From tlumley at u.washington.edu  Sat Mar 14 09:58:25 2009
From: tlumley at u.washington.edu (Thomas Lumley)
Date: Sat, 14 Mar 2009 01:58:25 -0700 (PDT)
Subject: [Rd] surprising behaviour of names<-
In-Reply-To: <77EB52C6DD32BA4D87471DCD70C8D700DF10EE@NA-PA-VBE03.na.tibco.com>
Message-ID: <Pine.LNX.4.43.0903140158250.14976@hymn14.u.washington.edu>

On Fri, 13 Mar 2009, William Dunlap wrote:

> Would it make anyone any happier if the manual said
> that the replacement functions should not be called
> in the form
>   xNew <- `func<-` (xOld, value)
> and should only be used as
>   func(xToBeChanged) <- value
> ?

That was my reaction, too.  The discussion reminded me of old comp.lang.c threads about i=i++ and similar issues. The anomalies in
   xNew <- `func<-` (xOld, value) 
arise precisely because it isn't supposed to be used that way.

My other proposal for 'rigidly defined areas of doubt and uncertainty' has been the evaluation order of the *apply family (eg, does apply process the columns left to right, or right to left, or however it feels like?).


       -thomas

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle



[Rd] surprising behaviour of names<-
Thomas Lumley