After some more digging (grep alist R-devel/ ), I've come up with this,
tools:::as.alist.symbol(x)
sugar = function(fun, id = id){
ff - formals(fun)
if( id %in% names(ff))
stop(paste(id, is part of args(fun)))
new.arg - tools:::as.alist.symbol(id)
formals(fun) - c(unlist(ff), new.arg)
fun
}
foo = function(x, a=1){
x
}
sugar(foo)
sugar(foo, 'a')
sugar(sugar(foo))
sugar(foo, 'my.new.arg')
Best,
baptiste
2009/10/1 baptiste auguie baptiste.aug...@googlemail.com:
Dear list,
I have the following function,
sugar = function(fun, id = id){
ff - formals(fun)
if( id %in% names(ff))
stop(id is part of args(fun))
formals(fun) - c(unlist(ff), alist(id=))
fun
}
which one may use on a function foo,
foo = function(x){
x
}
sugar(foo) # results in the extended closure,
function (x, id)
{
x
}
Its limitation (other than not working with .Primitives) is the 'id'
tag that I add in the formals of fun(). I don't know how to create a
alist(id=) pairlist where id can be changed. I tried the usual bquote
and substitute approach but they don't seem to work here. I suppose I
could do something like,
parse(text = paste(alist(,id, =), sep=))
but this is usually not recommended.
Any ideas?
Best regards,
baptiste
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
