Hello,
I would like to establish top level condition handlers and restarts, so
that I don't explicit calls to withCallingHandlers and withRestarts in
many places:
For example :
> customError
function( message ){
err <- simpleError( message )
class( err ) <- c( "customError", class( err) )
err
}
> withCallingHandlers( { signalCondition(customError( "ouch")) } ,
customError = function(e) cat( "gotcha : ", e$message, "\n" ) )
gotcha : ouch
NULL
I'd like to be able to do something like this:
> topLevelCallingHandlers( customError = function(e) cat( "gotcha : ",
e$message, "\n" ) )
> signalCondition( customError( "ouch") )
and the "customError" condition to be caught by the handler I set up
previously.
I tried modifying withCallingHandlers like this:
topLevelCallingHandlers <- function(...) {
handlers <- list(...)
classes <- names(handlers)
if (length(classes) != length(handlers))
stop("bad handler specification")
.Internal(.addCondHands(classes, handlers, .GlobalEnv, .GlobalEnv,
TRUE))
invisible( NULL )
}
> withCallingHandlers
function (expr, ...)
{
handlers <- list(...)
classes <- names(handlers)
parentenv <- parent.frame()
if (length(classes) != length(handlers))
stop("bad handler specification")
.Internal(.addCondHands(classes, handlers, parentenv, NULL,
TRUE))
expr
}
<environment: namespace:base>
but it does not work, probably because the handler stack is reset
somewhere.
Would it work if I poke into the RTopLevel.handlerstack instead of the
R_HandlerStack as .addCondHands is doing ?
R_Toplevel.handlerstack = R_HandlerStack;
R_Toplevel.restartstack = R_RestartStack;
R_GlobalContext = R_ToplevelContext = &R_Toplevel;
Romain
--
Romain Francois
Independent R Consultant
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
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