Correction: trace off course works when specifying the signature. so eg: trace(xyValues,tracer=browser,signature=c(object="RasterLayer", xy="matrix")) allows me to browse through the function. Should have specified the signature, I overlooked that. Still, if there's a manual on S4 that anybody likes to mention, please go ahead. I find bits and pieces on the internet, but haven't found an overview yet dealing with all peculiarities of these classes.
Cheers Joris On Fri, Jul 2, 2010 at 2:05 PM, Joris Meys <jorism...@gmail.com> wrote: > Dear all, > > I'm getting more and more frustrated with the whole S4 thing and I'm > looking for a more advanced summary on how to deal with them. Often I > get error messages that don't make sense at all, or the code is not > doing what I think it would do. Far too often inspecting the code > requires me to go to the source, which doesn't really help in easily > finding the bit of code you're interested in. > > Getting the code with getAnywhere() doesn't always work. Debug() > doesn't work. Using trace() and browser() is not an option, as I can't > find the correct method. > > eg : > library(raster) >> getAnywhere(xyValues) > A single object matching ‘xyValues’ was found > It was found in the following places > package:raster > namespace:raster > with value > > standardGeneric for "xyValues" defined from package "raster" > > function (object, xy, ...) > standardGeneric("xyValues") > <environment: 0x04daf14c> > Methods may be defined for arguments: object, xy > Use showMethods("xyValues") for currently available ones. >> showMethods("xyValues") > Function: xyValues (package raster) > object="Raster", xy="data.frame" > object="Raster", xy="SpatialPoints" > object="Raster", xy="vector" > object="RasterLayer", xy="matrix" > object="RasterStackBrick", xy="matrix" > > And now...? > > Is there an overview that actually explains how you get the > information you're looking for without strolling through the complete > source? Sorry if I sound frustrated, but this is costing me huge > amounts of time, to that extent that I rather write a custom function > than use one in an S4 package if I'm not absolutely sure about what it > does and how it achieves it. > > Cheers > Joris > > > -- > Joris Meys > Statistical consultant > > Ghent University > Faculty of Bioscience Engineering > Department of Applied mathematics, biometrics and process control > > tel : +32 9 264 59 87 > joris.m...@ugent.be > ------------------------------- > Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php > -- Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Applied mathematics, biometrics and process control tel : +32 9 264 59 87 joris.m...@ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.