batchExport() and objects with non-standard names

[HenrikBengtsson]

Problem

It is not possible to export objects with non-standard names, e.g.

> batchExport(reg, li=list("%>%"=NA))
Error in batchExport(reg, li = list(`%>%` = NA)) :
  Assertion on 'li' failed: Vector must be named according to R's variable naming rules

Troubleshooting

This due to the following assertion:

assertList(li, names = "strict")

Suggestion

I propose to make names="strict" and argument of batchExport(), e.g.

batchExport <- function (reg, ..., li = list(), overwrite = FALSE, names = "strict")
{
    checkRegistry(reg)
    ddd = list(...)
    assertList(li, names = names)
    assertList(ddd, names = names)
...

so that it's possible to do:

> batchExport(reg, li=list("%>%"=NA), names = "any")

The argument name names might not be the most informative though to a user of batchExport().

[HenrikBengtsson]

Just discovered another use case:

globals <- list("names<-"=NA)
batchExport(reg, li=globals)
Error in batchExport(reg, li = list(`%>%` = NA)) :
  Assertion on 'li' failed: Vector must be named according to R's variable naming rules

assertList(li, names = "strict")

[HenrikBengtsson]

So, assertList() is not the main issue, but rather the restriction on put() on fail objects that is called by batchExport():

    f = fail(...)
...
    f$put(li = li)
    f$put(li = ddd)

The restriction on "keys" for fail objects is basically [a-zA-Z0-9._-]+, cf. help("fail", package="fail").

In other words, it looks like the fail package needs to be update to support other type of variable names.

An alternative is to have batchExport() / loadExport() / batchUnexport() to encode/decode variable names to filename compatible strings. Can key <- utils::URLencode(var, reserved = TRUE) and var <- utils::URLdecode(key) be used for this?

EDIT: URL decode/encode functions are in the utils package (not tools).