prefab

prefab provides an opinionated theme system for setting up R projects. A theme is a function that returns an ordered list of steps that deploy files, inject text, or run functions. Because themes are functions, they take parameters, compose with +, and ship in packages. Nothing touches the file system until you apply a theme with use_theme() or create_project().

Installation

install.packages(
  "prefab", 
  repos = c("https://economic.r-universe.dev", getOption("repos"))
)

Quick start

Create a new project with scaffolding and Claude Code config:

library(prefab)

create_project("~/projects/my-analysis", r_analysis() + claude_r_analysis())

Add a theme to an existing project:

use_theme(claude_r_analysis())

Built-in themes

Theme	Description
r_analysis()	main.R, README.md, .gitignore
r_targets()	_targets.R, packages.R, README.md, R/ dir, .gitignore
claude_r_analysis()	Claude Code settings and rules for analysis projects
claude_r_targets()	Claude Code settings and rules for targets projects

Composition

Themes compose with +. Steps execute left-to-right:

# Project structure + agent config in one call
theme <- r_targets() + claude_r_targets()

create_project("my-project", theme)

Custom themes

Build themes from steps using step_file(), step_text(), step_run(), and source helpers like from_dir():

from_shared <- from_dir("~/shared-config")

my_theme <- new_theme(
  from_shared("header.R", "R/header.R"),
  step_text(c("*.csv", "*.rds"), ".gitignore", strategy = "union"),
  step_run(fs::dir_create, "output", .label = "fs::dir_create")
)

# Combine with built-in themes
create_project("my-project", r_analysis() + my_theme)

Source helpers resolve file paths from a directory (from_dir()) or an installed R package (from_package()). Files with data = list(...) support {{var}} template interpolation via glue.

Merge strategies

Each step has a strategy that controls how it interacts with existing files:

Strategy	Behaviour
"overwrite"	Replace the file (default)
"skip"	Do nothing if the file exists
"union"	Merge lines, keeping unique entries
"append"	Add content to the end of the file
"merge_json"	Deep-merge JSON trees

Inspecting themes

Use theme_code() to print the R code that reproduces any theme. This is useful for understanding what a built-in theme does or as a starting point for customization:

theme_code(r_analysis())
#> new_theme(
#>   from_package("prefab")("r_analysis/main.R", "main.R", strategy = "skip"),
#>   from_package("prefab")("r_analysis/README.md", "README.md", strategy = "skip", data = list()),
#>   step_text(c(".Rproj.user", ".Rhistory", ".RData", ".DS_Store"), ".gitignore", strategy = "union")
#> )

Acknowledgments

This package draws heavily on ideas from the R packages:

• starter by Daniel D. Sjoberg
• usethis by Hadley Wickham, Jennifer Bryan, Malcolm Barrett, and Andy Teucher.

License

MIT