tar_source: Run R scripts.

In targets: Dynamic Function-Oriented 'Make'-Like Declarative Pipelines

Run R scripts.

Description

Run all the R scripts in a directory in the environment specified.

Usage

tar_source(
  files = "R",
  envir = targets::tar_option_get("envir"),
  change_directory = FALSE
)

Arguments

files	Character vector of file and directory paths to look for R scripts to run. Paths must either be absolute paths or must be relative to the current working directory just before the function call.
envir	Environment to run the scripts. Defaults to tar_option_get("envir"), the environment of the pipeline.
change_directory	Logical, whether to temporarily change the working directory to the directory of each R script before running it.

Details

tar_source() is a convenient way to load R scripts in ⁠_targets.R⁠ to make custom functions available to the pipeline. tar_source() recursively looks for files ending in .R or .r, and it runs each with eval(parse(text = readLines(script_file, warn = FALSE)), envir).

Value

NULL (invisibly)

Storage access

Several functions like tar_make(), tar_read(), tar_load(), tar_meta(), and tar_progress() read or modify the local data store of the pipeline. The local data store is in flux while a pipeline is running, and depending on how distributed computing or cloud computing is set up, not all targets can even reach it. So please do not call these functions from inside a target as part of a running pipeline. The only exception is literate programming target factories in the tarchetypes package such as tar_render() and tar_quarto().

See Also

Other utilities: tar_active(), tar_backoff(), tar_call(), tar_cancel(), tar_definition(), tar_described_as(), tar_envir(), tar_format_get(), tar_group(), tar_name(), tar_path(), tar_path_script(), tar_path_script_support(), tar_path_store(), tar_path_target(), tar_store()

Examples

if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) { # for CRAN
tar_dir({ # tar_dir() runs code from a temp dir for CRAN.
# Running in tar_dir(), these files are written in tempdir().
dir.create("R")
writeLines("f <- function(x) x + 1", file.path("R", "functions.R"))
tar_script({
  tar_source()
  list(tar_target(x, f(1)))
})
tar_make()
tar_read(x) # 2
})
}

targets documentation built on Oct. 3, 2024, 1:11 a.m.