The R Project SVN R

Rev

Rev 54339 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
54339 jmc 1 
mEditor <- setRefClass("matrixEditor",
2 
      fields = list( data = "matrix",
3 
        edits = "list"),
4 
      methods = list(
5 
     edit = function(i, j, value) {
6 
       ## the following string documents the edit method
7 
       'Replaces the range [i, j] of the
8 
        object by value.
9 
        '
10 
         backup <-
11 
             list(i, j, data[i,j])
12 
         data[i,j] <<- value
13 
         edits <<- c(edits, list(backup))
14 
         invisible(value)
15 
     },
16 
     undo = function() {
17 
       'Undoes the last edit() operation
18 
        and update the edits field accordingly.
19 
        '
20 
         prev <- edits
21 
         if(length(prev)) prev <- prev[[length(prev)]]
22 
         else stop("No more edits to undo")
23 
         edit(prev[[1]], prev[[2]], prev[[3]])
24 
         ## trim the edits list
25 
         length(edits) <<- length(edits) - 2
26 
         invisible(prev)
27 
     }
28 
     ))
29 
 
30 
xMat <- xEdited <- matrix(as.double(1:12),4,3)
31 
xEdited[[2,2]] <- 0
32 
xx <- mEditor$new(data = xMat)
33 
xx$edit(2, 2, 0)
34 
stopifnot(identical(xx$data, xEdited))
35 
xEdited[[1,3]] <- -1
36 
xx$edit(1,3, -1)
37 
stopifnot(identical(xx$data, xEdited))
38 
xx$undo()
39 
xEdited[[1,3]] <- xMat[[1,3]]
40 
stopifnot(identical(xx$data, xEdited))
41 
xx$undo()
42 
stopifnot(identical(xx$data, xMat))
55578 jmc 43 
 
44 
## the tracing method
45 
xx$trace(edit, quote(value <- 0))
46 
xx$edit(2,2, -1) # traced should assign 0
47 
stopifnot(identical(xx$data, xEdited))
48 
xx$untrace(edit)
49 
xx$edit(1, 3, -1) # now it should use -1
50 
xEdited[[1,3]] <- -1
51 
stopifnot(identical(xx$data, xEdited))