Make an Active Binding
sym %<-active% valuesymbol to bind
A function to call when the value of sym is accessed.
value, invisibly
Active bindings defined in a %py_class% are converted to
@property decorated methods.
x %<-active% function(value) {
message("Evaluating function of active binding")
if(missing(value))
runif(1)
else
message("Received: ", value)
}
x
#> Evaluating function of active binding
#> [1] 0.8365774
x
#> Evaluating function of active binding
#> [1] 0.9449075
x <- "foo"
#> Evaluating function of active binding
#> Received: foo
x <- "foo"
#> Evaluating function of active binding
#> Received: foo
x
#> Evaluating function of active binding
#> [1] 0.5089196
rm(x) # cleanup