[R] sub question

Peter Dalgaard p.dalgaard at biostat.ku.dk
Sun Feb 1 12:44:43 CET 2009

Gabor Grothendieck wrote:
> On Sat, Jan 31, 2009 at 6:01 PM, Wacek Kusnierczyk
th some additional boring pedantry wrt. ?gsubfn, which says:
>> " If 'replacement' is a formula instead of a function then a one
>>     line function is created whose body is the right hand side of the
>>     formula and whose arguments are the left hand side separated by
>>     '+' signs (or any other valid operator).  The environment of the
>>     function is the environment of the formula.  If the arguments are
>>     omitted then the free variables found on the right hand side are
>>     used in the order encountered.  "
>> to my little mind, all of 'paste', 'rep', 'nchar', and 'x' in the
>> example above are *free variables* on the right of the formula.  you
> The first three are functions, not variables.

They are still free variables, subject to the same rules of variable 
lookup. Wacek is right: The RHS is scanned recursively for objects of 
mode "name" _except_ when they appear as function names (i.e. if 
subexpression e is mode "call", then forget e[[1]] and look at the 
arguments in as.list(e)[-1]. Not sure if this also happens if e[[1]] is 
not a name, e.g. in f(a)(b), do you get both a and b or just b?)

He is also right that it is pedantry...

    O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
   c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
  (*) \(*) -- University of Copenhagen   Denmark      Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)              FAX: (+45) 35327907

More information about the R-help mailing list