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rlang

The rlang package provides tools to work with expressions and calls in R. It is a fork of lazyeval that is larger in scope than just non-standard evaluation.

Installation

Install the development version from github with:

# install.packages("devtools")
devtools::install_github("hadley/rlang", build_vignettes = TRUE)

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Version

Install

install.packages('rlang')

Monthly Downloads

2,046,302

Version

0.0.0.9000

License

GPL-3

Maintainer

Hadley Wickham

Last Published

April 11th, 2025

Functions in rlang (0.0.0.9000)

as_name

Coerce an object to a name or call.
as_function

Coerce to function.
along

Helper to create vectors with matching length.
as_quoted_f

Coerce quoted expressions to quoted formula.
as_env

Coerce to an environment.
abort

Signal an error, warning, or message.
arg_expr

Find the expression associated with an argument
arg_capture

Capture an expression and evaluation environment.
arg_inspect

Inspect an argument
arg_missing

Generate or handle a missing argument
call_inspect

Inspect a call.
call_new

Create a call by "hand"
call_fn_name

Extract function name of a call
call_fn

Extract function from a call
cnd_new

Create a condition object.
call_modify

Modify the arguments of a call.
ast_

Display a call (or expression) as a tree.
call_standardise

Standardise a call against formal arguments
bare-type-predicates

Bare type predicates
call_args

Extract arguments from a call
env_bury

Bury bindings and define objects in new scope.
env_caller

Get the environment of the caller frame.
dots_inspect

Inspect dots
env_assign

Assign objects to an environment.
env_assign_lazily

Assign a promise to an environment.
cnd_signal

Signal a condition.
env_namespace

Get the namespace of a package.
env_clone

Clone an environment.
env_scoped

Scope environments
env_empty

Get the empty environment.
env<-

Assignment operator for environments.
env

Get an environment.
is_condition

Is object a condition?
frame_position

Find the position or distance of a frame on the evaluation stack.
frame_dots

Extract dots
f_list

Build a named list from the LHS of formulas
is_dot_symbol

Is object a ..n symbol?
f_rhs

Get/set formula components.
f_new

Create a formula object by "hand".
f_text

Turn RHS of formula into a string/label.
is_formula

Is object a formula?
is_frame

Is object a frame?
fn_new

Create a function by "hand"
is_function

Is object a function?
fn_fmls

Extract arguments from a function
names2

Get names of a vector.
modify

Modify a vector.
is_lang

Is an object a language object?
new-vectors

Create new vectors.
op-colon-equals

Quoting assignment operator.
restarting

Create a restarting handler.
return_from

Jump to or from a frame.
rst_list

Restarts utilities.
rst_abort

Jump to the abort restart.
with_attributes

Add attributes to an object.
type-predicates

Type predicates
fn_env

Return the closure environment of a function.
f_unwrap

Unwrap a formula
invoke

Invoke a function with a list of arguments.
is_call

Is object a call?
is_stack

Is object a stack?
is_named

Is object named?
parse_expr

Parse R code.
op-null-default

Default value for NULL.
env_has

Does an environment have or see bindings?
env_get

Get an object from an environment.
with_restarts

Establish a restart point on the stack.
stack

Call stack information
stack_trim

Trim top call layers from the evaluation stack.
env_set

Set an environment.
env_unbind

Remove bindings from an environment.
op-get-attr

Infix attribute accessor.
op-na-default

Replace missing values.
exiting

Create an exiting or in place handler.
interp

Interpolate a formula
has_length

How long is an object?
f_eval

Evaluate a formula
is_env

Is object an environment?
is_empty

Is object an empty vector or NULL?
prepend

Prepend a vector.
splice

Splice objects and lists of objects into a list
set_names

Set names of a vector.
prim_name

Name of a primitive function
is_true

Is object identical to TRUE or FALSE?
with_env

Evaluate an expression within a given environment.
scalar-type-predicates

Scalar type predicates
rst_muffle

Jump to a muffling restart.
missing

Missing values.
with_handlers

Establish handlers on the stack.
data_source

Evaluate a formula
f_quote

Interpolate a quoted expression.
expr_eval

Evaluate an expression in an environment.
expr_label

Turn an expression to a label.
tidy_capture

Capture an expression and evaluation environment.
tidy_eval_env

Create a tidy evaluation environment.
tidy_quote_expr

Untidy quotation of an expression.
tidy_quote

Tidy quotation of an expression.
tidy_eval

Evaluate a formula
tidy_interp

Process unquote operators in a captured expression.
empty_env

Get the empty environment.
env_assign_promise

Assign a promise to an environment.
caller_env

Get the environment of the caller frame.
as_fquote

Coerce quoted expressions to quoted formula.
new_f

Create a formula object by "hand".
new_fn

Create a function by "hand"
ns_env

Get the namespace of a package.
new_cnd

Create a condition object.
new_call

Create a call by "hand"
scoped_env

Scope environments
as_tidy_quote

Coerce expressions to a tidy formula quote.
tidy_dots

Capture dots.
op-definition

Definition operator.
new_tidy_quote

Create a tidy quote by hand.
new_formula

Create a formula object by "hand".
is_integerish

Is a vector integer-like?
has_name

Does an object have an element with this name?