

help(letters, htmlhelp=TRUE) fails.
Under the Mac OSX gui, the message is 'Help for the topic "a" was not
found.' Under the version documented below, and under Windows, the
message is
"No documentation for 'a' in specified packages and libraries:"
repeated for all the elements of letters, then followed by
"you could try 'help.search("a")'",
again repeated for all elements of letters.
The outcome seems similar for any character vector (including matrix)
object, e.g. the matrix 'primateDNA' in the DAAGbio package.
The following have the expected result
help("letters", htmlhelp=TRUE)
help(letters, htmlhelp=FALSE)
The same result is obtained with R2.5.1.
please do not edit the information below
Version:
platform = i386appledarwin8.10.1
arch = i386
os = darwin8.10.1
system = i386, darwin8.10.1
status = beta
major = 2
minor = 6.0
year = 2007
month = 09
day = 22
svn rev = 42941
language = R
version.string = R version 2.6.0 beta (20070922 r42941)
Locale:
C
Search Path:
.GlobalEnv, package:testpkg, package:stats, package:graphics,
package:grDevices, package:utils, package:datasets, package:methods,
Autoloads, package:base
John Maindonald email: [hidden email]
phone : +61 2 (6125)3473 fax : +61 2(6125)5549
Centre for Mathematics & Its Applications, Room 1194,
John Dedman Mathematical Sciences Building (Building 27)
Australian National University, Canberra ACT 0200.
______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/rdevel


[hidden email] wrote:
> help(letters, htmlhelp=TRUE) fails.
>
> Under the Mac OSX gui, the message is 'Help for the topic "a" was not
> found.' Under the version documented below, and under Windows, the
> message is
>
> "No documentation for 'a' in specified packages and libraries:"
> repeated for all the elements of letters, then followed by
> "you could try 'help.search("a")'",
> again repeated for all elements of letters.
>
> The outcome seems similar for any character vector (including matrix)
> object, e.g. the matrix 'primateDNA' in the DAAGbio package.
>
> The following have the expected result
> help("letters", htmlhelp=TRUE)
> help(letters, htmlhelp=FALSE)
>
>
Not for me. I get the same thing with or without htmlhelp. (That IS what
I expected, though....)
The logic in help is
ischar < try(is.character(topic), silent = TRUE)
if (inherits(ischar, "tryerror"))
ischar < FALSE
if (!ischar)
topic < deparse(substitute(topic))
So a character argument implies that it contains the names of help
topics. That isn't quite what the documentation says, though:
topic: usually, the name on which documentation is sought. The name
may be quoted or unquoted (but note that if 'topic' is the
name of a variable containing a character string
documentation is provided for the name, not for the character
string).
It is the documentation that is wrong. We could implement what it says,
but then it would be a require considerable contortions to get help on a
topic stored in a variable (e.g., coming from a help field in a GUI).
It isn't clear to me that it should try all elements of a character
vector of length > 1. That looks like a bit of a booby trap to me 
what if it accidentally caught a variable with a few million elements? A
length check should be rather easy.
> The same result is obtained with R2.5.1.
>
>
> please do not edit the information below
>
> Version:
> platform = i386appledarwin8.10.1
> arch = i386
> os = darwin8.10.1
> system = i386, darwin8.10.1
> status = beta
> major = 2
> minor = 6.0
> year = 2007
> month = 09
> day = 22
> svn rev = 42941
> language = R
> version.string = R version 2.6.0 beta (20070922 r42941)
>
> Locale:
> C
>
> Search Path:
> .GlobalEnv, package:testpkg, package:stats, package:graphics,
> package:grDevices, package:utils, package:datasets, package:methods,
> Autoloads, package:base
>
> John Maindonald email: [hidden email]
> phone : +61 2 (6125)3473 fax : +61 2(6125)5549
> Centre for Mathematics & Its Applications, Room 1194,
> John Dedman Mathematical Sciences Building (Building 27)
> Australian National University, Canberra ACT 0200.
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/rdevel>

O__  Peter Dalgaard Ă˜ster Farimagsgade 5, Entr.B
c/ /'_  Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*)  University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~  ( [hidden email]) FAX: (+45) 35327907
______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/rdevel


On a normal R help system any version of help(letters) tries to give you
help on a, b, etc. This is intentional (although the documentation is
unclearly worded), and has been the case since at least R 2.0.0.
Some versions of help will display only the first topic.
If help(letters, htmlhelp=FALSE) does something else on your system, that
is a MacOSspecific bug since the topic selected should not depend on the
optional arguments.
What is unclear from the documentation is what should happen with
help(c("help", "help.search"))
It seems that for text help you get the first, for htmlhelp both.
There are two things we could do to help (apart from clarifying the
documentation):
1) If 'topic' is neither a name nor a character vector (e.g. an expression
like the last example) give an explicit error.
2) if topic is a character vector of length > 1, use the name.
On Sun, 23 Sep 2007, [hidden email] wrote:
> help(letters, htmlhelp=TRUE) fails.
>
> Under the Mac OSX gui, the message is 'Help for the topic "a" was not
> found.' Under the version documented below, and under Windows, the
> message is
>
> "No documentation for 'a' in specified packages and libraries:"
> repeated for all the elements of letters, then followed by
> "you could try 'help.search("a")'",
> again repeated for all elements of letters.
>
> The outcome seems similar for any character vector (including matrix)
> object, e.g. the matrix 'primateDNA' in the DAAGbio package.
>
> The following have the expected result
> help("letters", htmlhelp=TRUE)
> help(letters, htmlhelp=FALSE)
But the documented and actual results are the same, and different in the
two cases.
> The same result is obtained with R2.5.1.
>
>
> please do not edit the information below
>
> Version:
> platform = i386appledarwin8.10.1
> arch = i386
> os = darwin8.10.1
> system = i386, darwin8.10.1
> status = beta
> major = 2
> minor = 6.0
> year = 2007
> month = 09
> day = 22
> svn rev = 42941
> language = R
> version.string = R version 2.6.0 beta (20070922 r42941)
>
> Locale:
> C
>
> Search Path:
> .GlobalEnv, package:testpkg, package:stats, package:graphics,
> package:grDevices, package:utils, package:datasets, package:methods,
> Autoloads, package:base
>
> John Maindonald email: [hidden email]
> phone : +61 2 (6125)3473 fax : +61 2(6125)5549
> Centre for Mathematics & Its Applications, Room 1194,
> John Dedman Mathematical Sciences Building (Building 27)
> Australian National University, Canberra ACT 0200.
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/rdevel>

Brian D. Ripley, [hidden email]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/rdevel


On a normal R help system any version of help(letters) tries to give you
help on a, b, etc. This is intentional (although the documentation is
unclearly worded), and has been the case since at least R 2.0.0.
Some versions of help will display only the first topic.
If help(letters, htmlhelp=FALSE) does something else on your system, that
is a MacOSspecific bug since the topic selected should not depend on the
optional arguments.
What is unclear from the documentation is what should happen with
help(c("help", "help.search"))
It seems that for text help you get the first, for htmlhelp both.
There are two things we could do to help (apart from clarifying the
documentation):
1) If 'topic' is neither a name nor a character vector (e.g. an expression
like the last example) give an explicit error.
2) if topic is a character vector of length > 1, use the name.
On Sun, 23 Sep 2007, [hidden email] wrote:
> help(letters, htmlhelp=TRUE) fails.
>
> Under the Mac OSX gui, the message is 'Help for the topic "a" was not
> found.' Under the version documented below, and under Windows, the
> message is
>
> "No documentation for 'a' in specified packages and libraries:"
> repeated for all the elements of letters, then followed by
> "you could try 'help.search("a")'",
> again repeated for all elements of letters.
>
> The outcome seems similar for any character vector (including matrix)
> object, e.g. the matrix 'primateDNA' in the DAAGbio package.
>
> The following have the expected result
> help("letters", htmlhelp=TRUE)
> help(letters, htmlhelp=FALSE)
But the documented and actual results are the same, and different in the
two cases.
> The same result is obtained with R2.5.1.
>
>
> please do not edit the information below
>
> Version:
> platform = i386appledarwin8.10.1
> arch = i386
> os = darwin8.10.1
> system = i386, darwin8.10.1
> status = beta
> major = 2
> minor = 6.0
> year = 2007
> month = 09
> day = 22
> svn rev = 42941
> language = R
> version.string = R version 2.6.0 beta (20070922 r42941)
>
> Locale:
> C
>
> Search Path:
> .GlobalEnv, package:testpkg, package:stats, package:graphics,
> package:grDevices, package:utils, package:datasets, package:methods,
> Autoloads, package:base
>
> John Maindonald email: [hidden email]
> phone : +61 2 (6125)3473 fax : +61 2(6125)5549
> Centre for Mathematics & Its Applications, Room 1194,
> John Dedman Mathematical Sciences Building (Building 27)
> Australian National University, Canberra ACT 0200.
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/rdevel>

Brian D. Ripley, [hidden email]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/rdevel


There seems also to be a difference between the way 'help()' and '?'
handle 'topic' in some cases.
Consider:
lm < "aov"
The following all bring up help for 'lm':
?lm
?"lm"
help("lm")
This opens help for 'aov':
help(lm)
It seems that "?" doesn't care about quoting, but "help" does.
Did I miss something in the docs?
(If it matters, I'm using options(chmhelp=TRUE).)
> sessionInfo()
R version 2.6.0 beta (20070918 r42895)
i386pcmingw32
locale:
LC_COLLATE=English_Canada.1252; [snip]
attached base packages:
[1] stats graphics grDevices utils datasets methods base
 Peter Ehlers
Prof Brian Ripley wrote:
> On a normal R help system any version of help(letters) tries to give you
> help on a, b, etc. This is intentional (although the documentation is
> unclearly worded), and has been the case since at least R 2.0.0.
> Some versions of help will display only the first topic.
>
> If help(letters, htmlhelp=FALSE) does something else on your system, that
> is a MacOSspecific bug since the topic selected should not depend on the
> optional arguments.
>
> What is unclear from the documentation is what should happen with
>
> help(c("help", "help.search"))
>
> It seems that for text help you get the first, for htmlhelp both.
>
> There are two things we could do to help (apart from clarifying the
> documentation):
>
> 1) If 'topic' is neither a name nor a character vector (e.g. an expression
> like the last example) give an explicit error.
>
> 2) if topic is a character vector of length > 1, use the name.
>
>
> On Sun, 23 Sep 2007, [hidden email] wrote:
>
>> help(letters, htmlhelp=TRUE) fails.
>>
>> Under the Mac OSX gui, the message is 'Help for the topic "a" was not
>> found.' Under the version documented below, and under Windows, the
>> message is
>>
>> "No documentation for 'a' in specified packages and libraries:"
>> repeated for all the elements of letters, then followed by
>> "you could try 'help.search("a")'",
>> again repeated for all elements of letters.
>>
>> The outcome seems similar for any character vector (including matrix)
>> object, e.g. the matrix 'primateDNA' in the DAAGbio package.
>>
>> The following have the expected result
>> help("letters", htmlhelp=TRUE)
>> help(letters, htmlhelp=FALSE)
>
> But the documented and actual results are the same, and different in the
> two cases.
>
>> The same result is obtained with R2.5.1.
>>
>>
>> please do not edit the information below
>>
>> Version:
>> platform = i386appledarwin8.10.1
>> arch = i386
>> os = darwin8.10.1
>> system = i386, darwin8.10.1
>> status = beta
>> major = 2
>> minor = 6.0
>> year = 2007
>> month = 09
>> day = 22
>> svn rev = 42941
>> language = R
>> version.string = R version 2.6.0 beta (20070922 r42941)
>>
>> Locale:
>> C
>>
>> Search Path:
>> .GlobalEnv, package:testpkg, package:stats, package:graphics,
>> package:grDevices, package:utils, package:datasets, package:methods,
>> Autoloads, package:base
>>
>> John Maindonald email: [hidden email]
>> phone : +61 2 (6125)3473 fax : +61 2(6125)5549
>> Centre for Mathematics & Its Applications, Room 1194,
>> John Dedman Mathematical Sciences Building (Building 27)
>> Australian National University, Canberra ACT 0200.
>>
>> ______________________________________________
>> [hidden email] mailing list
>> https://stat.ethz.ch/mailman/listinfo/rdevel>>
>
______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/rdevel


On Sun, 23 Sep 2007, P Ehlers wrote:
> There seems also to be a difference between the way 'help()' and '?'
> handle 'topic' in some cases.
Yes, that is intentional. I didn't mention it (after deliberation) as the
bug report was about help(htmlhelp=TRUE) and not ?. I did mention
clarifying the documentation, which in my draft says
topic: usually, a name or character string specifying the topic for
which help is sought.
For 'help', if 'topic' is a lengthone character vector, the
topic is taken to be the value of the only element.
For '?' the 'topic' argument may also be a function call, to
ask for documentation on a corresponding method. See the
section on S4 method documentation.
but I am still tweaking.
> Consider:
> lm < "aov"
>
> The following all bring up help for 'lm':
> ?lm
> ?"lm"
> help("lm")
>
> This opens help for 'aov':
> help(lm)
>
> It seems that "?" doesn't care about quoting, but "help" does.
> Did I miss something in the docs?
No, as it is not in the docs as yet. The help page described what happens
for ?, not for help, e.g.
The 'topic' argument may also be a function call, to ask for
documentation on a corresponding method. See the section on
method documentation.
applies only to ? .
> (If it matters, I'm using options(chmhelp=TRUE).)
It will not if utils::help is being called.
>
>> sessionInfo()
> R version 2.6.0 beta (20070918 r42895)
> i386pcmingw32
>
> locale:
> LC_COLLATE=English_Canada.1252; [snip]
>
> attached base packages:
> [1] stats graphics grDevices utils datasets methods base
>
>  Peter Ehlers
>
> Prof Brian Ripley wrote:
>> On a normal R help system any version of help(letters) tries to give you
>> help on a, b, etc. This is intentional (although the documentation is
>> unclearly worded), and has been the case since at least R 2.0.0.
>> Some versions of help will display only the first topic.
>>
>> If help(letters, htmlhelp=FALSE) does something else on your system, that
>> is a MacOSspecific bug since the topic selected should not depend on the
>> optional arguments.
>>
>> What is unclear from the documentation is what should happen with
>>
>> help(c("help", "help.search"))
>>
>> It seems that for text help you get the first, for htmlhelp both.
>>
>> There are two things we could do to help (apart from clarifying the
>> documentation):
>>
>> 1) If 'topic' is neither a name nor a character vector (e.g. an expression
>> like the last example) give an explicit error.
>>
>> 2) if topic is a character vector of length > 1, use the name.
>>
>>
>> On Sun, 23 Sep 2007, [hidden email] wrote:
>>
>>> help(letters, htmlhelp=TRUE) fails.
>>>
>>> Under the Mac OSX gui, the message is 'Help for the topic "a" was not
>>> found.' Under the version documented below, and under Windows, the
>>> message is
>>>
>>> "No documentation for 'a' in specified packages and libraries:"
>>> repeated for all the elements of letters, then followed by
>>> "you could try 'help.search("a")'",
>>> again repeated for all elements of letters.
>>>
>>> The outcome seems similar for any character vector (including matrix)
>>> object, e.g. the matrix 'primateDNA' in the DAAGbio package.
>>>
>>> The following have the expected result
>>> help("letters", htmlhelp=TRUE)
>>> help(letters, htmlhelp=FALSE)
>>
>> But the documented and actual results are the same, and different in the
>> two cases.
>>
>>> The same result is obtained with R2.5.1.
>>>
>>>
>>> please do not edit the information below
>>>
>>> Version:
>>> platform = i386appledarwin8.10.1
>>> arch = i386
>>> os = darwin8.10.1
>>> system = i386, darwin8.10.1
>>> status = beta
>>> major = 2
>>> minor = 6.0
>>> year = 2007
>>> month = 09
>>> day = 22
>>> svn rev = 42941
>>> language = R
>>> version.string = R version 2.6.0 beta (20070922 r42941)
>>>
>>> Locale:
>>> C
>>>
>>> Search Path:
>>> .GlobalEnv, package:testpkg, package:stats, package:graphics,
>>> package:grDevices, package:utils, package:datasets, package:methods,
>>> Autoloads, package:base
>>>
>>> John Maindonald email: [hidden email]
>>> phone : +61 2 (6125)3473 fax : +61 2(6125)5549
>>> Centre for Mathematics & Its Applications, Room 1194,
>>> John Dedman Mathematical Sciences Building (Building 27)
>>> Australian National University, Canberra ACT 0200.
>>>
>>> ______________________________________________
>>> [hidden email] mailing list
>>> https://stat.ethz.ch/mailman/listinfo/rdevel>>>
>>
>

Brian D. Ripley, [hidden email]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/rdevel

