[R] ?for

[Angel]

I thought I was getting to grips with it, until last reply from Prof Brian
Ripley's. At least in my Windows and Linux boxes
? paste("help")
opens the help for help (!?)
(But Marc is right, when you use emacs (in my Debian) instead of the shell
it gives the error he says, anybody knows why?)
For what I think I've learned, when you call ? it first evaluates the topic
and then asks for help on the result, i.e. if you put a function after ? it
will call help on the return value of that function, if it is a for or other
type of flow control it will ask for help for each of the loop results. Is
this the explicit reply to my original answer??
Thanks,
Angel
----- Original Message -----
From: "Marc Schwartz" <MSchwartz at MedAnalytics.com>
To: "Prof Brian Ripley" <ripley at stats.ox.ac.uk>
Cc: "Ray Brownrigg" <ray at mcs.vuw.ac.nz>; <r-help at stat.math.ethz.ch>;
<angel_lul at hotmail.com>; <p.dalgaard at biostat.ku.dk>
Sent: Monday, November 17, 2003 9:58 PM
Subject: Re: [R] ?for


> On Mon, 2003-11-17 at 14:27, Prof Brian Ripley wrote:
> > Well ^C or ESC (on Windows GUI) is the answer I would give.
> >
> > On Tue, 18 Nov 2003, Ray Brownrigg wrote:
> >
> > > Peter Dalgaard <p.dalgaard at biostat.ku.dk> writes:
> > > >
> > > > Prof Brian Ripley <ripley at stats.ox.ac.uk> writes:
> > > >
> > > > > You have typed a syntactically incomplete statement: this is
explained in
> > > > > ?help.
> > > > >
> > > > > Hint: ?"for" and help("for") work.
> > > >
> > > > [Original question added back in:
> > > > On Sun, 16 Nov 2003, Angel wrote:
> > > >
> > > > > I have always been intrigued by why ?for (or ?if,?while,etc) leave
R
> > > > > wanting for more:
> > > > > > ?for
> > > > > +
> > > > > I know the help for these is in ?Control, but I sometimes make the
> > > > > mistake of typing ?for instead. What is R expecting me to say to
finish
> > > > > the statement?
> > > > ]
> > > > Further hint: ? is an operator, syntactically similar to + and -.
You
> > > > can apply operators to the result of a for loop. Consider for
example
> > > >
> > > > x <- 1; - for (i in 1:10) x <- x * i
> > > >
> > > > (? has special semantics, but that is not noticed at parse time).
> > > >
> > > Unfortunately the original question still hasn't been answered
> > > explicitly, not even in ?help.
> > > Try:
> > > > ?for
> > > + (i in 0) 0
> > > or:
> > > > ?if
> > > + (T) T
> > > or:
> > > > ?+
> > > + 0
> > >
> > > So you have to provide the rest of a syntactically complete statement.
> > >
> > > Just to see if you now understand exactly how ? works, what do you
> > > think:
> > > ? paste("help")
> > > will do?
> > >
> > > Ray Brownrigg
>
>
> R 1.8.1 Beta using gnome-terminal on Fedora Core 1 gives:
>
> > ? paste("help")
> help() for paste  is shown in browser /usr/bin/mozilla ...
> Use      help( paste , htmlhelp=FALSE)
> or       options(htmlhelp = FALSE)
> to revert.
>
>
> However, using ESS with emacs on the same platform gives:
>
> > ? paste("help")
>
> Error in help("paste(", htmlhelp = FALSE) :
> No documentation for 'paste(' in specified packages and libraries:
>   you could try 'help.search("paste(")'
>
>
> :-)
>
> Marc
>
>
>
>