I'm not enthusiastic about nonstandard evaluation and allowing functions to change state data. Currently, I use some of this in my own packages, but I'm planning to remove most of it.
But I did have some fun with your function. ---------- plt <- memify (plot) x <- 1:12 y1 <- seq (0, 18,, 12) y2 <- c ( 16.88, 16.04, 13.23, 13.88, 11.85, 9.61, 9.28, 5.81, 7.52, 3.40, 3.37, 0.07) #test 1 plt (x, y1, type="l") #test 2 plt (ylim = c (18, 0) ) #important econometric timeseries analysis plt (y=y2, main="Monthly NZ GDP (Millions)") ---------- Note: This data is not accurate. On Sat, Jan 2, 2021 at 9:20 AM Bert Gunter <bgunter.4...@gmail.com> wrote: > > Hi all: > > In the course of playing around with other issues, I wrote the following > little function that allows functions to keep state > and easily replay and update their state.(see comments after): > > memify <- function(f) > { > if (is.primitive(f)) { > cat("Cannot memify primitive functions.\n") > return(NULL) > } > if (!inherits(f, "function")) > stop("Argument must inherit from class 'function'") > arglist <- list() > structure( > function(...) { > m <- tryCatch( > as.list(match.call(f)[-1]), > error = function(e) { > warning("Bad function call; cannot update arguments\n") > return(NULL) > } > ) > nm <- names(m) > hasname <- nm != "" #logical index of named values > if (any(hasname)) { > if (anyDuplicated(nm, incomparables = "")) > warning("Duplicated names in call; only the first will be > used.") > arglist <<- modifyList(arglist, m[hasname]) ## this is what > does the job > } > do.call(f, modifyList(m, arglist)) > }, > class = c("memified", class(f))) > } > > Examples: > > x <- 1:9; y <- runif(9) > plt <- memify(plot) > x <- 1:9; y <- runif(9) > plt(x,y, col = "blue") ## plt "remembers" these arguments; i.e. keeps > state > plt( type = "b") ## all other arguments as previous > plt(col = "red") ## ditto > > So my question is: Beyond allowing one to easily change/add argument values > and replay when there are lots of arguments floating around, which we often > use an IDE's editor to do, is there any real use for this? I confess that, > like Pygmalion, I have been charmed by this idea, but it could well be > useless, By all means feel free to chastise me if so. > > 1. I am aware that many functions already have "update" methods to "update" > their results without re-entering all arguments -- e.g. lattice graphics, > glm, etc. > 2. Several packages -- rlang and R6 anyway -- but very likely more, do this > sort of thing and way more; the price is added complexity, of course. > 3. I realize also that keeping state would be a bad idea in many > circumstances, e.g. essentially changing documented defaults. > > Reply privately to praise or bury if you do not think this is of any > interest to readers of this list. Publicly is fine, too. If it's dumb it's > dumb. > > Cheers and best wishes for a better new year for us all, > > Bert Gunter > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.