Path: utzoo!attcan!uunet!lll-winken!ncis.llnl.gov!helios.ee.lbl.gov!pasteur!agate!bionet!csd4.milw.wisc.edu!nic.MR.NET!shamash!tank!uwvax!shorty!engber
From: engber@shorty.CS.WISC.EDU (Mike Engber)
Newsgroups: comp.sys.mac.programmer
Subject: Object Pascal
Summary: the with statement - is it safe?
Keywords: Object Pascal
Message-ID: <7096@spool.cs.wisc.edu>
Date: 27 Jan 89 01:36:13 GMT
Sender: news@spool.cs.wisc.edu
Reply-To: engber@shorty.cs.wisc.edu (Mike Engber)
Organization: U of Wisconsin CS Dept
Lines: 26

In the December '86 issue of MacTutor (also Apple Tech Report #6) Ken
Doyle wrote an articl on object Pascal in which he warns that using the
with statement on objects is dangerous in the same way using a with
statement on an unlocked handle is dangerous. This is because object
variables are really handles. (made to syntactically resemble normal
variables)

In the definition of Object Pascal they extended the definition of the
with statement to include its use with object. If Doyle's warning
applies, this seems pretty silly.

Note: I'm taking the point of view of 'vanilla' Object Pascal
programming, no HLock to help me out. I know the term 'vanilla' Object
Pascal may seem self contradictory, but Apple did get their definition
published in 'Structured Language World' so I assume they have some
interest in it being accepted elsewhere.

Also, for similar reasons Doyle warns against using an object's field as
a var parameter. The language definition seems to allow it, if it is a
problem then I have the same complaint again.

The answer to my question is probably compiler specific. A clever
compiler could have implented Object Pascal so that Doyle's warning
were not applicable.  I use LSP. Are you listening Rich?

-ME