Set columns with a named list. do.call(":=", list())

[myoung3]

A request for this to work seen in the wild: https://stackoverflow.com/questions/66917673/set-multiple-columns-in-r-data-table-with-a-named-list-and

library(data.table)
dt <- data.table(a=0)
dt[, do.call(`:=`, list(b=1,c=2))]
#> Error in (function (...) : Check that is.data.table(DT) == TRUE. Otherwise, := and `:=`(...) are defined for use in j, once only and in particular ways. See help(":=").

^{Created on 2021-04-02 by the reprex package (v1.0.0)}

[myoung3]

also seen here: https://stackoverflow.com/questions/51861038/data-table-assigning-multiple-columns-generated-as-a-new-data-table-or-list-wi?rq=1

[myoung3]

closing since this is actually a duplicate of #1543.