tar_definition: For developers only: get the definition of the current...

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

For developers only: get the definition of the current target.

Description

For developers only: get the full definition of the target currently running. This target definition is the same kind of object produced by tar_target().

Usage

tar_definition(
  default = targets::tar_target_raw("target_name", quote(identity()))
)

Arguments

default

Environment, value to return if tar_definition() is called on its own outside a targets pipeline. Having a default lets users run things without tar_make(), which helps peel back layers of code and troubleshoot bugs.

Details

Most users should not use tar_definition() because accidental modifications could break the pipeline. tar_definition() only exists in order to support third-party interface packages, and even then the returned target definition is not modified..

Value

If called from a running target, tar_definition() returns the target object of the currently running target. See the "Target objects" section for details.

Target objects

Functions like tar_target() produce target objects, special objects with specialized sets of S3 classes. Target 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 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 objects.

See Also

Other utilities: tar_active(), tar_backoff(), tar_call(), tar_cancel(), 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_source(), tar_store()

Examples

class(tar_definition())
tar_definition()$settings$name
if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) { # for CRAN
tar_dir({ # tar_dir() runs code from a temp dir for CRAN.
tar_script(
  tar_target(x, tar_definition()$settings$memory, memory = "transient")
)
tar_make(x)
tar_read(x)
})
}

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