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John.Maindonald at anu.edu.au

2007-Sep-23 00:23 UTC

[Rd] html help fails for named vector objects (PR#9927)

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 R-2.5.1.


--please do not edit the information below--

Version:
platform = i386-apple-darwin8.10.1
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 (2007-09-22 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: john.maindonald at anu.edu.au
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.

Peter Dalgaard

2007-Sep-23 08:29 UTC

head link

[Rd] html help fails for named vector objects (PR#9927)

John.Maindonald at anu.edu.au 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, "try-error"))
        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 R-2.5.1.
>
>
> --please do not edit the information below--
>
> Version:
> platform = i386-apple-darwin8.10.1
> 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 (2007-09-22 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: john.maindonald at anu.edu.au
> 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.
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>   

-- 
   O__  ---- Peter Dalgaard             ?ster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)                  FAX: (+45) 35327907

Prof Brian Ripley

2007-Sep-23 08:50 UTC

head link

[Rd] html help fails for named vector objects (PR#9927)

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 MacOS-specific 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, John.Maindonald at anu.edu.au 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 R-2.5.1.
>
>
> --please do not edit the information below--
>
> Version:
> platform = i386-apple-darwin8.10.1
> 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 (2007-09-22 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: john.maindonald at anu.edu.au
> 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.
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
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

ripley at stats.ox.ac.uk

2007-Sep-23 08:50 UTC

head link

[Rd] html help fails for named vector objects (PR#9927)

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 MacOS-specific 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, John.Maindonald at anu.edu.au 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 R-2.5.1.
>
>
> --please do not edit the information below--
>
> Version:
> platform = i386-apple-darwin8.10.1
> 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 (2007-09-22 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: john.maindonald at anu.edu.au
> 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.
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
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

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