avoiding browser calls in R

问题:

I have an elaborate script that spans multiple functions (and files). For debugging purposes I need to embed browser calls into all sorts of nooks and crannies. When I presumably fix something, I want to run the whole thing without debugging, ergo avoiding browser calls because commenting out all browser calls would mean a considerable effort from my part. @mdsumner on R chat suggested running the script in non-interactive mode (i.e. using Rscript.exe on Windows) but I would benefit from having that done in my console, to be able to access for instance traceback. I have gone through browser docs and I can find no option that would come close to what I'm trying to achieve. Any suggestions?

回答1:

Here are three possibliities:

1) Overwrite browser command. Add this command to your global workspace to turn the browser commands off:

browser <- list

and to turn it back on

rm(browser)

This is probably the easiest but is a bit ugly due to the browser variable being left in the global environment.

The next two solutions are slightly longer but use options instead so that no new variables are introduced into the global environment. Also they are such that if no options are set then no debugging is done so you only have to set an option if you want debugging. The if solution may be faster than the expr solution although its likely not material.

2) Use expr= argument with option. Replace each browser command with:

browser(expr = isTRUE(getOption("Debug")))

and then define the "Debug" option to be TRUE to turn debugging on.

options(Debug = TRUE)

or set it to something else or remove it to turn debugging off:

options(Debug = NULL)

3) Use if with an option. Replace each browser command with:

if (isTRUE(getOption("Debug"))) browser()

and then set the Debug option or not as in the prior point.

回答2:

Define global logical value

debug_mode <- TRUE

and then instead of browser() use

if (debug_mode) browser()

回答3:

I think this just comes down to nuanced use of a debugging function. If you want to selectively control the use of browser(), put it inside an if that lets you enable or disable debugging for the function. When you want browser to be called, make that explicit like

myfun(x, debug =  TRUE)