opentofu/internal/addrs/referenceable.go
Martin Atkins f3a57db293 addrs: UniqueKey and UniqueKeyer
Many times now we've seen situations where we need to use addresses
as map keys, but not all of our address types are comparable and thus
we tend to end up using string representations as keys instead.

That's problematic because conversion to string uses type information
and some of the address types have string representations that are
ambiguous with one another.

UniqueKey therefore represents an opaque key that is unique for each
functionally-distinct address across all types that implement
UniqueKeyer.

For this initial commit I've implemented UniqueKeyer only for the
Referenceable family of types. These are an easy case because they
were all already comparable (intentionally) anyway. Later commits
can implement UniqueKeyer for other types that are not naturally
comparable, such as any which include a ModuleInstance.

This also includes a new type addrs.Set which wraps a map as a set
of addresses, using the unique keys to ensure that there can be only
one element for each distinct address.
2021-07-14 17:37:48 -07:00

24 lines
654 B
Go

package addrs
// Referenceable is an interface implemented by all address types that can
// appear as references in configuration language expressions.
type Referenceable interface {
// All implementations of this interface must be covered by the type switch
// in lang.Scope.buildEvalContext.
referenceableSigil()
// All Referenceable address types must have unique keys.
UniqueKeyer
// String produces a string representation of the address that could be
// parsed as a HCL traversal and passed to ParseRef to produce an identical
// result.
String() string
}
type referenceable struct {
}
func (r referenceable) referenceableSigil() {
}