Follow-up on the wish for a visibility flag with tryEval ? - R-devel

Sat, Mar 7, 2009 6:51 AM #

Dear list,

Did the wish for an official API for evaluating expressions while 
keeping an eye on the R_Visible flag (see:
https://stat.ethz.ch/pipermail/r-devel/2007-April/045258.html
) lead to something ?

I could not find a sign of it the current (R-2.8.1 and R-2.9-dev) R defines.


Thanks,


L.

Duncan Murdoch

Sat, Mar 7, 2009 2:26 PM #

On 07/03/2009 9:51 AM, Laurent Gautier wrote:

You should read the NEWS file, where you'll find withVisible mentioned.

Duncan Murdoch

Laurent Gautier

Sun, Mar 8, 2009 12:22 PM #

I guess that I should have been reminding that the thread referred to is 
mostly about C API-level utilities (and the subject for this thread 
should be mentioning more precisely *R_tryEval()* ).

Wrapping evaluation from C-level in an R-level withVisible() call is 
certainly possible if this is the only way to do it:

- a C-level utility function is probably becoming handy (and that's 
mostly what the wish is about, AFAIUI).

- the traceback has at least one added layer from the call to 
withVisible(); this is something supplementary to take care of when 
writing a GUI for example.

Those are possible reasons why the threads tells that withVisible() 
[R-level] is a temporary option, waiting for something like 
R_tryEvalWithVis() [C-level].


Can't I find any such C-level because there isn't any, or because I just 
missed it ?



Thanks,





L.

Duncan Murdoch wrote: