On 14/10/2018 8:19 PM, Abs Spurdle wrote:
Kia OraLet's say we have: "myreplacementfunction<-" = function (..., value) { call = sys.call () print (as.list (call) ) 0 } Then we call: x = 0 myreplacementfunction (x, y, z) = 0 It will return: [[1]] `myreplacementfunction<-` [[2]] `*tmp*` [[3]] y [[4]] z $value <promise: 0x06fb6968> There's two problems here. Firstly, x has to be defined otherwise we get an error message. Secondly, the first argument is returned as *tmp*. Both are incorrect.
Both of these are documented (by example) in the R Language Definition manual, section 3.4.4:
"Assignment to subsets of a structure is a special case of a general mechanism for complex assignment:
x[3:5] <- 13:15 The result of this command is as if the following had been executed `*tmp*` <- x x <- "[<-"(`*tmp*`, 3:5, value=13:15) rm(`*tmp*`)" Duncan Murdoch
It should be possible to call the function without defining x. And it should return x rather than *tmp*. In other words, replacement function calls should be the same as other function calls. Although it gets y and z right. kind regards Abs ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
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