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

[Uwe Ligges]

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
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