Read a target and stash it in an environment

Reads a target with targets::tar_read() and, in addition to returning it, assigns a copy into envir under a fixed scratch name (.target by default). This lets you keep a handle to the value for interactive exploration without re-running the read. It is the engine behind the rstudio_addin_tar_read_stash() addin.

Usage

tar_read_stash(
  name,
  stash_name = ".target",
  print_value = TRUE,
  envir = globalenv(),
  store = targets::tar_config_get("store"),
  ...
)

Arguments

name

Symbol or string, the target to read. NSE-friendly, matching targets::tar_read().

stash_name

String, the variable name to assign the value to in envir. Defaults to ".target", a leading-dot scratch slot. If it already exists in envir it is silently overwritten.

print_value

Logical. If TRUE (default), the value is printed after assignment so the addin behaves like the stock tar_read addin.

envir

Environment to stash the value into. Defaults to globalenv().

store

Character, the targets data store. Passed through to targets::tar_read_raw().

...

Additional arguments passed to targets::tar_read_raw() (e.g. branches).

Value

The target value, invisibly.

Details

A resolved character target name is passed to targets::tar_read_raw() rather than targets::tar_read(), because the latter uses non-standard evaluation and would otherwise look up a target named after the variable rather than its value.

When called from a non-interactive context (a script or pipeline), a warning is emitted but the value is still stashed.

Examples

if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) {
targets::tar_dir({
  targets::tar_script({
    library(targets)
    list(
      targets::tar_target(x, 1 + 1)
    )
  })
  targets::tar_make()
  tar_read_stash(x)
  .target
})
}