rlang: as_quosure – R documentation

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as_quosure

Coerce object to quosure

Description

While new_quosure() wraps any R object (including expressions, formulas, or other quosures) into a quosure, as_quosure() converts formulas and quosures and does not double-wrap.

Usage

as_quosure(x, env = NULL)

new_quosure(expr, env = caller_env())

Arguments

`x`	An object to convert. Either an expression or a formula.
`env`	The environment in which the expression should be evaluated. Only used for symbols and calls. This should typically be the environment in which the expression was created.
`expr`	The expression wrapped by the quosure.

Life cycle

as_quosure() now requires an explicit default environment for creating quosures from symbols and calls.
as_quosureish() is deprecated as of rlang 0.2.0. This function assumes that quosures are formulas which is currently true but might not be in the future.

Examples

# as_quosure() converts expressions or any R object to a validly
# scoped quosure:
env <- env(var = "thing")
as_quosure(quote(var), env)


# The environment is ignored for formulas:
as_quosure(~foo, env)
as_quosure(~foo)

# However you must supply it for symbols and calls:
try(as_quosure(quote(var)))

rlang

Functions for Base Types and Core R and 'Tidyverse' Features

v0.4.11

MIT + file LICENSE

Authors

Lionel Henry [aut, cre], Hadley Wickham [aut], mikefc [cph] (Hash implementation based on Mike's xxhashlite), Yann Collet [cph] (Author of the embedded xxHash library), RStudio [cph]

Initial release