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 = caller_env())

new_quosure(expr, env = caller_env())

Arguments

x

An object to convert. Either an expression or a formula.

env

The original context of the context expression.

expr

The expression wrapped by the quosure.

Life cycle

  • Like the rest of the rlang package, new_quosure() and as_quosure() are maturing.

  • 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

quo(), is_quosure()

Examples

# as_quosure() converts expressions or any R object to a validly # scoped quosure: as_quosure(quote(expr), base_env())
#> <quosure> #> expr: ^expr #> env: 0x7f828b01dd08
as_quosure(10L, base_env())
#> <quosure> #> expr: ^10L #> env: empty
# Sometimes you get unscoped formulas because of quotation: f <- ~~expr inner_f <- f_rhs(f) str(inner_f)
#> language ~expr
# In that case testing for a scoped formula returns FALSE: is_formula(inner_f, scoped = TRUE)
#> [1] FALSE
# With as_quosure() you ensure that this kind of unscoped formulas # will be granted a default environment: as_quosure(inner_f, base_env())
#> <quosure> #> expr: ^~expr #> env: 0x7f828b01dd08