Learn R Programming

⚠️There's a newer version (1.1.6) of this package.Take me there.

rlang

Important: The rlang API is still maturing. Please see ?rlang::lifecycle for the list of functions that are considered stable.

Overview

The rlang package provides tools to work with core language features of R and the tidyverse:

The tidy eval framework, which is a well-founded system for non-standard evaluation built on quasiquotation (!!) and quosures (quo()).
Consistent tools for working with base types. Note that overall this is a work in progress that is still in flux:
- Vectors, including construction (lgl(), int(), ...) coercion (as_logical(), as_character(), ...), and predicates (is_logical(), is_character()).
- Language objects, such as calls (lang()) and symbols (sym()).
- Attributes, e.g. set_names().
- Functions, e.g. new_function(), as_function(). The latter supports the purrr-style formula notation for lambda functions.
- Environments, e.g. env(), env_has(), env_get(), env_bind(), env_unbind().
A comprehensive set of predicates to determine if an object satisfies various conditions, e.g. has_length(), is_list(), is_empty().
The condition (message, warning, error) and restart system.

Installation

You can install the released version of rlang from CRAN with:

install.packages("rlang")

Or install the development version from github with:

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

Copy Link

Version

Install

install.packages('rlang')

Monthly Downloads

1,760,922

Version

0.2.0

License

GPL-3

Issues

Pull Requests

Stars

Forks

Repository

https://github.com/r-lib/rlang

Homepage

http://rlang.tidyverse.org

Maintainer

Lionel Henry

Last Published

February 20th, 2018

Functions in rlang (0.2.0)

Test for missing values

Extract function from a call

dots_definitions

Capture definition objects

How many arguments are currently forwarded in dots?

Evaluate dots with preliminary splicing

Evaluate an expression with quosures and pronoun support

Evaluate an expression in an environment

Flatten or squash a list of lists into a simpler vector

Duplicate an R object

Get or set function body

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

Is object a function?

Format a type for error messages

Is object identical to TRUE or FALSE?

Is object a frame?

Generate or handle a missing argument

op-null-default

Default value for NULL

Replace missing values

Modify a vector

Squash a quosure

Format quosures for printing or labelling

Create a data mask

scalar-type-predicates

Scalar type predicates

Coerce to an environment

scoped_bindings

Temporarily change bindings of an environment

set_chr_encoding

Set encoding of a string or character vector

Extract arguments from a call

Set and get an expression

Coerce to an environment

type-predicates

Type predicates

Catch a condition

Match an argument to a character vector

Convert to function or closure

chr_unserialise_unicode

Translate unicode points to UTF-8

Coerce object to quosure

Coerce to a raw vector

Base type of an object

bare-type-predicates

Bare type predicates

as_utf8_character

Coerce to a character vector and attempt encoding conversion

Mask bindings by defining symbols deeper in a scope

Clone an environment

Names of symbols bound in an environment

call_standardise

Standardise a call

Get parent environments

Deprecated condition constructors

Return the closure environment of a function

Coerce to pairlist

Create an overscope

Create a dictionary

Get the environment of the caller frame

Modify the arguments of a call

Extract function name of a call

Extract arguments from a function

Create a condition object

Signal a condition

Get the empty environment

Create a new environment

Bind symbols to objects in an environment

Tidy evaluation in a custom environment

Bind lazy or active bindings

Create an exiting or in place handler

Process unquote operators in a captured expression

Does an environment have or see bindings?

Does environment inherit from another environment?

Turn an expression to a label

Is object a call?

Invoke a function with a list of arguments

Is a package installed in the library?

Print an expression

Depth of an environment chain

Get an object in an environment

Is a vector integer-like?

Does an object have an element with this name?

Is an object copyable?

exprs_auto_name

Ensure that list of expressions are all named

Does an object inherit from a set of classes?

Is object an empty vector or NULL?

Is object a stack?

Is object a call?

Is object a symbol?

Get names of a vector

new-vector-along

Create vectors matching the length of a given vector

Get or set formula components

Remove bindings from an environment

Poke an object in an environment

Is object a condition?

Helpers for pairlist and language nodes

Is an object callable?

Turn RHS of formula into a string or label

Is object a formula?

Is an object an expression?

Get the namespace of a package

Is an object a namespace environment?

Squash a quosure

Quosure getters, setters and testers

Is object named?

Restarts utilities

Create vectors matching a given length

Create a new call from components

overscope_eval_next

Evaluate next quosure in a data mask

mut_utf8_locale

Set the locale's codeset for testing

Mutate node components

Get or set the environment of an object

Is object a node or pairlist?

Jump to a muffling restart

Increasing sequence of integers in an interval

How long is an object?

Is object an environment?

Is an object an expression?

Life cycle of the rlang package

Evaluate an expression within a given environment

vector-construction

Add attributes to an object

Infix attribute accessor

Definition operator

vector-old-ctors

Retired vector construction by length

Parse text into a quosure

Create a restarting handler

Prepend a vector

Scoped environments

Change global options

Trim top call layers from the evaluation stack

Call stack information

Set names of a vector

Test for or coerce to quosure-like objects

Is an object referencing another?

Establish handlers on the stack

Collect dots tidily

Poke values into a vector

Return the head or tail of a call

vector-coercion

Coerce an object to a base type

Create a formula

Manipulate or access a call

Data pronoun for tidy evaluation

Create a function

Jump to or from a frame

Name of a primitive function

Quasiquotation of an expression

Jump to the abort restart

Create a string

Establish a restart point on the stack

Dispatch on call type

Dispatch on base types

Create a symbol or list of symbols

Signal an error, warning, or message