Re: [Rd] comment causes browser() to exit (PR#9063)
If I'm not mistaken, this works as documented. As an example (typed
directly into the Rgui console on WinXP):
R f - function() {
+ browser()
+ cat(I'm here!\n)
+ cat(I'm still here!\n)
+ }
R f()
Called from: f()
Browse[1] ## where to?
I'm here!
I'm still here!
which I think is what you saw. However:
R f()
Called from: f()
Browse[1] n
debug: cat(I'm here!\n)
Browse[1] ##
I'm here!
debug: cat(I'm still here!\n)
Browse[1]
I'm still here!
From ?browser:
c
(or just return) exit the browser and continue execution at the next
statement.
cont
synonym for c.
n
enter the step-through debugger. This changes the meaning of c: see the
documentation for debug.
My interpretation of this is that, if the first thing typed (or pasted) in
is something like a null statement (e.g., return, empty line, or comment),
it's the same as 'c', but if the null statement follows 'n', then it behaves
differently.
_
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor 3.1
year 2006
month 06
day01
svn rev38247
language R
version.string Version 2.3.1 (2006-06-01)
Andy
From: [EMAIL PROTECTED]
I'm trying to step through some code using browser(),
executing one line at a time.
Unfortunately, whenever I execute a comment line, the browser exits.
I previously reported a similar problem with blank lines.
These problems are a strong incentive to write poor code
-- uncommented code with no blank lines to improve
readability -- so that I can use browser() without it exiting
at inconvenient times.
Additional detail:
(1) I'm running R inside emacs, with R in one buffer and a
file containing code in another, using a macro to copy and
paste a line at a time from the file to the R buffer.
(2) The browser() call is inside a function.
Right now the lines I'm sending to the browser are not part
of the function, though usually they are.
--please do not edit the information below--
Version:
platform = i386-pc-mingw32
arch = i386
os = mingw32
system = i386, mingw32
status =
major = 2
minor = 3.1
year = 2006
month = 06
day = 01
svn rev = 38247
language = R
version.string = Version 2.3.1 (2006-06-01)
Windows XP Professional (build 2600) Service Pack 2.0
Locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
Search Path:
.GlobalEnv, package:methods, package:stats,
package:graphics, package:grDevices, package:utils,
package:datasets, Autoloads, package:base
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Re: [Rd] comment causes browser() to exit (PR#9063)
If I'm not mistaken, this works as documented. ...
Thanks for the response.
The behavior with return is as documented -- hence my earlier
enhancement request.
The behavior with a comment is contrary to the documentation, hence
this as a bug report.
On the second point -- help(browser) says:
Anything else entered at the browser prompt is interpreted as an R
expression to be evaluated in the calling environment: ...
whereas the actual behavior is to interpret a comment as equivalent to c,
and to exit the browser.
On the first point -- I would like to argue that the behavior of
return (and comments) should be changed, at least as a user option.
Here is a typical piece of code from a function; note the use of
comments and blank lines to improve readability:
# If statistic isn't a function or name of function or expression,
# store it as an expression to pass to fit.func.
substitute.stat - substitute(statistic)
if(!is.element(mode(substitute.stat), c(name, function)))
statistic - substitute.stat
# Get name of data.
data.name - substitute(data)
if(!is.name(data.name))
data.name - data
is.df.data - is.data.frame(data)
# How many observations, or subjects if sampling by subject?
n - nObservations - numRows(data) # n will change later if by subject
# Save group or subject arguments?
if(is.null(save.subject)) save.subject - (n = 1)
if(is.null(save.group)) save.group - (n = 1)
If I now stick a browser() in that function, and throw a line at a
time from the source file to R, it exits whenever I throw a blank line
or comment. I try to remember to skip the blank lines and comments,
but I sometimes forget, and get very annoyed when I have to start over.
I could use c in some contexts, but not others:
* I often want to evaluate code that is not part of the
defined function.
* I sometimes change objects and want to go evaluate some lines
that were previously evaluated.
In the enhancement request I requested an option to turn off the current
behavior of return. I personally would just change the default behavior,
and have both blank lines and comments do nothing. This is simpler, and
people can always use c to quit the browser.
This behavior of browser() is the most annoying thing I've found
about using R. As I anticipate using R a lot in the future, I would
appreciate very much if it is changed. I spent a fair amount of time
trying to see if I could change it myself, but gave up.
Tim Hesterberg
Andy Liaw wrote:
If I'm not mistaken, this works as documented. As an example (typed
directly into the Rgui console on WinXP):
R f - function() {
+ browser()
+ cat(I'm here!\n)
+ cat(I'm still here!\n)
+ }
R f()
Called from: f()
Browse[1] ## where to?
I'm here!
I'm still here!
which I think is what you saw. However:
R f()
Called from: f()
Browse[1] n
debug: cat(I'm here!\n)
Browse[1] ##
I'm here!
debug: cat(I'm still here!\n)
Browse[1]
I'm still here!
From ?browser:
c
(or just return) exit the browser and continue execution at the next
statement.
cont
synonym for c.
n
enter the step-through debugger. This changes the meaning of c: see the
documentation for debug.
My interpretation of this is that, if the first thing typed (or pasted) in
is something like a null statement (e.g., return, empty line, or comment),
it's the same as 'c', but if the null statement follows 'n', then it behaves
differently.
_
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor 3.1
year 2006
month 06
day01
svn rev38247
language R
version.string Version 2.3.1 (2006-06-01)
Andy
From: [EMAIL PROTECTED]
I'm trying to step through some code using browser(),
executing one line at a time.
Unfortunately, whenever I execute a comment line, the browser exits.
I previously reported a similar problem with blank lines.
These problems are a strong incentive to write poor code
-- uncommented code with no blank lines to improve
readability -- so that I can use browser() without it exiting
at inconvenient times.
Additional detail:
(1) I'm running R inside emacs, with R in one buffer and a
file containing code in another, using a macro to copy and
paste a line at a time from the file to the R buffer.
(2) The browser() call is inside a function.
Right now the lines I'm sending to the browser are not part
of the function, though usually they are.
--please do not edit the information below--
Version:
platform = i386-pc-mingw32
arch = i386
os = mingw32
system = i386, mingw32
status =
major
[Rd] comment causes browser() to exit (PR#9063)
I'm trying to step through some code using browser(), executing one line at a time. Unfortunately, whenever I execute a comment line, the browser exits. I previously reported a similar problem with blank lines. These problems are a strong incentive to write poor code -- uncommented code with no blank lines to improve readability -- so that I can use browser() without it exiting at inconvenient times. Additional detail: (1) I'm running R inside emacs, with R in one buffer and a file containing code in another, using a macro to copy and paste a line at a time from the file to the R buffer. (2) The browser() call is inside a function. Right now the lines I'm sending to the browser are not part of the function, though usually they are. --please do not edit the information below-- Version: platform = i386-pc-mingw32 arch = i386 os = mingw32 system = i386, mingw32 status = major = 2 minor = 3.1 year = 2006 month = 06 day = 01 svn rev = 38247 language = R version.string = Version 2.3.1 (2006-06-01) Windows XP Professional (build 2600) Service Pack 2.0 Locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252 Search Path: .GlobalEnv, package:methods, package:stats, package:graphics, package:grDevices, package:utils, package:datasets, Autoloads, package:base __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
