[R] R design (was "Variable passed to function not used in function in select)

[Terry Therneau]

Rolf,
  Fair comments, mostly.   
  
> By and large the difficulties arise only in obscure contexts, when
> the user is trying to do something sophisticated. 

  But in the case at hand, the user was doing something simple, and got caught 
when the function tried to be overly clever.  That's rather unfair to him. The 
ongoing chain of examples and counterarguments got quite obscure though.
  
  
 > *Mostly* R is very easy to use and does exactly what the user would
 > expect.  
Less true than you think.  We've gotton so close and intimate that we forget how 
complicated the package actually is.  We lose track of how much we know.  
English spelling poses few conundrums to a literature major, the exceptions and 
special cases go below the level of conscious thought.  (No I'm not hinting that 
R is an inconsistent as English - no computer system is that bad.  Though come 
to think of it CMS came close).

  I have had this argument most often with SAS wizards who think they should use 
it in a beginners course, because its "simple to use".  But nothing whose 
printed documentation takes up 6 feet of shelf is particularly simple. R is not 
a small system either.
  
  	Terry