From p.dalgaard@biostat.ku.dk  Mon Mar 13 19:49:02 2000
From: p.dalgaard@biostat.ku.dk (Peter Dalgaard BSA)
Date: 13 Mar 2000 20:49:02 +0100
Subject: [Rd] plot(1:10,c(1)$nothing)  yields index plot (PR#482)
In-Reply-To: Thomas Lumley's message of "Mon, 13 Mar 2000 11:27:42 -0800 (PST)"
References: <Pine.GSO.4.21.0003131116350.18281-100000@mail.biostat.washington.edu>
Message-ID: <x23dpuabwx.fsf@blueberry.kubism.ku.dk>

Thomas Lumley <thomas@biostat.washington.edu> writes:

> This turns out to be a bad idea, because we must be able to call plot(x)
> from other functions (with arbitrarily deep nesting), and it becomes very
> messy to trick plot() into handling the arguments correctly as they are
> passed from one function to another. 

Actually, S-plus has that problem, not R:

> f<-function(x,y)g(x,y)
> g<-function(x,y)missing(y)
> f(2)
[1] F

where R propagates missings just fine:

> f<-function(x,y)g(x,y)
> g<-function(x,y)missing(y)
> f(2)
[1] TRUE

but given the amount of ported code we have to deal with, we probably
have to be able to deal with NULLs being passed to signify absent
arguments. 

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907
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[Rd] plot(1:10,c(1)$nothing) yields index plot (PR#482)
Peter Dalgaard BSA