[R] passing a function as an argument using lazy loading

Uwe Ligges
Sun, 14 Mar 2010 14:43:36 -0000

On 10.03.2010 13:26, Mark Heckmann wrote:
> I have the following function that makes use of lazy loading.


I guess you mean *lazy evaluation* rather than *lazy loading* (as used
in loading functions or data from the package databases).


> foo <- function(x=2*y, y=x/2) cat(x,y)
>
> Now I want to be able to modify it like below:
>
> foo(y=x/3)


You really want to *modify* the list of formal arguments like that or do
you want to *call* it like that?


> Of course, this does not work as the object x is not known.

Right.


> Still I
> would like to be able to pass a function as an argument that is
> evaluated using lazy loading.

If you rephrase your question more exactly and give a more elaborated
example where you want to make use of it, we may be able to help, but I
do not want to answer based on speculations here.

Best,
Uwe Ligges



> Can someone help?
>
> Thanks,
> Mark
> ???????????????????????????????????????
> Mark Heckmann
> Dipl. Wirt.-Ing. cand. Psych.
> Vorstra?e 93 B01
> 28359 Bremen
> Blog: www.markheckmann.de
> R-Blog: http://ryouready.wordpress.com
>
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