[R] History pruning

[Ken Williams]

On 7/31/08 11:01 AM, "hadley wickham" <h.wickham at gmail.com> wrote:

> I think that would be a very hard task -

Well, at least medium-hard.  But I think significant automatic steps could
be made, and then a human can take over for the last few steps.  That's why
I was enquiring about "tools" rather than a complete solution.

Does R provide facilities for introspection or interrogation of expression
objects?  I couldn't find anything useful on first look:

> methods(class="expression")
no methods were found
> dput(expression(foo  <- 5 * bar))
expression(foo <- 5 * bar)
> str(expression(foo <- 5 * bar))
  expression(foo <- 5 * bar)
 

> it's equivalent to taking a
> long rambling conversation and then automatically turning it into a
> concise summary of what was said.  I think you must have human
> intervention.

It's not really equivalent, natural language has ambiguities and subtleties
that computer languages, especially functional languages, intentionally
don't have.  By their nature, computer languages can be turned into parse
trees unambiguously and then those trees can be manipulated.

But coincidentally I work in a Natural Language Processing group, and one of
the things we do is create exactly the kind of concise summaries you
describe. =)

-- 
Ken Williams
Research Scientist
The Thomson Reuters Corporation
Eagan, MN