This small S3 class provides methods for [ and c() and ensures
the following invariants:
The list only contains quosures.
It is always named, possibly with a vector of empty strings.
new_quosures() takes a list of quosures and adds the quosures
class and a vector of empty names if needed. as_quosures() calls
as_quosure() on all elements before creating the quosures
object.
new_quosures(x)as_quosures(x, env, named = FALSE)
is_quosures(x)
A list of quosures or objects to coerce to quosures.
The default environment for the new quosures.
Whether to name the list with quos_auto_name().