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 two ways. They are the same except for the ## line in each:

formals<-

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

trace

handlers <- list()
f <- function() message(i)
for (i in 1:6) { 
   trace(f, bquote(i <- .(i)), print = FALSE) ##
   handlers[[paste0('h', i)]] <- f 
}