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rlang is a collection of frameworks and APIs for programming with R.

Two comprehensive frameworks are implemented in rlang.

• tidy eval, a programmabledata-masking framework used in tidyverse packages like dplyr and ggplot2. As a user, you will encounter the embracing operator{{ and name injection with theglue operators"{" and"{{".

• rlang errors, a set of tools to signal and display errors. This includes backtrace capture withglobal_entrace() and backtrace display withlast_error() andlast_warnings(). Useabort() to create errors with bullet lists, structured metadata, and error chaining support.

  The display of error messages is optimised for bullet lists and chained errors and optionally integrates with the cli package (seelocal_use_cli()).

A set of tools help you check, validate, and preprocess arguments.

• Checking function arguments, e.g.arg_match(),check_required(), andcheck_exclusive().

• Checking dots, e.g.check_dots_used() andcheck_dots_empty().

• Collectingdynamic dots, e.g.list2(). These dots support splicing with!!! and name injection with theglue operators"{" and"{{".

rlang provides various interfaces for working with R and R objects.

• The R session, e.g.check_installed(),on_load(), andon_package_load().

• Environments, e.g.env(),env_has(),env_get(),env_bind(),env_unbind(),env_print(), andlocal_bindings().

• Evaluation, e.g.inject() andeval_bare().

• Calls and symbols, e.g.call2(),is_call(),is_call_simple(),data_sym(), anddata_syms().

• Functions, e.g.new_function() andas_function(). The latter supports the purrr-style formula notation for lambda functions.

Install the released version of rlang from CRAN:

install.packages("rlang")

Or install the development version from GitHub with:

# install.packages("pak")pak::pkg_install("r-lib/rlang")

Please note that the rlang project is released with aContributor Code of Conduct. By contributing to this project, you agree to abide by its terms.