Can't add nodeset via xml_add_sibling()

[krlmlr]

Issue Description and Expected Result

xml_add_sibling() throws an error when passing a nodeset as .value argument. I'd expect all nodes to be copied/moved.

Reproducible Example

library(xml2)

xml <- read_xml("<parent><child1/><child2/><child3/></parent>")
children <- xml_children(xml)
children
#> {xml_nodeset (3)}
#> [1] <child1/>
#> [2] <child2/>
#> [3] <child3/>
# Can't add nodeset
xml_add_sibling(children[[1]], children)
#> Error: `.value` must be a character
xml
#> {xml_document}
#> <parent>
#> [1] <child1/>
#> [2] <child2/>
#> [3] <child3/>
# Can add individual nodes
xml_add_sibling(children[[1]], children[[2]])
xml
#> {xml_document}
#> <parent>
#> [1] <child1/>
#> [2] <child2/>
#> [3] <child2/>
#> [4] <child3/>

Session info

devtools::session_info()
#> Session info -------------------------------------------------------------
#>  setting  value                       
#>  version  R version 3.3.2 (2016-10-31)
#>  system   x86_64, linux-gnu           
#>  ui       X11                         
#>  language en_US:en                    
#>  collate  en_US.UTF-8                 
#>  tz       Europe/Busingen             
#>  date     2017-03-01
#> Packages -----------------------------------------------------------------
#>  package   * version     date       source                          
#>  backports   1.0.5       2017-01-18 CRAN (R 3.3.2)                  
#>  devtools    1.12.0.9000 2017-01-25 local                           
#>  digest      0.6.12      2017-01-27 cran (@0.6.12)                  
#>  evaluate    0.10        2016-10-11 cran (@0.10)                    
#>  htmltools   0.3.5       2016-03-21 CRAN (R 3.3.0)                  
#>  knitr       1.15.1      2016-11-22 CRAN (R 3.3.2)                  
#>  magrittr    1.5         2016-05-26 local                           
#>  memoise     1.0.0       2016-01-29 CRAN (R 3.3.0)                  
#>  pkgbuild    0.0.0.9000  2016-12-06 local                           
#>  pkgload     0.0.0.9000  2017-01-25 local                           
#>  Rcpp        0.12.9      2017-01-14 CRAN (R 3.3.2)                  
#>  rmarkdown   1.3         2016-12-21 CRAN (R 3.3.2)                  
#>  rprojroot   1.2         2017-01-25 local (krlmlr/rprojroot@6d1069c)
#>  stringi     1.1.2       2016-10-01 cran (@1.1.2)                   
#>  stringr     1.1.0.9000  2017-01-25 local                           
#>  withr       1.0.2       2017-02-24 local                           
#>  xml2      * 1.1.1       2017-01-24 CRAN (R 3.3.2)                  
#>  yaml        2.1.14      2016-11-12 CRAN (R 3.3.2)

[jordansread]

same with xml_add_child, where the docs look like .value can be a nodeset, but it has the same error as above.

@krlmlr do you have a current workaround? I am running into similar trouble adding a lot of nodes (~30K) at once as looping per child bogs down the more I add.

[krlmlr]

Unfortunately not.

[jordansread]

Thanks

[jimhester]

All of the modification functions have nodeset methods for the first argument, not the second. So you can do xml_add_sibling(children, children[[1]]), but not the reverse. If you want to do what you are suggesting just use a loop.

for (child in children) {
  xml_add_sibling(children[[1]], child)
}

[krlmlr]

Is this a limitation of the libxml2 API, or could we perhaps support these use cases? I needed this to move a chunk of a HTML document to another place.

[jordansread]

Part of the confusion on this for me is that the doc says

xml2/man/xml_replace.Rd

Line 26 in 1856377

\item{.value}{node or nodeset to insert.}

should it just be node to insert. ?