Wishlist: Navigate to "Index" page of help when no topic specified (PR#13860)

-----Original Message-----
From: Duncan Murdoch [mailto:murdoch at stats.uwo.ca]
Sent: Tuesday, August 04, 2009 5:06 PM
To: Steven McKinney
Cc: 'r-devel at stat.math.ethz.ch'; 'R-bugs at r-project.org'
Subject: Re: [Rd] Wishlist: Navigate to "Index" page of help when no
topic specified (PR#13860)

On 04/08/2009 7:33 PM, Steven McKinney wrote:

-----Original Message-----
From: Duncan Murdoch [mailto:murdoch at stats.uwo.ca]
Sent: Tuesday, August 04, 2009 8:03 AM
To: Steven McKinney
Cc: r-devel at stat.math.ethz.ch; R-bugs at r-project.org
Subject: Re: [Rd] Wishlist: Navigate to "Index" page of help when no
topic specified (PR#13860)

On 7/28/2009 6:30 PM, smckinney at bccrc.ca wrote:

Hi all,

When I install a new package, and don't yet know any function

names,

I have to play the "poor man's game" to get to the standard
help system "Index" page for the package:

You could complain to the package author or maintainer, who should

have

created a help alias with the package name so that ?survival would

give

you something useful.  But I would guess R 2.10.x or 2.11.x will do
that
automatically.

Duncan Murdoch

Unfortunately it happens frequently - hopefully I
don't have to complain so much - I'd rather figure
out code to get to the index page!

When you say "I would guess R 2.10.x or 2.11.x will do
that automatically" do you mean
?survival::
or some similar incantation
will take me to the Index or 00Index page?

I would guess package?survival will take you to a help page that is
similar to what you get now in the flat display from
library(help=survival).  Ideally it will have a link on it to the index
page.  It is possible that ?survival will work too; that may be more
controversial, because for many packages (e.g. boot) an alias like that
is already defined, pointing to something other than the package main
page.

Do I need to propose code or is it already
known how to do this within the R core group?

I doubt if code to do that would be accepted (since it will be
redundant
once the above changes are in place), but posting it to r-devel might
help people in the meantime.  You should look at the tools package,
which has a number of functions that are used by R for constructing the
help pages; there's probably something there that will let you
construct
a link to the index fairly easily.

Duncan Murdoch

Best
Steve McKinney

Poor Man's Game -=20
  Load new package;=20
  issue search() command;
  find position (say N) of loaded package;=20
  issue objects(pos =3D N) command;
  get name of a random function (san newFunction);=20
  issue ?newFunction command;
  scroll to bottom of page;=20
  click on the "Index" hyperlink

There are other variations, but they all involve this=20
long march to the Index page.


What I'd like to be able to do is enter the command

help(package =3D "survival")

or

?survival::

and get the usual hyperlinked help page displayed (the "00Index"

page)

instead of the static "text only" display or an error message

(for example, on Windows, this equates to invoking
"C:/PROGRA~1/R/R-29~1.1/library/survival/chm/00Index"
on Apple Mac,

"/Library/Frameworks/R.framework/Resources/library/survival/html/00Inde

x.ht=

ml"
etc.)


Details:
---------------

The help() function returns an object of
class "help_files_with_topic".
The object consists of a character vector
with several attributes.

PC:  Windows XP

library("survival")
foo <- help("aareg", package =3D "survival")
class(foo)

[1] "help_files_with_topic"

foo[1]

[1] "C:/PROGRA~1/R/R-29~1.1/library/survival/chm/aareg"

attributes(foo)

$call
help(topic =3D "aareg", package =3D "survival")

$pager
[1] "internal"

$topic
[1] "aareg"

$tried_all_packages
[1] FALSE

$type
[1] "chm"

$class
[1] "help_files_with_topic"

bar <- help("", package =3D "survival")
class(bar)

[1] "help_files_with_topic"

bar[1]

[1] NA

attributes(bar)

$call
help(topic =3D "", package =3D "survival")

$pager
[1] "internal"

$topic
[1] ""

$tried_all_packages
[1] FALSE

$type
[1] "chm"

$class
[1] "help_files_with_topic"

If I alter the character vector to
point to "00Index"

bar[1] <- "C:/PROGRA~1/R/R-29~1.1/library/survival/chm/00Index"
bar

I see exactly what I've been attempting to achieve.


Mac OS X:

foo <- help("aareg", package =3D "survival")
foo[1]

[1]

"/Library/Frameworks/R.framework/Resources/library/survival/html/aareg.

=

html"

attributes(foo)

$call
help(topic =3D "aareg", package =3D "survival")

$pager
[1] "/Library/Frameworks/R.framework/Resources/bin/pager"

$topic
[1] "aareg"

$tried_all_packages
[1] FALSE

$type
[1] "html"

$class
[1] "help_files_with_topic"

bar <- help("", package =3D "survival")
bar[1]

[1] NA

bar[1] <-

"/Library/Frameworks/R.framework/Resources/library/survival/htm=

l/00Index.html"

bar

Again I see exactly what I've been after.

Running R in Emacs on Mac OS X:

foo <- help(topic =3D "aareg", package =3D "survival")
foo[1]

[1]

"/Library/Frameworks/R.framework/Resources/library/survival/html/aareg.

=

html"

attributes(foo)

$call
help(topic =3D "aareg", package =3D "survival")

$pager
[1] "/Library/Frameworks/R.framework/Resources/bin/pager"

$topic
[1] "aareg"

$tried_all_packages
[1] FALSE

$type
[1] "html"

$class
[1] "help_files_with_topic"

bar <- help(topic =3D "", package =3D "survival")
bar[1]

[1] NA

bar[1] <-

"/Library/Frameworks/R.framework/Resources/library/survival/htm=

l/00Index.html"

bar

Help for '' is shown in browser /usr/bin/open ...
Use
        help("", htmlhelp =3D FALSE)
or
        options(htmlhelp =3D FALSE)
to revert.
Again, what I've been trying to achieve.

When a user loads a new library and doesn't yet know any function

names,

I think

help(package =3D "newLibrary")

or

?newLibrary::

should perform the above action whenever possible instead of
producing static help or an error message.

The "00Index" 'object' should be available for such use
whenever it exists. =20

I have not yet worked out all the coding details to make this

happen,

but before I do, am I missing some key point?  Any reasons why this
would be a Bad Idea?



Steven McKinney, Ph.D.

Statistician
Molecular Oncology and Breast Cancer Program
British Columbia Cancer Research Centre

email: smckinney +at+ bccrc +dot+ ca

tel: 604-675-8000 x7561

BCCRC
Molecular Oncology
675 West 10th Ave, Floor 4
Vancouver B.C.
V5Z 1L3
Canada