search for: evallistkeepmissing

...at I wrote about on my blog at radfordneal.wordpress.com (see the posts on "Speeding up parentheses..." and "Two surprising things...". I discovered that the strange speed advantage of curly brackets over parentheses is partially explained by an inefficiency in the evalList and evalListKeepMissing procedures in eval.c, in directory src/main, which are on the critical path for many operations. These procedures unnecessarily allocate an extra CONS node. I rewrote them to avoid this, which seems to speed up a typical program by about 5% (assuming it doesn't spend most of its time in thing...

R> myfun <- function(x, ...) {x[...] <- 0; x} R> myfun(3) Error in myfun(3) : SubAssignArgs: invalid number of arguments It fails because no ... was passed. The workaround (and desired behavior) is: R> myfun <- function(x, ...) {if (missing(...)) x[] <- 0 else x[...] <- 0; x} R> myfun(3) [1] 0 Deja vu? This is the one piece of my PR#1110 (Oct 3, 2001) that I