branch doesn't pass attrs to function

[nacnudus]

This might be a feature request rather than a bug. It would be handy to branch depending on attributes.

library(simmer)

t1 <- create_trajectory("trajectory with a branch") %>%
  # Decide whether to branch or not, store in attribute
  set_attribute("branch", function() sample(1:2, 1)) %>%
  seize("server", 1) %>%
  # Branch or not depending on the attribute
  branch(function(attrs) attrs[["branch"]], merge=c(T, F), 
    create_trajectory("branch1") %>%
      timeout(function() 1),
    create_trajectory("branch2") %>%
      timeout(function() rexp(1, 3)) %>%
      release("server", 1)
  ) %>%
  release("server", 1)

env<-
  simmer() %>%
  add_resource("server", 1) %>%
  add_generator("patient", t1, at(0), mon = 2) %>%
  run()

# Error in eval(expr, envir, enclos) : 
#   argument "attrs" is missing, with no default

[Enchufa2]

Indeed. We didn't realise that the branch is the only activity without this functionality right now. Thanks for the report. I'll program this feature for the next release.

[Enchufa2]

Feature implemented in the dev-main branch. You can try it out with the following code:

library(simmer)

t1 <- create_trajectory("trajectory with a branch") %>%
  # Decide whether to branch or not, store in attribute
  set_attribute("branch", function() sample(1:2, 1)) %>%
  # Branch or not depending on the attribute
  branch(function(attrs) attrs[["branch"]], merge=c(T, T), 
    create_trajectory("branch1") %>%
     timeout(function() { print("hi, I'm the first branch"); 0 }),
    create_trajectory("branch2") %>%
     timeout(function() { print("hi, I'm the second branch"); 0 })
  ) %>%
  rollback(2, 10)

env <- simmer() %>%
  add_generator("patient", t1, at(0)) %>%
  run()

[nacnudus]

Brilliant, thank you. It works for me.