String interpolation broken with recent gsubfn?

The last example was used, and now it is not. No string interpolation inside a function? Maybe this has something to do with the variable? Any suggestions?

library(gsubfn)
#R.Version() # I'm using 2.15.0, just upgraded from 2.13.something.

### dumb example of a function
g <- function() {for (a in 1:2) { print(paste('is a', a)) }}
g()

### same thing, outside a function, using string interpolation
for (a in 1:2) { fn$print('is a $a') }
rm(a)

### and now string interpolation inside a function
h <- function() {for (a in 1:2) { fn$print('is a $a') }}
h()

This last example tells me

Error in eval(expr, envir, enclos) : object 'a' not found