CODEWITHSUNDEEP
r
Ron
Ron

Reputation: 991

What's similar to an #ifdef DEBUG in R?

I'm writing R code where I would like to have it run either in "non-debug" or "debug" mode. Under the debug mode, I would like the code to print-out runtime information.

In other languages, I would typically have some sort of print function that does nothing unless a flag is turned on (either for compilation or runtime).

For example, I can use #ifdef DEBUG (in compilation time), or set a debug level in run time.

What would be the equivalent way of doing this in R?

Upvotes: 7

Views: 1023

Answers (5)

Robert Sugar
Robert Sugar

Reputation: 151

Extending Richie's code:

also, you can check for the system environment variable DEBUG for initialization:

    isdbg <- function()
{
  if(exists(".DEBUG", envir = globalenv()))
  {
    return(get(".DEBUG", envir = globalenv()))
  } else #initialise from shell environment variable
  {
    debugmode <- !(toupper(Sys.getenv("DEBUG")) %in% c("", "FALSE", "0"))
    assign(".DEBUG", debugmode, envir = globalenv())
    return(debugmode)
  }
}

setdbg <- function(on = FALSE)
{
  old_value <- isdbg()
  .DEBUG <<- on
  invisible(old_value)
}

ifdbg <- function(x)
{
    if(isdbg()) x   
}

usage: setdbg(TRUE) #turn debug mode on setdbg(FALSE) #turn debug mode off

if(isdbg())
{
  #do some logging or whatever
}

or

ifdebug(...do something here...)

Upvotes: 1

Sean
Sean

Reputation: 3955

Another possibility is log4r

To quote this page:

log4r: A simple logging system for R, based on log4j

logr4 provides an object-oriented logging system that uses an API roughly equivalent to log4j and its related variants.

Upvotes: 0

Richie Cotton
Richie Cotton

Reputation: 121057

A slightly fancier version of Dirk's answer:

is_debug_mode <- function()
{
  exists(".DEBUG", envir = globalenv()) && 
    get(".DEBUG", envir = globalenv())
}

set_debug_mode <- function(on = FALSE)
{
  old_value <- is.debug.mode()
  .DEBUG <<- on
  invisible(old_value)
}

Usage is, e.g.,

if(is_debug_mode())
{
  #do some logging or whatever
}

and 

set_debug_mode(TRUE)   #turn debug mode on
set_debug_mode(FALSE)  #turn debug mode off

Upvotes: 4

nullglob
nullglob

Reputation: 7023

It might also be worth looking at the Verbose class in the R.utils package, which allows you very fine control for printing run-time information of various sorts.

Upvotes: 2

Dirk is no longer here
Dirk is no longer here

Reputation: 368201

Same thing, minus the preprocessor:

  • Define a global variable variable (or use an options() value)
  • Insert conditional code that tests for the variable
  • Works with your functions (adding ..., verbose=options(myVerbose)), in your packages, etc pp
  • I have also used it in R scripts (driven by littler) using the CRAN package getopt to pick up a command-line option --verbose or --debug.

Upvotes: 9

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