[R] can I call user-created functions without source() ?

[(Ted Harding)]

On 19-Jun-06 Rob Campbell wrote:
> Hi,
> 
> I have to R fairly recently from Matlab, where I have been used to
> organising my own custom functions into directories which are adding to
> the Matlab search path. This enables me to call them as I would one of
> Matlab's built-in functions. I have not found a way of doing the same
> thing in R. I have resorted to using source() on symlinks located in
> the
> current directory. Not very satisfactory.
> 
> I looked at the R homepage and considered making a "package" of my
> commonly used functions so that I can call them in one go:
> library(myFuncions, lib.loc="/path/to/library") Perhaps this is the
> only
> solution but the docs on the web make the process seem rather
> complicated--I only have a few script files I want to call! Surely
> there's a straightforward solution?
> 
> How have other people solved this problem? Perhaps someone has a simple
> "package skeleton" into which I can drop my scripts?
> 
> 
> Thanks,
> 
> Rob

There are pros and cons to this, but on the whole I sympathise
with you (having pre-R been a heavy matlab/octave user myself).

Unfortunately (from this perspective) R does not seem to have
an automatic "load-on-demand" facility similar to what happens
in matlab (i.e. you call a function by name, and R would search
for it in whatever the current search-path is, and load its
definition plus what else it depends on).

I have a few definitions which I want in every R session, so
I have put these in my ".Rprofile". But this is loaded from
my home directory, not from the directory where I was when I
started R, so it is the same every time. Again, one of the
conveniences of the matlab/octave approach is that you can
have a different sub-directory for each project, so if you
start work in a particular one then you have access to any
special definitions for that project, and not to others.

I'm no expert on this aspect of R, but I suspect that the way
start-up is organised in R does not fit well with the other
kind of approach. I stand to be corrected, of course ...

And others may well have formulated their own neat work-rounds,
so we wait eagerly to hear about these!

Best wishes,
Ted.

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Date: 19-Jun-06                                       Time: 11:25:15
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