flow_debug: Debug With Flow Diagrams

Description

These functions are named after the base functions debug(), undebug() and debugonce(). flow_debug() will call flow_run(), with the same additional arguments, on all the following calls to f() until flow_undebug() is called. flow_debugonce() will only call flow_run() on the next call to f().

Usage

flow_debug(
  f,
  prefix = NULL,
  code = TRUE,
  narrow = FALSE,
  truncate = NULL,
  swap = TRUE,
  out = NULL,
  browse = FALSE
)
flow_debugonce(
  f,
  prefix = NULL,
  code = TRUE,
  narrow = FALSE,
  truncate = NULL,
  swap = TRUE,
  out = NULL,
  browse = FALSE
)
flow_undebug(f)

Arguments

function to debug

prefix

prefix to use for special comments in our code used as block headers, must start with "#", several prefixes can be provided

code

Whether to display the code in code blocks or only the header, to be more compact, if NA, the code will be displayed only if no header is defined by special comments

narrow

TRUE makes sure the diagram stays centered on one column (they'll be longer but won't shift to the right)

truncate

maximum number of characters to be printed per line

swap

whether to change var <- if(cond) expr into if(cond) var <- expr so the diagram displays better

out

a path to save the diagram to. Special values "html", "htm", "png", "pdf", "jpg" and "jpeg" can be used to export the objec to a temp file of the relevant format and open it, if a regular path is used the format will be guessed from the extension.

browse

whether to debug step by step (block by block), can also be a vector of block ids, in this case browser() calls will be inserted at the start of these blocks

Value

These functions return NULL invisibly (called for side effects)

Details

By default, unlike debug() and debugonce(), flow_debug() and flow_debugonce() don't trigger a debugger but only draw diagrams, this is consistent with flow_run()'s defaults. To browse through the code, use the browse argument.