[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...
--
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~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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