Skip to contents

Create a Nix expression running an R function

Source: R/derivs.R
rxp_r.Rd

Create a Nix expression running an R function

Usage

rxp_r(
  name,
  expr,
  additional_files = "",
  nix_env = "default.nix",
  serialize_function = NULL,
  unserialize_function = NULL,
  env_var = NULL
)

Arguments

name

Symbol, name of the derivation.

expr

R code to generate the expression.

additional_files

Character vector, additional files to include. Custom functions must go into a script called "functions.R", and additional files that need to be accessible during the build process can be named anything.

nix_env

Character, path to the Nix environment file, default is "default.nix".

serialize_function

Function, defaults to NULL. A function used to serialize objects for transfer between derivations. It must accept two arguments: the object to serialize (first), and the target file path (second). If your function has a different signature, wrap it to match this interface. By default, saveRDS() is used, but this may yield unexpected results, especially for complex objects like machine learning models. For instance, for {keras} models, use keras::save_model_hdf5() to capture the full model (architecture, weights, training config, optimizer state, etc.).

unserialize_function

Function, defaults to NULL. A function used to unserialize objects transferred between derivations. By default, readRDS() is used, but this may produce unexpected results with complex objects like machine learning models. For example, if the parent derivation used keras::save_model_hdf5() to serialize a model, this derivation should use keras::load_model_hdf5() to load it correctly.

env_var

Character vector, defaults to NULL. A named vector of environment variables to set before running the R script, e.g., c("CMDSTAN" = "${defaultPkgs.cmdstan}/opt/cmdstan)". Each entry will be added as an export statement in the build phase.

Value

An object of class derivation which inherits from lists.

Details

At a basic level, rxp_r(mtcars_am, filter(mtcars, am == 1)) is equivalent to mtcars_am <- filter(mtcars, am == 1). rxp_r() generates the required Nix boilerplate to output a so-called "derivation" in Nix jargon. A Nix derivation is a recipe that defines how to create an output (in this case mtcars_am) including its dependencies, build steps, and output paths.

See also

Other derivations: rxp_jl(), rxp_py(), rxp_py_file(), rxp_qmd(), rxp_r_file(), rxp_rmd()

Examples

if (FALSE) { # \dontrun{
  # Basic usage
  rxp_r(name = filtered_mtcars, expr = filter(mtcars, am == 1))

  # Serialize object using qs
  rxp_r(
   name = filtered_mtcars,
   expr = filter(mtcars, am == 1),
   serialize_function = qs::qsave
  )
  # Unerialize using qs::qread in the next derivation
  rxp_r(
   name = mtcars_mpg,
   expr = select(filtered_mtcars, mpg),
   unserialize_function = qs::qread
  )
} # }