rlang v0.2.1
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Functions for Base Types and Core R and 'Tidyverse' Features
A toolbox for working with base types, core R features
like the condition system, and core 'Tidyverse' features like tidy
evaluation.
Readme
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)
Functions in rlang
| Name | Description | |
| call_args | Extract arguments from a call | |
| catch_cnd | Catch a condition | |
| env_depth | Depth of an environment chain | |
| deprecated-cnd | Deprecated condition constructors | |
| dots_n | How many arguments are currently forwarded in dots? | |
| cnd_signal | Signal a condition | |
| env_bind | Bind symbols to objects in an environment | |
| env_names | Names of symbols bound in an environment | |
| dots_definitions | Capture definition objects | |
| env_bind_exprs | Bind lazy or active bindings | |
| chr_unserialise_unicode | Translate unicode points to UTF-8 | |
| call_standardise | Standardise a call | |
| dictionary | Create a dictionary | |
| cnd | Create a condition object | |
| expr_print | Print an expression | |
| eval_bare | Evaluate an expression in an environment | |
| eval_tidy | Evaluate an expression with quosures and pronoun support | |
| call_inspect | Inspect a call | |
| exprs_auto_name | Ensure that list of expressions are all named | |
| env_parent | Get parent environments | |
| env_get | Get an object in an environment | |
| f_text | Turn RHS of formula into a string or label | |
| dots_values | Evaluate dots with preliminary splicing | |
| f_rhs | Get or set formula components | |
| get_env | Get or set the environment of an object | |
| flatten | Flatten or squash a list of lists into a simpler vector | |
| has_length | How long is an object? | |
| is_callable | Is an object callable? | |
| fn_body | Get or set function body | |
| is_quosureish | Test for or coerce to quosure-like objects | |
| caller_env | Get the environment of the caller frame | |
| empty_env | Get the empty environment | |
| is_condition | Is object a condition? | |
| duplicate | Duplicate an R object | |
| is_reference | Is an object referencing another? | |
| env_unbind | Remove bindings from an environment | |
| env_poke | Poke an object in an environment | |
| is_frame | Is object a frame? | |
| frame_position | Find the position or distance of a frame on the evaluation stack | |
| fn_env | Return the closure environment of a function | |
| env | Create a new environment | |
| lifecycle | Life cycle of the rlang package | |
| missing | Missing values | |
| eval_tidy_ | Tidy evaluation in a custom environment | |
| env_bury | Mask bindings by defining symbols deeper in a scope | |
| fn_fmls | Extract arguments from a function | |
| env_clone | Clone an environment | |
| exiting | Create an exiting or in place handler | |
| new_node | Helpers for pairlist and language nodes | |
| has_name | Does an object have an element with this name? | |
| ns_env | Get the namespace of a package | |
| is_env | Is object an environment? | |
| inherits_any | Does an object inherit from a set of classes? | |
| env_has | Does an environment have or see bindings? | |
| friendly_type | Format a type for error messages | |
| is_copyable | Is an object copyable? | |
| parse_quosure | Parse text into a quosure | |
| prepend | Prepend a vector | |
| set_expr | Set and get an expression | |
| set_chr_encoding | Set encoding of a string or character vector | |
| scoped_options | Change global options | |
| is_expr | Is an object an expression? | |
| tidy-dots | Collect dots tidily | |
| is_function | Is object a function? | |
| tidyeval-data | Data pronoun for tidy evaluation | |
| scoped_env | Scoped environments | |
| is_stack | Is object a stack? | |
| is_installed | Is a package installed in the library? | |
| is_true | Is object identical to TRUE or FALSE? | |
| env_inherits | Does environment inherit from another environment? | |
| expr_interp | Process unquote operators in a captured expression | |
| names2 | Get names of a vector | |
| is_symbol | Is object a symbol? | |
| new-vector-along | Create vectors matching the length of a given vector | |
| is_integerish | Is a vector integer-like? | |
| new_formula | Create a formula | |
| is_empty | Is object an empty vector or NULL? | |
| new_function | Create a function | |
| is_lang | Is object a call? | |
| op-get-attr | Infix attribute accessor | |
| op-definition | Definition operator | |
| is_named | Is object named? | |
| quo_expr | Squash a quosure | |
| quo_squash | Squash a quosure | |
| quosure | Quosure getters, setters and testers | |
| modify | Modify a vector | |
| missing_arg | Generate or handle a missing argument | |
| rst_list | Restarts utilities | |
| op-na-default | Replace missing values | |
| expr_label | Turn an expression to a label | |
| invoke | Invoke a function with a list of arguments | |
| quo_label | Format quosures for printing or labelling | |
| op-null-default | Default value for NULL | |
| is_call | Is object a call? | |
| is_expression | Is an object an expression? | |
| stack | Call stack information | |
| scalar-type-predicates | Scalar type predicates | |
| type-predicates | Type predicates | |
| stack_trim | Trim top call layers from the evaluation stack | |
| rst_muffle | Jump to a muffling restart | |
| lang | Create a call | |
| is_formula | Is object a formula? | |
| is_namespace | Is an object a namespace environment? | |
| prim_name | Name of a primitive function | |
| scoped_bindings | Temporarily change bindings of an environment | |
| is_pairlist | Is object a node or pairlist? | |
| mut_node_car | Mutate node components | |
| string | Create a string | |
| switch_lang | Dispatch on call type | |
| with_env | Evaluate an expression within a given environment | |
| type_of | Base type of an object | |
| mut_utf8_locale | Set the locale's codeset for testing | |
| lang_head | Return the head or tail of a call | |
| new-vector | Create vectors matching a given length | |
| lang_modify | Manipulate or access a call | |
| quasiquotation | Quasiquotation of an expression | |
| with_handlers | Establish handlers on the stack | |
| overscope_eval_next | Evaluate next quosure in a data mask | |
| new_call | Create a new call from components | |
| switch_type | Dispatch on base types | |
| sym | Create a symbol or list of symbols | |
| quotation | Quotation | |
| parse_quosures | Parse R code | |
| return_from | Jump to or from a frame | |
| restarting | Create a restarting handler | |
| set_names | Set names of a vector | |
| splice | Splice lists | |
| seq2 | Increasing sequence of integers in an interval | |
| rst_abort | Jump to the abort restart | |
| set_attrs | Add attributes to an object | |
| vector-construction | Create vectors | |
| vector-old-ctors | Retired vector construction by length | |
| vec_poke_n | Poke values into a vector | |
| with_restarts | Establish a restart point on the stack | |
| vector-coercion | Coerce an object to a base type | |
| abort | Signal an error, warning, or message | |
| as_data_mask | Create a data mask | |
| as_environment | Coerce to an environment | |
| are_na | Test for missing values | |
| as_function | Convert to function or closure | |
| arg_match | Match an argument to a character vector | |
| as_env | Coerce to an environment | |
| bare-type-predicates | Bare type predicates | |
| call_fn | Extract function from a call | |
| call_modify | Modify the arguments of a call | |
| as_overscope | Create an overscope | |
| call2 | Create a call | |
| as_utf8_character | Coerce to a character vector and attempt encoding conversion | |
| as_bytes | Coerce to a raw vector | |
| box | Box a value | |
| as_quosure | Coerce object to quosure | |
| as_pairlist | Coerce to pairlist | |
| call_name | Extract function name of a call | |
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Details
| License | GPL-3 |
| LazyData | true |
| ByteCompile | true |
| RoxygenNote | 6.0.1 |
| URL | http://rlang.tidyverse.org, https://github.com/r-lib/rlang |
| BugReports | https://github.com/r-lib/rlang/issues |
| NeedsCompilation | yes |
| Packaged | 2018-05-30 13:14:55 UTC; lionel |
| Repository | CRAN |
| Date/Publication | 2018-05-30 14:23:07 UTC |
| suggests | covr , crayon , knitr , methods , pillar , rmarkdown (>= 0.2.65) , testthat |
| depends | R (>= 3.1.0) |
| Contributors | RStudio, Hadley Wickham |
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