Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!brux
From: brux@cs.utexas.edu (Mark Brucks)
Newsgroups: comp.sys.mac.hypercard
Subject: scope rules for scripts
Keywords: hypertalk, messages, scope
Message-ID: <16488@cs.utexas.edu>
Date: 4 Jan 91 04:39:06 GMT
Organization: UTexas CS Dept, Austin, Texas
Lines: 25

I want to send a message from card "two" to card "one", and have
card "one" update information in its fields.  Here is an simple
card script for card "one" (the card receiving the doit message):

on doit arg1, arg2
  put arg1 & arg2 after card field "field 1" of card "one"
  put card field "field 1" of card "one" & "foobar" into card field "field 2"
end doit

The first line of the script works perfectly.  However, the second
line generates an error message "No such card".  What gives?

I realize that the current card doesn't change when a message is
sent, so that means that references to field "field 1" in the above
script default to fields of card "two" (the card sending the message).
That is why I have referenced card "one" explicitly, even though the
script belongs to card "one".  This kind of scoping seems a bit
bizarre to me, and I can't find any explanation in the HC Script
Lang. Guide.  This notion of the current card not changing when
a message is sent seems to suspend the usual scoping rules.  Is
this right?  If so, is there some mysterious advantage to this
that I haven't discovered?

Anyone care to explain this to an experienced programmer who
is new to HyperTalk.  Thanks.