[R-pkg-devel] Browser Level for Conditional Function Parameter
On 20/08/2015 1:00 AM, Dario Strbenac wrote:
Good day, Why do I get a debug message and a change in browser level when I inspect the title variable ? For the comparison variable, it simply prints its value and remains at level 1.
This is an R-devel question, not an R-pkg-devel question. You get the break there because displaying title requires code to be evaluated (the default value is an expression), and the browser will break while evaluating that code. The "debug" message comes because it is on line 4 of your function that it is breaking. If it had been in a file that you sourced, it would give the line number from that file. Duncan Murdoch
aFunction <- function(comparison = c("within", "classifier", "selection"),
title = if(comparison[1] == "within") "Internal" else "Between")
{
browser()
require(ggplot2)
comparison <- match.arg(comparison)
ggplot(mtcars, aes(wt, mpg)) + geom_point() + ggtitle(title)
}
aFunction()
Browse[1]> title
debug at #4: [1] "Internal"
Browse[3]>
--------------------------------------
Dario Strbenac
PhD Student
University of Sydney
Camperdown NSW 2050
Australia
______________________________________________ R-package-devel at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel