R devel - Mar 1998 - Apropos names.

> To: R-devel@stat.math.ethz.ch
> Subject: Apropos names.
> From: Peter Dalgaard BSA <p.dalgaard@biostat.ku.dk>
> Date: 19 Mar 1998 18:44:14 +0100
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> (from R-core)
> > Btw, why can't object names contain a `@'?
Reserved for future use?
> Speaking of names. I've been thinking whether it would not at some
> point be wise to introduce namespaces into R. This would pretty
> obviously break a lot of S code, but it would also make it possible to
> avoid a lot of silly problems such as naming one's variables c, t, pt,
> df, rm, ... 
>
> A plan that might work relatively smoothly could involve:
>
> - Separate functions from variables. We already do that to some extent
>   ("looking for object of mode function...") [At the same time,
one
>   might get rid of everyone's favourite quirk: forgetting () and
>   thus listing the function instead of calling it. I know: basic
>   design, functions are just objects, etc., but really: Wouldn't it be
>   nicer to type view(ls) the few times you actually wanted to see its
>   contents?]
This has been done in common lisp and it's ugly.  Consider

	apply(x, 1, mean)

How do we indicate that this is the function called mean rather
than the non-function mean?  The single namespace makes it much
easier to think about functions as data.
> - All system functions and variables are really named something like
>   sys::c() i.e. we introduce a namespace separator ::.
>   Functions/variables that are intended for general use can be made
>   public, by a special call.
This is a definite possibility, but there are higher priorities at present.

	Ross

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Ross Ihaka <ihaka@stat.auckland.ac.nz> writes:

> 
> > Speaking of names. I've been thinking whether it would not at some
> > point be wise to introduce namespaces into R. This would pretty
> > obviously break a lot of S code, but it would also make it possible to
> > avoid a lot of silly problems such as naming one's variables c, t,
pt,
> > df, rm, ... 
> >
> > A plan that might work relatively smoothly could involve:
> >
> > - Separate functions from variables. We already do that to some extent
> >   ("looking for object of mode function...") [At the same
time, one
> >   design, functions are just objects, etc., but really: Wouldn't
it be
> >   nicer to type view(ls) the few times you actually wanted to see its
> >   contents?]
> 
> This has been done in common lisp and it's ugly.  Consider
> 
> 	apply(x, 1, mean)
> 
> How do we indicate that this is the function called mean rather
> than the non-function mean?  The single namespace makes it much
> easier to think about functions as data.
Ugh. You're right. An even clearer bit of ugliness is 

mean<-mean(x) # you'll be surprised at how many people will do that!
as.list(mean) # which one??

Hmm. Plan B:

class(c)<-"system"
class(ls)<-"system"
...

print.system<-function(...)warning(-something-)

"<-.system"<- function(...)error(-something-)

if you catch my drift?


-- 
   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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