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Path: utzoo!watmath!clyde!cbosgd!ihnp4!inuxc!pur-ee!uiucdcsb!grunwald
From: grunwald@uiucdcsb.UUCP
Newsgroups: net.lang
Subject: Re: Path Pascal Release 0.9
Message-ID: <8900024@uiucdcsb.UUCP>
Date: Mon, 4-Feb-85 18:29:00 EST
Article-I.D.: uiucdcsb.8900024
Posted: Mon Feb  4 18:29:00 1985
Date-Received: Wed, 6-Feb-85 04:13:53 EST
References: <8900023@uiucdcsb.UUCP>
Lines: 41
Nf-ID: #R:uiucdcsb:8900023:uiucdcsb:8900024:000:993
Nf-From: uiucdcsb!grunwald    Feb  4 17:29:00 1985

Path Pascal uses Pascal as (a poor) vechicle for a concurrency language. Pascal
was chosen several years ago -- better choices could be made today. It's an
extension to Berkeley Pascal, so it has all their faults & extensions as well
as ones introduced by combining Path Expressions & processes. A sample program
with two processes (producer & consumer) follows. It simply uses a buffer to
pass '\0' .. '\127' between the two processes. Very stupid thing to do, but
it points out that this isn't intending to be yet another implementation of
Pascal.

program rw;

var
    buff : object
	path 1:(write;read) end;	(* ye olde path expression *)
	var datum : char;

	entry procedure write(x : char);
	begin datum := x; end;

	entry funciton read : char;
	begin read := datum; end;

	end (* object *);

process producer;
var i : integer;
begin
    for i := 0 to 127 do
	buff.write(chr(i));
end;

process consumer;
begin
    while (ord(buff.read) != 127) do ;
end;

begin
	producer;
	consumer;
end.