Sorry for not answering long. After working a lot with new version of "bind" function I find it actually really useful. Just to avoid any possible hard-to-debug errors I try to stick to some good practices, like always specifying default values for formal parameters and calling "bind" with named arguments only.
And actually this feature reinvents http://www.nabble.com/Curry%3A-proposed-new-functional-rogramming%2C-er%2C-function.-td13535544.html#a13535544 :) I find myself operating a lot with list-of-lists-like structures, so this facility helps me really a lot. What about this one: combine <- function( ... ) { funs <- list( ... ) head <- funs[[1]] NULL -> funs[[1]] if( length(funs) > 0 ) function( ... ) do.call( combine, funs ) ( head( ... ) ) else head } It helps me to avoid lapplying multiple functions one after another, which was not really readable. Thus I came to writing code like this: sorting.predicate <- combine( pure.perf, bind( "[[", i="V11"), bind( quantile, 0.25 ) ) I wonder how bad is it? :) Regards, nosek Wacek Kusnierczyk wrote: > > nosek wrote: >> Hello, >> >> soon after my last posting to this thread I stumbled upon the do.call >> function and came to the very much the same version as yours. It is good! >> > > at least for the sort of tasks as in the examples below. but i haven't > tested it beyond those, and in r you shouldn't rely on intuition. > >> However, it looks that both name clashes and mixing keyword and >> positional >> styles in argument binding and function calls may lead to very drastic >> and >> cryptic errors. Therefore I find this "functional" style of programming >> not >> too reliable yet. >> > > would be interesting to see what sorts of very drastic and cryptic > errors you get. not that i would be surprised if something intuitively > correct does not if fact work. it might be a semantic weirdo, but it > might be that you use the solution in a way obviously destined to failure. > > vQ > > >> >> >> Wacek Kusnierczyk wrote: >> >>> czesc, >>> >>> looks like you want some sort of currying, or maybe partial currying, >>> right? anyway, here's a quick guess at how you can modify your bind, >>> and it seems to work, as far as i get your intentions, with the plot >>> example you gave: >>> >>> bind = function(f, ...) { >>> args = list(...) >>> function(...) do.call(f, c(list(...), args)) } >>> >>> plotlines = bind(plot, type='l') >>> plotlines(1:10, runif(10)) >>> >>> plotredlines = bind(plotlines, col="red") >>> plotredlines(runif(10)) >>> >>> # careful about not overriding a named argument >>> plotredpoints = bind(plotredlines, type="p") >>> plotredpoints(runif(10)) >>> >>> you may want to figure out how to get rid of the smart y-axis title. >>> is this what you wanted? >>> >>> pzdr, >>> vQ >>> >>> > > ______________________________________________ > 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. > > -- View this message in context: http://www.nabble.com/Partial-function-application-in-R-tp21487269p22474710.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
