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Suppress dependency detection. [Stable]

Source: R/drake_plan_helpers.R
no_deps.Rd

Tell drake to not search for dependencies in a chunk of code.

Usage

no_deps(x = NULL)

Arguments

x

Code for which dependency detection is suppressed.

Value

The argument.

Details

no_deps() is similar to ignore(), but it still lets drake track meaningful changes to the code itself.

Keywords

drake_plan() understands special keyword functions for your commands. With the exception of target(), each one is a proper function with its own help file.

  • target(): give the target more than just a command. Using target(), you can apply a transformation (examples: https://books.ropensci.org/drake/plans.html#large-plans), # nolint supply a trigger (https://books.ropensci.org/drake/triggers.html), # nolint or set any number of custom columns.

  • file_in(): declare an input file dependency.

  • file_out(): declare an output file to be produced when the target is built.

  • knitr_in(): declare a knitr file dependency such as an R Markdown (*.Rmd) or R LaTeX (*.Rnw) file.

  • ignore(): force drake to entirely ignore a piece of code: do not track it for changes and do not analyze it for dependencies.

  • no_deps(): tell drake to not track the dependencies of a piece of code. drake still tracks the code itself for changes.

  • id_chr(): Get the name of the current target.

  • drake_envir(): get the environment where drake builds targets. Intended for advanced custom memory management.

See also

file_in(), file_out(), knitr_in(), no_deps()

Examples

if (FALSE) {
isolate_example("Contain side effects", {
# Normally, `drake` reacts to changes in dependencies.
x <- 4
make(plan = drake_plan(y = sqrt(x)))
x <- 5
make(plan = drake_plan(y = sqrt(x)))
make(plan = drake_plan(y = sqrt(4) + x))
# But not with no_deps().
make(plan = drake_plan(y = sqrt(4) + no_deps(x))) # Builds y.
x <- 6
make(plan = drake_plan(y = sqrt(4) + no_deps(x))) # Skips y.
# However, `drake` *does* react to changes
# to the *literal code* inside `no_deps()`.
make(plan = drake_plan(y = sqrt(4) + ignore(x + 1))) # Builds y.

# Like ignore(), no_deps() works with functions and multiline code chunks.
z <- 1
f <- function(x) {
  no_deps({
    x <- z + 1
    x <- x + 2
  })
  x
}
make(plan = drake_plan(y = f(2)))
readd(y)
z <- 2 # Changed dependency is not tracked.
make(plan = drake_plan(y = f(2)))
readd(y)
})
}