R scope: force variable substitution in function without local environment

Question

I\'m defining functions in a loop and trying to force evaluation of a loop variable without having to carry around a private environment.

Example: a set of functions

Answer 1

Here are some approaches that use body<-

You could use bquote

handlers <- list()

for (i in 1:6) {
  handlers[[paste0('h', i)]] <- function () {}
  body( handlers[[paste0('h', i)]]) <- bquote(message(.(i)))
}

handlers$h1
## function () 
##   message(1L)

or substitute

for (i in 1:6) {
  handlers[[paste0('h', i)]] <- function () {}
  body( handlers[[paste0('h', i)]]) <- substitute(message(i), list(i=i))
}