[R] keep.source.pkgs()

[Rolf Turner]

Thomas Lumley wrote:

> > However attr(arima,"source") was still NULL (and of course comments
> > were non-existant).  Apparently the functions in stats get
> > ***loaded*** from a binary file ``all.rda'' (in the
> > .../library/stats/R directory) rather than getting read in from ascii
> > files.  (One hesitates to ask ***why***, but .... why?)
> 
> Because R starts much faster that way.

	Ah-ha!!!  That indeed makes perfect sense.  Thank you.

> > So, some questions:
> >
> > 	1) Why do ``system'' packages, e.g. utils, behave differently
> > 	from ``optional'' packages?  I.e. why does the sequence
> >
> > 		. detach package
> > 		. set keep.source.pkgs=TRUE
> > 		. re-load package
> >
> > 	``work'', i.e. make the source available for functions in
> > 	optional packages but not for functions in system packages?
> 
> Because, as you noted, the base packages are stored in binary form.  This
> already speeds things up, and will have even more impact in 2.0.0 with
> "lazy loading" of functions.

	This CANNOT be the (complete) explanation, because the utils
	package behaves differently from the stats package.

	What I mean is, your explanation explains why you never
	get the source attributes ***at all*** with the stats
	package.

	It doesn't seem to me to explain why setting
	keep.source.pkgs=TRUE, detaching and reloading doesn't work
	for utils, whereas effectively setting keep.source.pkgs=TRUE
	``a priori'' and then loading utils ***does*** work.

	And ***nothing*** works with the stats package. Moreover in
	.../library/utils/R you find the ascii source file ``utils''
	and ***NOT*** a binary ``all.rda'' file.

> > I wonder if someone with better people skills and more patience
> > than Prof. Ripley would be so kind as to answer!
> 
>   When a Certain Guru rips strips off people (God knows he's done it to me
>   often enough) on this list, there's a damned good reason for it.
>    -- Rolf Turner (in a discussion about whether a friendly mailing list with
>       more `customer service' attitude than R-help was needed)
>       R-help (December 2003)

	Oh, far be it from me to disagree.  Especially with myself!
	I do not dispute the right to rip strips.  I just wanted a
	comprehensible answer to my question, that's all.

				cheers,

					Rolf Turner
					rolf at math.unb.ca