Hello,
R 4.1.0 on Ubuntu 20.04, session info below.
I am not an English native speaker but in help("browser"), section
Arguments, argument expr, there is a wrong verb tense:
"invoked" should be "invoke", right?
expr
An expression, which if it evaluates to TRUE the debugger will invoked,
otherwise control is returned directly.
sessionInfo()
R version 4.1.0 (2021-05-18)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 20.04.2 LTS
Matrix products: default
BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.9.0
LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.9.0
locale:
[1] LC_CTYPE=pt_PT.UTF-8 LC_NUMERIC=C
[3] LC_TIME=pt_PT.UTF-8 LC_COLLATE=pt_PT.UTF-8
[5] LC_MONETARY=pt_PT.UTF-8 LC_MESSAGES=pt_PT.UTF-8
[7] LC_PAPER=pt_PT.UTF-8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=pt_PT.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] compiler_4.1.0
Thanks to all R Core Team members for their great work for all of us.
Hope this helps,
Rui Barradas
I'm also not a native speaker but my take is that a "be" is missing in the sentence and it should read An expression, which if it evaluates to TRUE the debugger will be invoked, otherwise control is returned directly. On Wed, Jul 28, 2021 at 11:52 PM Rui Barradas <ruipbarradas at sapo.pt> wrote:> > Hello, > > R 4.1.0 on Ubuntu 20.04, session info below. > > I am not an English native speaker but in help("browser"), section > Arguments, argument expr, there is a wrong verb tense: > > "invoked" should be "invoke", right? > > expr > An expression, which if it evaluates to TRUE the debugger will invoked, > otherwise control is returned directly. > > > > sessionInfo() > R version 4.1.0 (2021-05-18) > Platform: x86_64-pc-linux-gnu (64-bit) > Running under: Ubuntu 20.04.2 LTS > > Matrix products: default > BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.9.0 > LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.9.0 > > locale: > [1] LC_CTYPE=pt_PT.UTF-8 LC_NUMERIC=C > [3] LC_TIME=pt_PT.UTF-8 LC_COLLATE=pt_PT.UTF-8 > [5] LC_MONETARY=pt_PT.UTF-8 LC_MESSAGES=pt_PT.UTF-8 > [7] LC_PAPER=pt_PT.UTF-8 LC_NAME=C > [9] LC_ADDRESS=C LC_TELEPHONE=C > [11] LC_MEASUREMENT=pt_PT.UTF-8 LC_IDENTIFICATION=C > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > loaded via a namespace (and not attached): > [1] compiler_4.1.0 > > > > Thanks to all R Core Team members for their great work for all of us. > > Hope this helps, > > Rui Barradas > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel
>>>>> Rui Barradas >>>>> on Thu, 29 Jul 2021 07:52:02 +0100 writes:> Hello, > R 4.1.0 on Ubuntu 20.04, session info below. > I am not an English native speaker but in help("browser"), > section Arguments, argument expr, there is a wrong verb > tense: > "invoked" should be "invoke", right? > expr An expression, which if it evaluates to TRUE the > debugger will invoked, otherwise control is returned > directly. > sessionInfo() R version 4.1.0 ..... Thank you, Rui. Indeed, there's a typo there. I claim that it is a missing 'be': "be invoked" almost surealy was intended. As we are on the R-devel mailing list, however, let's dig and learn a bit more: Note that the *default* is `expr = TRUE` which is already a bit "special" for an "expression".. Let's try to understand what was meant --- NB a strategy I strongly recommend even if you're somewhat experienced :> ff <- function(x) { y <- x^2; browser("in ff():", expr = (y == 4)); y } > ff(1)[1] 1> ff(2)Called from: ff(2) Browse[1]> debug at #1: y Browse[2]> ls.str() x : num 2 y : num 4 Browse[2]> c [1] 4> ff(3)[1] 9>So indeed, it does behave as I expected. A further experiment, play with f2 <- function(x, e=1) { y <- x^2; browser("in ff():", expr = e); y } shows that 'evaluates to TRUE' is also not as precise as it could be, and even "wrong": 'expr = pi' also behaves as TRUE, and even 'expr = NA' behaves the same. I don't know when/how `expr` was introduced (probably taken from 'S / S+' ..), but to me it seems actually somewhat a misnomer because in that generalized sense, *every* argument passed to an R function is an "expression". Instead, what counts is that a low-level as.logical(expr) is not TRUE. So, yes, the documentation about `expr` definitely needs to be changed. Unless I get convincing suggestions for improvements, I'll commit \item{expr}{a \dQuote{condition}. By default, and whenever not false after being coerced to \code{\link{logical}}, the debugger will be invoked, otherwise control is returned directly.} (and also amend the formulation a bit later on the help page where expr is mentioned again). Martin > Thanks to all R Core Team members for their great work for > all of us. > Hope this helps, > Rui Barradas