# rlang

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

## Frameworks

Two comprehensive frameworks are implemented in rlang.

- **tidy eval**, a programmable
  [data-masking](https://rlang.r-lib.org/reference/topic-data-mask.html)
  framework used in tidyverse packages like dplyr and ggplot2. As a
  user, you will encounter the embracing operator
  [`{{`](https://rlang.r-lib.org/reference/embrace-operator.html) and
  name injection with the [glue](https://glue.tidyverse.org/) operators
  [`"{"`](https://rlang.r-lib.org/reference/glue-operators.html) and
  [`"{{"`](https://rlang.r-lib.org/reference/glue-operators.html).

- **rlang errors**, a set of tools to signal and display errors. This
  includes backtrace capture with
  [`global_entrace()`](https://rlang.r-lib.org/reference/global_entrace.md)
  and backtrace display with
  [`last_error()`](https://rlang.r-lib.org/reference/last_error.md) and
  [`last_warnings()`](https://rlang.r-lib.org/reference/last_warnings.md).
  Use [`abort()`](https://rlang.r-lib.org/reference/abort.md) 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 (see
  [`local_use_cli()`](https://rlang.r-lib.org/reference/local_use_cli.md)).

## Argument intake

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

- Checking function arguments,
  e.g. [`arg_match()`](https://rlang.r-lib.org/reference/arg_match.md),
  [`check_required()`](https://rlang.r-lib.org/reference/check_required.md),
  and
  [`check_exclusive()`](https://rlang.r-lib.org/reference/check_exclusive.md).

- Checking dots,
  e.g. [`check_dots_used()`](https://rlang.r-lib.org/reference/check_dots_used.md)
  and
  [`check_dots_empty()`](https://rlang.r-lib.org/reference/check_dots_empty.md).

- Collecting [dynamic
  dots](https://rlang.r-lib.org/reference/dyn-dots.html),
  e.g. [`list2()`](https://rlang.r-lib.org/reference/list2.md). These
  dots support splicing with
  [`!!!`](https://rlang.r-lib.org/reference/splice-operator.html) and
  name injection with the [glue](https://glue.tidyverse.org/) operators
  [`"{"`](https://rlang.r-lib.org/reference/glue-operators.html) and
  [`"{{"`](https://rlang.r-lib.org/reference/glue-operators.html).

## Programming interfaces

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

- The R session,
  e.g. [`check_installed()`](https://rlang.r-lib.org/reference/is_installed.md),
  [`on_load()`](https://rlang.r-lib.org/reference/on_load.md), and
  [`on_package_load()`](https://rlang.r-lib.org/reference/on_load.md).

- Environments,
  e.g. [`env()`](https://rlang.r-lib.org/reference/env.md),
  [`env_has()`](https://rlang.r-lib.org/reference/env_has.md),
  [`env_get()`](https://rlang.r-lib.org/reference/env_get.md),
  [`env_bind()`](https://rlang.r-lib.org/reference/env_bind.md),
  [`env_unbind()`](https://rlang.r-lib.org/reference/env_unbind.md),
  [`env_print()`](https://rlang.r-lib.org/reference/env_print.md), and
  [`local_bindings()`](https://rlang.r-lib.org/reference/local_bindings.md).

- Evaluation,
  e.g. [`inject()`](https://rlang.r-lib.org/reference/inject.md) and
  [`eval_bare()`](https://rlang.r-lib.org/reference/eval_bare.md).

- Calls and symbols,
  e.g. [`call2()`](https://rlang.r-lib.org/reference/call2.md),
  [`is_call()`](https://rlang.r-lib.org/reference/is_call.md),
  [`is_call_simple()`](https://rlang.r-lib.org/reference/call_name.md),
  [`data_sym()`](https://rlang.r-lib.org/reference/sym.md), and
  [`data_syms()`](https://rlang.r-lib.org/reference/sym.md).

- Functions,
  e.g. [`new_function()`](https://rlang.r-lib.org/reference/new_function.md)
  and
  [`as_function()`](https://rlang.r-lib.org/reference/as_function.md).
  The latter supports the purrr-style formula notation for lambda
  functions.

## Installation

Install the released version of rlang from CRAN:

``` r
install.packages("rlang")
```

Or install the development version from GitHub with:

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

## Code of Conduct

Please note that the rlang project is released with a [Contributor Code
of Conduct](https://rlang.r-lib.org/CODE_OF_CONDUCT.html). By
contributing to this project, you agree to abide by its terms.

# Package index

## Tidy evaluation

The programmable data-masking framework developed for the tidyverse.

### Tools

- [`embrace-operator`](https://rlang.r-lib.org/reference/embrace-operator.md)
  [`curly-curly`](https://rlang.r-lib.org/reference/embrace-operator.md)
  :

  Embrace operator `{{`

- [`glue-operators`](https://rlang.r-lib.org/reference/glue-operators.md)
  :

  Name injection with `"{"` and `"{{"`

- [`dot-data`](https://rlang.r-lib.org/reference/dot-data.md)
  [`.data`](https://rlang.r-lib.org/reference/dot-data.md)
  [`tidyeval-data`](https://rlang.r-lib.org/reference/dot-data.md)
  [`.env`](https://rlang.r-lib.org/reference/dot-data.md) :

  `.data` and `.env` pronouns

### Metaprogramming tools

- [`injection-operator`](https://rlang.r-lib.org/reference/injection-operator.md)
  [`bang-bang`](https://rlang.r-lib.org/reference/injection-operator.md)
  [`!!`](https://rlang.r-lib.org/reference/injection-operator.md) :

  Injection operator `!!`

- [`splice-operator`](https://rlang.r-lib.org/reference/splice-operator.md)
  [`!!!`](https://rlang.r-lib.org/reference/splice-operator.md) :

  Splice operator `!!!`

- [`qq_show`](https://rlang.r-lib.org/reference/qq_show.md) : Show
  injected expression

- [`englue()`](https://rlang.r-lib.org/reference/englue.md) : Defuse
  function arguments with glue

- [`expr`](https://rlang.r-lib.org/reference/expr.md) : Defuse an R
  expression

- [`enquo()`](https://rlang.r-lib.org/reference/enquo.md)
  [`enquos()`](https://rlang.r-lib.org/reference/enquo.md) : Defuse
  function arguments

- [`sym()`](https://rlang.r-lib.org/reference/sym.md)
  [`syms()`](https://rlang.r-lib.org/reference/sym.md)
  [`data_sym()`](https://rlang.r-lib.org/reference/sym.md)
  [`data_syms()`](https://rlang.r-lib.org/reference/sym.md) : Create a
  symbol or list of symbols

- [`as_label()`](https://rlang.r-lib.org/reference/as_label.md) : Create
  a default name for an R object

- [`as_name()`](https://rlang.r-lib.org/reference/as_name.md) : Extract
  names from symbols

### Advanced tools

- [`enexpr()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  [`exprs()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  [`enexprs()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  [`ensym()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  [`ensyms()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  [`quo()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  [`quos()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  [`enquo0()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  [`enquos0()`](https://rlang.r-lib.org/reference/defusing-advanced.md)
  : Advanced defusal operators
- [`eval_tidy()`](https://rlang.r-lib.org/reference/eval_tidy.md) :
  Evaluate an expression with quosures and pronoun support
- [`as_data_mask()`](https://rlang.r-lib.org/reference/as_data_mask.md)
  [`as_data_pronoun()`](https://rlang.r-lib.org/reference/as_data_mask.md)
  [`new_data_mask()`](https://rlang.r-lib.org/reference/as_data_mask.md)
  : Create a data mask

## Function arguments

### Check arguments

- [`arg_match()`](https://rlang.r-lib.org/reference/arg_match.md)
  [`arg_match0()`](https://rlang.r-lib.org/reference/arg_match.md) :
  Match an argument to a character vector
- [`check_exclusive()`](https://rlang.r-lib.org/reference/check_exclusive.md)
  : Check that arguments are mutually exclusive
- [`check_required()`](https://rlang.r-lib.org/reference/check_required.md)
  : Check that argument is supplied
- [`missing_arg()`](https://rlang.r-lib.org/reference/missing_arg.md)
  [`is_missing()`](https://rlang.r-lib.org/reference/missing_arg.md)
  [`maybe_missing()`](https://rlang.r-lib.org/reference/missing_arg.md)
  : Generate or handle a missing argument

### Check dots

- [`check_dots_empty()`](https://rlang.r-lib.org/reference/check_dots_empty.md)
  : Check that dots are empty
- [`check_dots_used()`](https://rlang.r-lib.org/reference/check_dots_used.md)
  : Check that all dots have been used
- [`check_dots_unnamed()`](https://rlang.r-lib.org/reference/check_dots_unnamed.md)
  : Check that all dots are unnamed

### Collect dynamic dots

Collect arguments contained in `...` with `!!!` and name-injection
support.

- [`dyn-dots`](https://rlang.r-lib.org/reference/dyn-dots.md)
  [`tidy-dots`](https://rlang.r-lib.org/reference/dyn-dots.md)
  [`doc_dots_dynamic`](https://rlang.r-lib.org/reference/dyn-dots.md)
  [`:=`](https://rlang.r-lib.org/reference/dyn-dots.md) : Dynamic dots
  features
- [`list2()`](https://rlang.r-lib.org/reference/list2.md)
  [`dots_list()`](https://rlang.r-lib.org/reference/list2.md) : Collect
  dynamic dots in a list
- [`pairlist2()`](https://rlang.r-lib.org/reference/pairlist2.md) :
  Collect dynamic dots in a pairlist
- [`splice()`](https://rlang.r-lib.org/reference/splice.md)
  [`is_spliced()`](https://rlang.r-lib.org/reference/splice.md)
  [`is_spliced_bare()`](https://rlang.r-lib.org/reference/splice.md) :
  Splice values at dots collection time

## Error handling

### Signal errors and other conditions

- [`abort()`](https://rlang.r-lib.org/reference/abort.md)
  [`warn()`](https://rlang.r-lib.org/reference/abort.md)
  [`inform()`](https://rlang.r-lib.org/reference/abort.md)
  [`signal()`](https://rlang.r-lib.org/reference/abort.md)
  [`reset_warning_verbosity()`](https://rlang.r-lib.org/reference/abort.md)
  [`reset_message_verbosity()`](https://rlang.r-lib.org/reference/abort.md)
  : Signal an error, warning, or message
- [`cnd_signal()`](https://rlang.r-lib.org/reference/cnd_signal.md) :
  Signal a condition object
- [`local_use_cli()`](https://rlang.r-lib.org/reference/local_use_cli.md)
  **\[experimental\]** : Use cli to format error messages

### Handle errors

- [`global_handle()`](https://rlang.r-lib.org/reference/global_handle.md)
  : Register default global handlers
- [`global_entrace()`](https://rlang.r-lib.org/reference/global_entrace.md)
  : Entrace unexpected errors
- [`global_prompt_install()`](https://rlang.r-lib.org/reference/global_prompt_install.md)
  : Prompt user to install missing packages
- [`try_fetch()`](https://rlang.r-lib.org/reference/try_fetch.md)
  **\[experimental\]** : Try an expression with condition handlers
- [`caller_arg`](https://rlang.r-lib.org/reference/caller_arg.md) : Find
  the caller argument for error messages
- [`local_error_call()`](https://rlang.r-lib.org/reference/local_error_call.md)
  : Set local error call in an execution environment
- [`args_error_context`](https://rlang.r-lib.org/reference/args_error_context.md)
  : Documentation anchor for error arguments
- [`catch_cnd()`](https://rlang.r-lib.org/reference/catch_cnd.md) :
  Catch a condition

### Backtraces

- [`last_error()`](https://rlang.r-lib.org/reference/last_error.md)
  [`last_trace()`](https://rlang.r-lib.org/reference/last_error.md) :

  Last [`abort()`](https://rlang.r-lib.org/reference/abort.md) error

- [`last_warnings()`](https://rlang.r-lib.org/reference/last_warnings.md)
  [`last_messages()`](https://rlang.r-lib.org/reference/last_warnings.md)
  : Display last messages and warnings

- [`global_entrace()`](https://rlang.r-lib.org/reference/global_entrace.md)
  : Entrace unexpected errors

- [`rlang_backtrace_on_error`](https://rlang.r-lib.org/reference/rlang_backtrace_on_error.md)
  [`add_backtrace`](https://rlang.r-lib.org/reference/rlang_backtrace_on_error.md)
  [`rlang_backtrace_on_error_report`](https://rlang.r-lib.org/reference/rlang_backtrace_on_error.md)
  [`rlang_backtrace_on_warning_report`](https://rlang.r-lib.org/reference/rlang_backtrace_on_error.md)
  : Display backtrace on error

- [`trace_back()`](https://rlang.r-lib.org/reference/trace_back.md)
  [`trace_length()`](https://rlang.r-lib.org/reference/trace_back.md) :
  Capture a backtrace

### Conditions

- [`rlang_error`](https://rlang.r-lib.org/reference/rlang_error.md)
  **\[experimental\]** :

  Errors of class `rlang_error`

- [`cnd_message()`](https://rlang.r-lib.org/reference/cnd_message.md)
  [`cnd_header()`](https://rlang.r-lib.org/reference/cnd_message.md)
  [`cnd_body()`](https://rlang.r-lib.org/reference/cnd_message.md)
  [`cnd_footer()`](https://rlang.r-lib.org/reference/cnd_message.md) :
  Build an error message from parts

- [`format_error_bullets()`](https://rlang.r-lib.org/reference/format_error_bullets.md)
  : Format bullets for error messages

- [`cnd_inherits()`](https://rlang.r-lib.org/reference/cnd_inherits.md)
  : Does a condition or its ancestors inherit from a class?

## Session

### State

- [`is_installed()`](https://rlang.r-lib.org/reference/is_installed.md)
  [`check_installed()`](https://rlang.r-lib.org/reference/is_installed.md)
  : Are packages installed in any of the libraries?
- [`is_interactive()`](https://rlang.r-lib.org/reference/is_interactive.md)
  [`local_interactive()`](https://rlang.r-lib.org/reference/is_interactive.md)
  [`with_interactive()`](https://rlang.r-lib.org/reference/is_interactive.md)
  : Is R running interactively?
- [`local_options()`](https://rlang.r-lib.org/reference/local_options.md)
  [`with_options()`](https://rlang.r-lib.org/reference/local_options.md)
  [`push_options()`](https://rlang.r-lib.org/reference/local_options.md)
  [`peek_options()`](https://rlang.r-lib.org/reference/local_options.md)
  [`peek_option()`](https://rlang.r-lib.org/reference/local_options.md)
  : Change global options
- [`on_load()`](https://rlang.r-lib.org/reference/on_load.md)
  [`run_on_load()`](https://rlang.r-lib.org/reference/on_load.md)
  [`on_package_load()`](https://rlang.r-lib.org/reference/on_load.md) :
  Run expressions on load
- [`faq-options`](https://rlang.r-lib.org/reference/faq-options.md) :
  Global options for rlang

### Search path and namespaces

- [`search_envs()`](https://rlang.r-lib.org/reference/search_envs.md)
  [`search_env()`](https://rlang.r-lib.org/reference/search_envs.md)
  [`pkg_env()`](https://rlang.r-lib.org/reference/search_envs.md)
  [`pkg_env_name()`](https://rlang.r-lib.org/reference/search_envs.md)
  [`is_attached()`](https://rlang.r-lib.org/reference/search_envs.md)
  [`base_env()`](https://rlang.r-lib.org/reference/search_envs.md)
  [`global_env()`](https://rlang.r-lib.org/reference/search_envs.md) :
  Search path environments
- [`empty_env()`](https://rlang.r-lib.org/reference/empty_env.md) : Get
  the empty environment
- [`is_namespace()`](https://rlang.r-lib.org/reference/is_namespace.md)
  : Is an object a namespace environment?
- [`ns_env()`](https://rlang.r-lib.org/reference/ns_env.md)
  [`ns_imports_env()`](https://rlang.r-lib.org/reference/ns_env.md)
  [`ns_env_name()`](https://rlang.r-lib.org/reference/ns_env.md) : Get
  the namespace of a package
- [`env_name()`](https://rlang.r-lib.org/reference/env_name.md)
  [`env_label()`](https://rlang.r-lib.org/reference/env_name.md) : Label
  of an environment

## Defused expressions

- [`parse_expr()`](https://rlang.r-lib.org/reference/parse_expr.md)
  [`parse_exprs()`](https://rlang.r-lib.org/reference/parse_expr.md)
  [`parse_quo()`](https://rlang.r-lib.org/reference/parse_expr.md)
  [`parse_quos()`](https://rlang.r-lib.org/reference/parse_expr.md) :
  Parse R code
- [`expr_print()`](https://rlang.r-lib.org/reference/expr_print.md)
  [`expr_deparse()`](https://rlang.r-lib.org/reference/expr_print.md) :
  Print an expression
- [`is_expression()`](https://rlang.r-lib.org/reference/is_expression.md)
  [`is_syntactic_literal()`](https://rlang.r-lib.org/reference/is_expression.md)
  [`is_symbolic()`](https://rlang.r-lib.org/reference/is_expression.md)
  : Is an object an expression?
- [`exprs_auto_name()`](https://rlang.r-lib.org/reference/exprs_auto_name.md)
  [`quos_auto_name()`](https://rlang.r-lib.org/reference/exprs_auto_name.md)
  : Ensure that all elements of a list of expressions are named

### Evaluate

- [`eval_tidy()`](https://rlang.r-lib.org/reference/eval_tidy.md) :
  Evaluate an expression with quosures and pronoun support
- [`eval_bare()`](https://rlang.r-lib.org/reference/eval_bare.md) :
  Evaluate an expression in an environment
- [`exec()`](https://rlang.r-lib.org/reference/exec.md) : Execute a
  function
- [`inject()`](https://rlang.r-lib.org/reference/inject.md) : Inject
  objects in an R expression

### Symbols

- [`sym()`](https://rlang.r-lib.org/reference/sym.md)
  [`syms()`](https://rlang.r-lib.org/reference/sym.md)
  [`data_sym()`](https://rlang.r-lib.org/reference/sym.md)
  [`data_syms()`](https://rlang.r-lib.org/reference/sym.md) : Create a
  symbol or list of symbols
- [`is_symbol()`](https://rlang.r-lib.org/reference/is_symbol.md) : Is
  object a symbol?
- [`as_string()`](https://rlang.r-lib.org/reference/as_string.md) : Cast
  symbol to string

### Calls

- [`call2()`](https://rlang.r-lib.org/reference/call2.md) : Create a
  call
- [`is_call()`](https://rlang.r-lib.org/reference/is_call.md) : Is
  object a call?
- [`call_args()`](https://rlang.r-lib.org/reference/call_args.md)
  [`call_args_names()`](https://rlang.r-lib.org/reference/call_args.md)
  : Extract arguments from a call
- [`call_inspect()`](https://rlang.r-lib.org/reference/call_inspect.md)
  : Inspect a call
- [`call_match()`](https://rlang.r-lib.org/reference/call_match.md) :
  Match supplied arguments to function definition
- [`call_modify()`](https://rlang.r-lib.org/reference/call_modify.md) :
  Modify the arguments of a call
- [`call_name()`](https://rlang.r-lib.org/reference/call_name.md)
  [`call_ns()`](https://rlang.r-lib.org/reference/call_name.md)
  [`is_call_simple()`](https://rlang.r-lib.org/reference/call_name.md) :
  Extract function name or namespace of a call

### Quosures

- [`new_quosure()`](https://rlang.r-lib.org/reference/new_quosure.md)
  [`as_quosure()`](https://rlang.r-lib.org/reference/new_quosure.md)
  [`is_quosure()`](https://rlang.r-lib.org/reference/new_quosure.md) :
  Create a quosure from components
- [`new_quosures()`](https://rlang.r-lib.org/reference/new_quosures.md)
  [`as_quosures()`](https://rlang.r-lib.org/reference/new_quosures.md)
  [`is_quosures()`](https://rlang.r-lib.org/reference/new_quosures.md) :
  Create a list of quosures
- [`quo_is_missing()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  [`quo_is_symbol()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  [`quo_is_call()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  [`quo_is_symbolic()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  [`quo_is_null()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  [`quo_get_expr()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  [`quo_get_env()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  [`quo_set_expr()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  [`quo_set_env()`](https://rlang.r-lib.org/reference/quosure-tools.md)
  : Quosure getters, setters and predicates
- [`quo_squash()`](https://rlang.r-lib.org/reference/quo_squash.md) :
  Squash a quosure

### Formulas

- [`f_rhs()`](https://rlang.r-lib.org/reference/f_rhs.md)
  [`` `f_rhs<-`() ``](https://rlang.r-lib.org/reference/f_rhs.md)
  [`f_lhs()`](https://rlang.r-lib.org/reference/f_rhs.md)
  [`` `f_lhs<-`() ``](https://rlang.r-lib.org/reference/f_rhs.md)
  [`f_env()`](https://rlang.r-lib.org/reference/f_rhs.md)
  [`` `f_env<-`() ``](https://rlang.r-lib.org/reference/f_rhs.md) : Get
  or set formula components
- [`f_text()`](https://rlang.r-lib.org/reference/f_text.md)
  [`f_name()`](https://rlang.r-lib.org/reference/f_text.md)
  [`f_label()`](https://rlang.r-lib.org/reference/f_text.md) : Turn RHS
  of formula into a string or label
- [`new_formula()`](https://rlang.r-lib.org/reference/new_formula.md) :
  Create a formula
- [`is_formula()`](https://rlang.r-lib.org/reference/is_formula.md)
  [`is_bare_formula()`](https://rlang.r-lib.org/reference/is_formula.md)
  : Is object a formula?

## Objects

- [`hash()`](https://rlang.r-lib.org/reference/hash.md)
  [`hash_file()`](https://rlang.r-lib.org/reference/hash.md) : Hashing

### Environments

- [`env()`](https://rlang.r-lib.org/reference/env.md)
  [`new_environment()`](https://rlang.r-lib.org/reference/env.md) :
  Create a new environment
- [`env_print()`](https://rlang.r-lib.org/reference/env_print.md) :
  Pretty-print an environment
- [`env_parent()`](https://rlang.r-lib.org/reference/env_parent.md)
  [`env_tail()`](https://rlang.r-lib.org/reference/env_parent.md)
  [`env_parents()`](https://rlang.r-lib.org/reference/env_parent.md) :
  Get parent environments
- [`env_depth()`](https://rlang.r-lib.org/reference/env_depth.md) :
  Depth of an environment chain
- [`get_env()`](https://rlang.r-lib.org/reference/get_env.md)
  [`set_env()`](https://rlang.r-lib.org/reference/get_env.md)
  [`env_poke_parent()`](https://rlang.r-lib.org/reference/get_env.md) :
  Get or set the environment of an object
- [`env_clone()`](https://rlang.r-lib.org/reference/env_clone.md)
  [`env_coalesce()`](https://rlang.r-lib.org/reference/env_clone.md) :
  Clone or coalesce an environment
- [`env_inherits()`](https://rlang.r-lib.org/reference/env_inherits.md)
  : Does environment inherit from another environment?
- [`is_environment()`](https://rlang.r-lib.org/reference/is_environment.md)
  [`is_bare_environment()`](https://rlang.r-lib.org/reference/is_environment.md)
  : Is object an environment?
- [`as_environment()`](https://rlang.r-lib.org/reference/as_environment.md)
  : Coerce to an environment
- [`current_call()`](https://rlang.r-lib.org/reference/stack.md)
  [`current_fn()`](https://rlang.r-lib.org/reference/stack.md)
  [`current_env()`](https://rlang.r-lib.org/reference/stack.md)
  [`caller_call()`](https://rlang.r-lib.org/reference/stack.md)
  [`caller_fn()`](https://rlang.r-lib.org/reference/stack.md)
  [`caller_env()`](https://rlang.r-lib.org/reference/stack.md)
  [`frame_call()`](https://rlang.r-lib.org/reference/stack.md)
  [`frame_fn()`](https://rlang.r-lib.org/reference/stack.md) : Get
  properties of the current or caller frame
- [`env_browse()`](https://rlang.r-lib.org/reference/env_browse.md)
  [`env_is_browsed()`](https://rlang.r-lib.org/reference/env_browse.md)
  **\[defunct\]** : Browse environments
- [`env_is_user_facing()`](https://rlang.r-lib.org/reference/env_is_user_facing.md)
  : Is frame environment user facing?

### Stack

- [`current_call()`](https://rlang.r-lib.org/reference/stack.md)
  [`current_fn()`](https://rlang.r-lib.org/reference/stack.md)
  [`current_env()`](https://rlang.r-lib.org/reference/stack.md)
  [`caller_call()`](https://rlang.r-lib.org/reference/stack.md)
  [`caller_fn()`](https://rlang.r-lib.org/reference/stack.md)
  [`caller_env()`](https://rlang.r-lib.org/reference/stack.md)
  [`frame_call()`](https://rlang.r-lib.org/reference/stack.md)
  [`frame_fn()`](https://rlang.r-lib.org/reference/stack.md) : Get
  properties of the current or caller frame

### Environment bindings

- [`env_bind()`](https://rlang.r-lib.org/reference/env_bind.md)
  [`env_bind_lazy()`](https://rlang.r-lib.org/reference/env_bind.md)
  [`env_bind_active()`](https://rlang.r-lib.org/reference/env_bind.md)
  [`` `%<~%` ``](https://rlang.r-lib.org/reference/env_bind.md) : Bind
  symbols to objects in an environment
- [`env_unbind()`](https://rlang.r-lib.org/reference/env_unbind.md) :
  Remove bindings from an environment
- [`env_poke()`](https://rlang.r-lib.org/reference/env_poke.md) : Poke
  an object in an environment
- [`env_cache()`](https://rlang.r-lib.org/reference/env_cache.md) :
  Cache a value in an environment
- [`local_bindings()`](https://rlang.r-lib.org/reference/local_bindings.md)
  [`with_bindings()`](https://rlang.r-lib.org/reference/local_bindings.md)
  : Temporarily change bindings of an environment
- [`env_has()`](https://rlang.r-lib.org/reference/env_has.md) : Does an
  environment have or see bindings?
- [`env_get()`](https://rlang.r-lib.org/reference/env_get.md)
  [`env_get_list()`](https://rlang.r-lib.org/reference/env_get.md) : Get
  an object in an environment
- [`env_names()`](https://rlang.r-lib.org/reference/env_names.md)
  [`env_length()`](https://rlang.r-lib.org/reference/env_names.md) :
  Names and numbers of symbols bound in an environment

### Functions

- [`new_function()`](https://rlang.r-lib.org/reference/new_function.md)
  : Create a function
- [`as_function()`](https://rlang.r-lib.org/reference/as_function.md)
  [`is_lambda()`](https://rlang.r-lib.org/reference/as_function.md) :
  Convert to function
- [`is_function()`](https://rlang.r-lib.org/reference/is_function.md)
  [`is_closure()`](https://rlang.r-lib.org/reference/is_function.md)
  [`is_primitive()`](https://rlang.r-lib.org/reference/is_function.md)
  [`is_primitive_eager()`](https://rlang.r-lib.org/reference/is_function.md)
  [`is_primitive_lazy()`](https://rlang.r-lib.org/reference/is_function.md)
  : Is object a function?
- [`fn_fmls()`](https://rlang.r-lib.org/reference/fn_fmls.md)
  [`fn_fmls_names()`](https://rlang.r-lib.org/reference/fn_fmls.md)
  [`fn_fmls_syms()`](https://rlang.r-lib.org/reference/fn_fmls.md)
  [`` `fn_fmls<-`() ``](https://rlang.r-lib.org/reference/fn_fmls.md)
  [`` `fn_fmls_names<-`() ``](https://rlang.r-lib.org/reference/fn_fmls.md)
  : Extract arguments from a function
- [`fn_body()`](https://rlang.r-lib.org/reference/fn_body.md)
  [`` `fn_body<-`() ``](https://rlang.r-lib.org/reference/fn_body.md) :
  Get or set function body
- [`fn_env()`](https://rlang.r-lib.org/reference/fn_env.md)
  [`` `fn_env<-`() ``](https://rlang.r-lib.org/reference/fn_env.md) :
  Return the closure environment of a function
- [`as_closure()`](https://rlang.r-lib.org/reference/as_closure.md) :
  Transform to a closure

### S3

- [`inherits_any()`](https://rlang.r-lib.org/reference/inherits_any.md)
  [`inherits_all()`](https://rlang.r-lib.org/reference/inherits_any.md)
  [`inherits_only()`](https://rlang.r-lib.org/reference/inherits_any.md)
  : Does an object inherit from a set of classes?
- [`zap()`](https://rlang.r-lib.org/reference/zap.md)
  [`is_zap()`](https://rlang.r-lib.org/reference/zap.md) : Create zap
  objects
- [`as_bytes()`](https://rlang.r-lib.org/reference/bytes-class.md)
  [`parse_bytes()`](https://rlang.r-lib.org/reference/bytes-class.md) :
  Human readable memory sizes
- [`new_box()`](https://rlang.r-lib.org/reference/box.md)
  [`is_box()`](https://rlang.r-lib.org/reference/box.md)
  [`unbox()`](https://rlang.r-lib.org/reference/box.md) : Box a value
- [`as_box()`](https://rlang.r-lib.org/reference/as_box.md)
  [`as_box_if()`](https://rlang.r-lib.org/reference/as_box.md) : Convert
  object to a box
- [`done()`](https://rlang.r-lib.org/reference/done.md)
  [`is_done_box()`](https://rlang.r-lib.org/reference/done.md) : Box a
  final value for early termination

### Attributes

- [`set_names()`](https://rlang.r-lib.org/reference/set_names.md) : Set
  names of a vector
- [`names2()`](https://rlang.r-lib.org/reference/names2.md)
  [`` `names2<-`() ``](https://rlang.r-lib.org/reference/names2.md) :
  Get names of a vector
- [`has_name()`](https://rlang.r-lib.org/reference/has_name.md) : Does
  an object have an element with this name?
- [`is_named()`](https://rlang.r-lib.org/reference/is_named.md)
  [`is_named2()`](https://rlang.r-lib.org/reference/is_named.md)
  [`have_name()`](https://rlang.r-lib.org/reference/is_named.md) : Is
  object named?
- [`zap_srcref()`](https://rlang.r-lib.org/reference/zap_srcref.md) :
  Zap source references

### Vectors

- [`lgl()`](https://rlang.r-lib.org/reference/vector-construction.md)
  [`int()`](https://rlang.r-lib.org/reference/vector-construction.md)
  [`dbl()`](https://rlang.r-lib.org/reference/vector-construction.md)
  [`cpl()`](https://rlang.r-lib.org/reference/vector-construction.md)
  [`chr()`](https://rlang.r-lib.org/reference/vector-construction.md)
  [`bytes()`](https://rlang.r-lib.org/reference/vector-construction.md)
  **\[questioning\]** : Create vectors
- [`list2()`](https://rlang.r-lib.org/reference/list2.md)
  [`dots_list()`](https://rlang.r-lib.org/reference/list2.md) : Collect
  dynamic dots in a list
- [`rep_along()`](https://rlang.r-lib.org/reference/rep_along.md)
  [`rep_named()`](https://rlang.r-lib.org/reference/rep_along.md) :
  Create vectors matching the length of a given vector
- [`seq2()`](https://rlang.r-lib.org/reference/seq2.md)
  [`seq2_along()`](https://rlang.r-lib.org/reference/seq2.md) :
  Increasing sequence of integers in an interval

### Type predicates

- [`is_list()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_atomic()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_vector()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_integer()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_double()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_complex()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_character()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_logical()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_raw()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_bytes()`](https://rlang.r-lib.org/reference/type-predicates.md)
  [`is_null()`](https://rlang.r-lib.org/reference/type-predicates.md) :
  Type predicates
- [`is_scalar_list()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_atomic()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_vector()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_integer()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_double()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_complex()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_character()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_logical()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_raw()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_string()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_scalar_bytes()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  [`is_bool()`](https://rlang.r-lib.org/reference/scalar-type-predicates.md)
  : Scalar type predicates
- [`is_bare_list()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_atomic()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_vector()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_double()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_complex()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_integer()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_numeric()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_character()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_logical()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_raw()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_string()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  [`is_bare_bytes()`](https://rlang.r-lib.org/reference/bare-type-predicates.md)
  : Bare type predicates
- [`is_empty()`](https://rlang.r-lib.org/reference/is_empty.md) : Is
  object an empty vector or NULL?
- [`is_integerish()`](https://rlang.r-lib.org/reference/is_integerish.md)
  [`is_bare_integerish()`](https://rlang.r-lib.org/reference/is_integerish.md)
  [`is_scalar_integerish()`](https://rlang.r-lib.org/reference/is_integerish.md)
  : Is a vector integer-like?
- [`is_true()`](https://rlang.r-lib.org/reference/is_true.md)
  [`is_false()`](https://rlang.r-lib.org/reference/is_true.md) : Is
  object identical to TRUE or FALSE?

### Weak references

- [`is_weakref()`](https://rlang.r-lib.org/reference/is_weakref.md) : Is
  object a weak reference?
- [`new_weakref()`](https://rlang.r-lib.org/reference/new_weakref.md) :
  Create a weak reference
- [`wref_key()`](https://rlang.r-lib.org/reference/wref_key.md)
  [`wref_value()`](https://rlang.r-lib.org/reference/wref_key.md) : Get
  key/value from a weak reference object

### Operators

- [`` `%||%` ``](https://rlang.r-lib.org/reference/op-null-default.md) :

  Default value for `NULL`

- [`` `%&&%` ``](https://rlang.r-lib.org/reference/op-null-continuation.md)
  :

  Default value for non-`NULL`

- [`` `%|%` ``](https://rlang.r-lib.org/reference/op-na-default.md) :
  Replace missing values

- [`` `%@%` ``](https://rlang.r-lib.org/reference/op-get-attr.md)
  [`` `%@%<-`() ``](https://rlang.r-lib.org/reference/op-get-attr.md) :
  Infix attribute accessor and setter