You might find it helpful to read http://adv-r.had.co.nz/Expressions.html, and look at pryr:: standardise_call().
Hadley On Tue, Apr 8, 2014 at 6:52 PM, Spencer Graves <spencer.gra...@structuremonitoring.com> wrote: > Hi, Bill: > > > Thanks for the reply. Unfortunately, I don't see how that solves the > example I gave of extracting "plot(x=0, y=1)" from tstFn <- > function()plot(0, 1). > > > As I noted, body(tstFn) returns "plot(0, 1)" as an "language" object > of class "call". My challenge is to convert that into something similar, > with explicit names for the arguments. > > > Any thoughts? > Spencer > > > > On 4/7/2014 3:18 PM, William Dunlap wrote: >> >> Look at match.call(). E.g., >> > f <- function(x, y = log2(x), ...) match.call() >> > f() >> f() >> > f(1, x=2, anotherArg=3, 4) >> f(x = 2, y = 1, anotherArg = 3, 4) >> or, using its 'definition' and 'call' arguments directly >> > match.call(function(x, y, ...)NULL, quote(foo(1, x=2, extraArg=3, >> 4))) >> foo(x = 2, y = 1, extraArg = 3, 4) >> > match.call(function(x, y, ...)NULL, quote(foo(1, x=2, extraArg=3, >> 4)), expand.dots=FALSE) >> foo(x = 2, y = 1, ... = list(extraArg = 3, 4)) >> >> Bill Dunlap >> TIBCO Software >> wdunlap tibco.com >> >> >>> -----Original Message----- >>> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] >>> On Behalf >>> Of Spencer Graves >>> Sent: Monday, April 07, 2014 3:05 PM >>> To: R list >>> Subject: [R] getting arg names in function calls? >>> >>> How can I convert "plot(0, 1)" into "plot(x=0, y=1)"? >>> >>> >>> More generally, how can I get argument names assigned to function >>> calls in "language" objects? >>> >>> >>> Example: >>> >>> >>> tstFn <- function()plot(0, 1) >>> bo <- body(tstFn) >>> >>> >>> tstFnxy <- function()plot(x=0, y=1) >>> boxy <- body(tstFnxy) >>> >>> >>> Is there a function that will modify "bo" to match "boxy"? >>> >>> >>> My current solution requires me to know the names of the >>> arguments for "plot" (in this example). I'd prefer a more general >>> solution. >>> >>> >>> Thanks, >>> Spencer >>> >>> >>> p.s. I'm trying to create an animation by repeatedly calling a function >>> that contains something like text(0, 1, "abc"). By computing on the >>> language object 'text(0, 1, "abc")', I can call text(0, 1, 'a') the >>> first time, text(0, 1, 'ab') the second, and text(0, 1, 'abc') the >>> third. The function will be more general if I can get the names of the >>> arguments as just described. >>> >>> ______________________________________________ >>> 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. > > > > -- > Spencer Graves, PE, PhD > President and Chief Technology Officer > Structure Inspection and Monitoring, Inc. > 751 Emerson Ct. > San José, CA 95126 > ph: 408-655-4567 > web: www.structuremonitoring.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. -- http://had.co.nz/ ______________________________________________ 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.
