Implement tar_load_globals()

NAMESPACE

@@ -278,6 +278,7 @@ export(tar_helper)
 export(tar_helper_raw)
 export(tar_invalidate)
 export(tar_load)
+export(tar_load_globals)
 export(tar_load_raw)
 export(tar_make)
 export(tar_make_clustermq)

R/tar_load_globals.R

@@ -0,0 +1,51 @@
+#' @title Load globals for debugging, testing, and prototyping
+#' @export
+#' @family debug
+#' @description Load user-defined functions, global objects, and
+#'   settings defined in the target script file (default: `_targets.R`).
+#'   This function is for debugging, testing, and prototyping only.
+#'   It is not recommended for use inside a serious pipeline
+#'   or to report the results of a serious pipeline.
+#' @details This function first sources the target script file
+#'   (default: `_targets.R`)
+#'   to loads all user-defined functions, global objects, and settings
+#'   into the current R process. Then, it loads all the packages defined
+#'   in `tar_option_get("packages")` (default: `(.packages())`)
+#'   using `library()` with `lib.loc` defined in `tar_option_get("library")`
+#'   (default: `NULL`).
+#' @return `NULL` (invisibly).
+#' @inheritParams tar_config_set
+#' @param envir Environment to source the target script (default: `_targets.R`).
+#'   Defaults to the calling environment.
+#' @examples
+#' if (identical(Sys.getenv("TAR_LONG_EXAMPLES"), "true")) {
+#' tar_dir({ # tar_dir() runs code from a temporary directory.
+#' tar_script({
+#'   tar_option_set(packages = "callr")
+#'   analyze_data <- function(data) {
+#'     summary(data)
+#'   }
+#'   list(
+#'     tar_target(x, 1 + 1),
+#'     tar_target(y, 1 + 1)
+#'   )
+#' }, ask = FALSE)
+#' tar_load_globals()
+#' print(analyze_data)
+#' print("callr" %in% (.packages()))
+#' })
+#' }
+tar_load_globals <- function(
+  envir = parent.frame(),
+  script = targets::tar_config_get("script")
+) {
+  force(envir)
+  eval(parse(text = readLines(script)), envir = envir)
+  map(
+    x = tar_option_get("packages"),
+    f = library,
+    character.only = TRUE,
+    lib.loc = tar_option_get("library")
+  )
+  invisible()
+}

R/tar_workspace.R

@@ -72,7 +72,7 @@ tar_workspace <- function(
     build_load_packages(command$packages, command$library)
   }
   if (source) {
-    source(script, local = envir)
+    eval(parse(text = readLines(script)), envir = envir)
   }
   set.seed(workspace$target$command$seed)
   invisible()

_pkgdown.yml

@@ -51,6 +51,7 @@ reference:
   - '`tar_make_future`'
 - title: Debug
   contents:
+  - '`tar_load_globals`'
   - '`tar_traceback`'
   - '`tar_workspace`'
   - '`tar_workspaces`'

tests/testthat/test-tar_load_globals.R

@@ -0,0 +1,16 @@
+tar_test("tar_load_globals", {
+  tar_script({
+    tar_option_set(packages = "callr")
+    analyze_data <- function(data) {
+      summary(data)
+    }
+    list(
+      tar_target(x, 1 + 1),
+      tar_target(y, 1 + 1)
+    )
+  }, ask = FALSE)
+  envir <- new.env(parent = globalenv())
+  tar_load_globals(envir = envir)
+  expect_true(is.function(envir$analyze_data))
+  expect_true("callr" %in% (.packages()))
+})