Dealing with call issues in `predict`

[moritzpschwarz]

As discussed with @gsucarrat, there remains an issue with call when using isat or arx in a sub-function:

## call issue with arx and isat

library(gets)
set.seed(123)
x <- rnorm(100)

estimate_module_fun <- function(x, ar){
  ar_test = ar 
  isat(x, ar = ar_test)
}


predict_module_fun <- function(obj){
  predict(obj, newmxreg = rnorm(10))
}

is_obj <- estimate_module_fun(x, ar = 2)
predict_module_fun(is_obj)


## same in arx

library(gets)
set.seed(123)
x <- rnorm(100)

estimate_module_fun <- function(x, ar){
  ar_test = ar 
  arx(x, ar = ar_test)
}


predict_module_fun <- function(obj){
  predict(obj, newmxreg = rnorm(10))
}

arx_obj <- estimate_module_fun(x, ar = 2)
predict_module_fun(is_obj)

This would need to be fixed in the predict functions. One potential fix could be by not relying on call as this only evaluates when executed - while making sure that it evaluates earlier (e.g. in isat.default() rather than later in predict.isat) could resolve this issue.