[R] Function call on every prompt

[Duncan Murdoch]

On 19/11/2010 10:31 AM, Marc Schwartz wrote:
> On Nov 19, 2010, at 9:23 AM, Barry Rowlingson wrote:
>
> >  Someone on stackoverflow.com was wondering how to display the current
> >  time in the R prompt. I could have swore there was a mechanism for
> >  hooking a function into R such that it is was called before the ">"
> >  prompt was given, but no amount of searching in R's docs, R's source,
> >  or RSiteSearch can find it.
> >
> >  I've searched for 'hook', 'event', 'signal', and various combinations
> >  of those with 'console', 'prompt', 'after' and 'before' with no joy.
> >  I'm sure other people have asked this on R-help before, but I can't
> >  find those messages either.
> >
> >  Have I been hallucinating or is my search-fu week this Friday?

Barry was probably remembering SweaveHook.

> >
> >  Barry
>
>
> Baz,
>
> What's wrong with:
>
> >  options(prompt = paste(format(Sys.time(), "%a %b %d %X %Y %Z"), ">"))
> Fri Nov 19 09:30:53 2010 CST>
> Fri Nov 19 09:30:53 2010 CST>
> Fri Nov 19 09:30:53 2010 CST>

That one doesn't get updated with every prompt.

Duncan Murdoch