Advanced Debugging

In flow: View and Browse Code Using Flow Diagrams

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

This section introduces the browse argument of flow_run() and the functions flow_debug() and flow_debugonce()

browse

flow_run() runs a call and displays the logical path that was taken, but what if we'd like to walk through the code step by step, as we would by inserting a browser() call in our function's body or calling debug or debugonce on our function ?

In these cases we can use the browse argument, set it to TRUE and you'll be able to browse through the function as it's run. And refresh the diagram by typing d or the equivalent flow_draw()

flow_debug and flow_debugonce

flow_run is convenient to inspect the logic of a function that we call directly, sometimes we might want to inspect a call that's part of another function's body.

In this situation we can use flow_debug and flow_debug_once. These work a lot like debug and debugonce when using browse = TRUE.

library(flow)

flow_debugonce(factorial)
factorial5 <- function(){
  x <- 5L
  factorial(x)
}
factorial5()

flow documentation built on March 18, 2022, 6:22 p.m.