[Rd] introspective capabilities
csr21 at cantab.net
Wed Sep 1 15:27:01 CEST 2010
Duncan Murdoch <murdoch.duncan at gmail.com> writes:
> On 27/08/2010 7:52 AM, Christophe Rhodes wrote:
>> Is there any way, from R code, to perform introspection as to where
>> certain names acquired their values?
> There's the "keep.source" option to source() and the optional
> "srcfile" argument to parse() that tell R to keep this information.
> If you haven't changed the default
> getOption("keep.source") from TRUE, then source will default to
> keeping it, and you can find the original location of a function
> definition for function f by looking in attr(body(f), "srcref"). See
> ?srcref for the format; there aren't a lot of user-level utility
> functions for working with this.
Thanks. This is enough for my immediate purposes: supporting
single-keystroke (M-.) jumping to source locations of functions.
> For packages, the relevant option is "keep.source.pkgs" at the time
> the package is installed.
Is there anything like a cross-referencing database within R? The
functionality I'm looking for here is to be able to name a function, and
come back with a list of functions (or srcrefs) where that name is
used. (I realise that this is not in general possible; just the
lexically-apparent cases would be enough).
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