Barry Rowlingson wrote:
> Rolf Turner wrote: > > >> I don't follow what you aren't following .... It seems to me >> to be an eminently reasonable thing to want to do. Answers >> questions such as ``Was x modified since y was modified?'' > > > I wanted to have some sort of 'make'-like functionality in R. Why not just use make and generate a sequence of targets that come from renaming the .RData file saved after each step. Suppose > you have some complicated analysis that depends on several variables. If > you change one of them, you might not want to redo all the parts of the > analyses that dont depend on that change. Integrating this with Sweave > would be another gem, since parts of your Sweave document that might > take a long time to run might not need to run again if you've only > changed something after that point. If it takes an hour to generate a > dataset and two seconds to plot it, and you've made a change to the > plot, you dont want to re-run the whole data generation again when you > weave your document. > > >> I think I would make the modification data an ***attribute*** >> of the object, rather than sticking it in as a component. >> (The latter might mess up some vital aspect of the nature >> of the object.) >> >> The problem is to remember to date stamp each object each >> time it is modified .... > > > A while ago I attacked this problem at the C-code level. I found out > where R made assignments and tacked on a 'modified' attribute to the > object at that point. However it was a quick hack and it broke R quite > badly. One of the problems was that R objects were no longer identical > to assigned versions of themselves, and lots of tests broke. > > I think to be done properly it needs to be done at a lower level. Well, I guess what I'm suggesting is at a much higher level. Paul > > Barry > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
