Quoting assignment operator.
The colon-equals operator is typically used in DSL packages like
data.table. It is exported in rlang as a
~. This makes it a quoting operator that can be
shared between packages for computing on the language. Since it
effectively creates formulas, it is immediately compatible with
rlang's formulas and interpolation features.
- An object to test.
# This is useful to provide an alternative way of specifying # arguments in DSLs: fn <- function(...) ..1 f <- fn(arg := foo(bar) + baz) is_formula(f) f_lhs(f) f_rhs(f) # A predicate is provided to distinguish formulas from the # colon-equals operator: is_colon_equals(a := b) is_colon_equals(a ~ b)