Advanced R function call-CodePudding

all, this may sound dummy, but I need to understand some legacy R code while I know nothing of it. I hope someone could give me some hint on what's going on below:

g = if (calc.tstat){
function(...) FUN(...)} else 
{function(...) FUN(..1)}

These 3 lines are part of a function (famamacb) called by below:

temp <- famamacb(include = include, 
               function(coef) list(tseries.tstat = apply(coef,2, cumtstat, na.rm = T, i = 
match(rownames(coef), rownames(time.weight)))))

My understanding is FUN(...) refers to the function(coef), which generates a list. Could someone correct me if I'm wrong? But what does FUN(..1) do then?

Thanks much in advance!

CodePudding user response：

..1 refers to the first element from the variable number of arguments supplied through the ellipsis argument (see also help("...") for more information).

Here is a minimal example, showing how ..2 refers to the second element from the arguments supplied through ....

f <- function (x, ...) return(c(x, list(..2)))

f("zero", "one", "two")
#[[1]]
#[1] "zero"
#
#[[2]]
#[1] "two"