Thanks Peter! That clarifies why it felt I was chasing ghosts these past days :) Thanks for the tip about coxph as well, there's some nice ideas to be discovered there.
Cheers Joris On Fri, Oct 3, 2014 at 3:02 PM, peter dalgaard <pda...@gmail.com> wrote: > > On 03 Oct 2014, at 14:32 , Joris Meys <jorism...@gmail.com> wrote: > > > Dear all, > > > > I'm updating a package regarding a new type of models, and I'm looking to > > extend the formula interface with two functions (L() and R() ) for > > construction of these models. I want to use as much of the formula > > interface as possible, and hoped to do something similarly to I(). > > > > I know the I() function does nothing more than add the class "AsIs". I've > > been browsing the source code of R for a couple of days now trying to > > locate where this class assignment gets translated into a specific > action, > > but i couldn't locate it. I've been as far as the internal C function > > modelframe. > > > > Any pointers on how I() is processed internally are greatly appreciated. > > It isn't... > > > E <- function(x)x > > x <- rnorm(10) > > y <- rnorm(10) > > lm(y~x+E(x^2)) > > Call: > lm(formula = y ~ x + E(x^2)) > > Coefficients: > (Intercept) x E(x^2) > 0.2757 0.1725 -0.3823 > > > The point is that special interpretation of operators never happens inside > function calls. I() is just a convenient do-nothing function call. > > If you want to add special operators, one place to look is in the handling > of specials for survival::coxph. > > > > > > Cheers > > Joris > > > > -- > > Joris Meys > > Statistical consultant > > > > Ghent University > > Faculty of Bioscience Engineering > > Department of Mathematical Modelling, Statistics and Bio-Informatics > > > > tel : +32 9 264 59 87 > > joris.m...@ugent.be > > ------------------------------- > > Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > -- > Peter Dalgaard, Professor, > Center for Statistics, Copenhagen Business School > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > Phone: (+45)38153501 > Email: pd....@cbs.dk Priv: pda...@gmail.com > > > > > > > > > -- Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Mathematical Modelling, Statistics and Bio-Informatics tel : +32 9 264 59 87 joris.m...@ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
