A drake-plan-like pipeline DSL

Simplify target specification in pipelines.

Usage

tar_plan(...)

Arguments

...

Named and unnamed targets. All named targets must follow the drake-plan-like target = command syntax, and all unnamed arguments must be explicit calls to create target definition objects, e.g. tar_target(), target factories like tar_render(), or similar.

Value

A list of tar_target() objects. See the "Target definition objects" section for background.

Details

Allows targets with just targets and commands to be written in the pipeline as target = command instead of tar_target(target, command). Also supports ordinary target definition objects if they are unnamed. tar_plan(x = 1, y = 2, tar_target(z, 3), tar_render(r, "r.Rmd")) is equivalent to:

  list(
    tar_target(x, 1),
    tar_target(y, 2),
    tar_target(z, 3),
    tar_render(r, "r.Rmd")
  )

Target definition objects

Most tarchetypes functions are target factories, which means they return target definition objects or lists of target definition objects. target definition objects represent skippable steps of the analysis pipeline as described at https://books.ropensci.org/targets/. Please read the walkthrough at https://books.ropensci.org/targets/walkthrough.html to understand the role of target definition objects in analysis pipelines.

For developers, https://wlandau.github.io/targetopia/contributing.html#target-factories explains target factories (functions like this one which generate targets) and the design specification at https://books.ropensci.org/targets-design/ details the structure and composition of target definition objects.

Examples

if (identical(Sys.getenv("TAR_LONG_EXAMPLES"), "true")) {
targets::tar_dir({ # tar_dir() runs code from a temporary directory.
targets::tar_script({
  library(tarchetypes)
  tar_plan(
    tarchetypes::tar_fst_tbl(data, data.frame(x = seq_len(26))),
    means = colMeans(data) # No need for tar_target() for simple cases.
  )
})
targets::tar_make()
})
}