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Make an Active Binding

Source: R/py-classes.R
grapes-set-active-grapes.Rd

Make an Active Binding

Usage

sym %<-active% value

Arguments

sym

symbol to bind

value

A function to call when the value of sym is accessed.

Value

value, invisibly

Details

Active bindings defined in a %py_class% are converted to @property decorated methods.

See also

makeActiveBinding()

Examples

set.seed(1234)
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] 0.1137034
x
#> Evaluating function of active binding
#> [1] 0.6222994
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] 0.6092747
rm(x) # cleanup