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.

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.

See also

Examples

# as_quosure() converts expressions or any R object to a validly # scoped quosure: env <- env(var = "thing") as_quosure(quote(var), env)
#> <quosure> #> expr: ^var #> env: 0x88de8b8
# The environment is ignored for formulas: as_quosure(~foo, env)
#> <quosure> #> expr: ^foo #> env: 0x8f90ce0
as_quosure(~foo)
#> <quosure> #> expr: ^foo #> env: 0x8f90ce0
# However you must supply it for symbols and calls: try(as_quosure(quote(var)))
#> <quosure> #> expr: ^var #> env: 0x8f90ce0