[R] sub question

Gabor Grothendieck ggrothendieck at gmail.com
Sun Feb 1 13:03:09 CET 2009

On Sun, Feb 1, 2009 at 6:44 AM, Peter Dalgaard <p.dalgaard at biostat.ku.dk> wrote:
> 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...

Certainly that is one interpretation although from context it seems an unlikely
one since from that viewpoint +, [ and, in fact, everything is a variable.

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