * suitable one. */ serverAddress ::= 127 . 0 . 0 . 1 : 0; /* Run the numbers station. The server stops automatically after mystifying * three clients. */ Method "Start Lincolnshire Poacher" is [ server ::= a server socket named "Lincolnshire Poacher"; Guard [ server's address reusability := true; Bind server to serverAddress; Repeat [ client ::= accept a new connection on server; Fork [Mystify client;]; ] 3 times; ] ensure [Close server;] ] : ⊤; /* Connect to the server, receive the mysterious numbers, and regurgitate them * to standard output as hyphen-separated quintets. */ Method "Be mystified" is [ client ::= a client socket named "amateur spy"; Guard [ client's address reusability := true; Bind client to 127 . 0 . 0 . 1 : 0; Connect client to serverAddress; expected ::= (read 1 byte from client)[1]; weirdNumbers ::= read expected bytes from client; /* Report the mysterious numbers. */ quintets ::= map 1 to |weirdNumbers| - 1 by 5 through [i : byte | weirdNumbers[i..i + 4]]; For each of quintets do [ q : <byte…|5> | Print: format "“①”-“②”-“③”-“④”-“⑤”\n" with unchecked q; ]; ] ensure [Close client;]; ] : ⊤; /* Run it! */ Start Lincolnshire Poacher; Repeat [Be mystified;] 3 times;