rule engine - first shot

apply_rules.R

imsbasics::clc()

apply_rules <- function(data, rules) {
  for (i in 1:length(rules)) {
    rules_now <- unlist(strsplit(rules[i], ", "))
    for (j in 1:length(rules_now)) {
      data[i] <- apply_rule(data[i], rules_now[j])
    }
  }
  return(data)
}

apply_rule <- function(data, rule) {
  rule <- get(rule)
  data <- rule(data)
  return(data)
}

rule1 <- function(data) {
  data * 2
}

rule2 <- function(data) {
  data + 1
}

rule3 <- function(data) {
  data ^ 3
}

# Interaktive Tests, einzelne Rules, gepiped.
library(magrittr)
data <- c(1,2,3)
apply_rule(data, "rule1")
apply_rule(data, "rule1") %>% apply_rule("rule2")
apply_rule(data, "rule2") %>% apply_rule("rule1")
apply_rule(data, "rule3")
apply_rule(data, "rule3") %>% apply_rule("rule2") %>% apply_rule("rule1")

# Hinterlegung der Rules für jedes Element, automatisches dispatching mit apply_rules()
df <- data.frame(
  data <- c(1,2,3),
  rules <- c("rule1", "rule1, rule2, rule3", "rule3, rule2"),
  stringsAsFactors = FALSE
)

apply_rules(df$data, df$rules)
# [1]   2 125  28