[R] inverse currying

[baptiste auguie]

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