Upgrade hcl to v2

Signed-off-by: Patrick Van Stee <patrick@vanstee.me>

vendor/github.com/zclconf/go-cty/cty/value.go

@@ -0,0 +1,108 @@
+package cty
+
+// Value represents a value of a particular type, and is the interface by
+// which operations are executed on typed values.
+//
+// Value has two different classes of method. Operation methods stay entirely
+// within the type system (methods accept and return Value instances) and
+// are intended for use in implementing a language in terms of cty, while
+// integration methods either enter or leave the type system, working with
+// native Go values. Operation methods are guaranteed to support all of the
+// expected short-circuit behavior for unknown and dynamic values, while
+// integration methods may not.
+//
+// The philosophy for the operations API is that it's the caller's
+// responsibility to ensure that the given types and values satisfy the
+// specified invariants during a separate type check, so that the caller is
+// able to return errors to its user from the application's own perspective.
+//
+// Consequently the design of these methods assumes such checks have already
+// been done and panics if any invariants turn out not to be satisfied. These
+// panic errors are not intended to be handled, but rather indicate a bug in
+// the calling application that should be fixed with more checks prior to
+// executing operations.
+//
+// A related consequence of this philosophy is that no automatic type
+// conversions are done. If a method specifies that its argument must be
+// number then it's the caller's responsibility to do that conversion before
+// the call, thus allowing the application to have more constrained conversion
+// rules than are offered by the built-in converter where necessary.
+type Value struct {
+	ty Type
+	v  interface{}
+}
+
+// Type returns the type of the value.
+func (val Value) Type() Type {
+	return val.ty
+}
+
+// IsKnown returns true if the value is known. That is, if it is not
+// the result of the unknown value constructor Unknown(...), and is not
+// the result of an operation on another unknown value.
+//
+// Unknown values are only produced either directly or as a result of
+// operating on other unknown values, and so an application that never
+// introduces Unknown values can be guaranteed to never receive any either.
+func (val Value) IsKnown() bool {
+	if val.IsMarked() {
+		return val.unmarkForce().IsKnown()
+	}
+	return val.v != unknown
+}
+
+// IsNull returns true if the value is null. Values of any type can be
+// null, but any operations on a null value will panic. No operation ever
+// produces null, so an application that never introduces Null values can
+// be guaranteed to never receive any either.
+func (val Value) IsNull() bool {
+	if val.IsMarked() {
+		return val.unmarkForce().IsNull()
+	}
+	return val.v == nil
+}
+
+// NilVal is an invalid Value that can be used as a placeholder when returning
+// with an error from a function that returns (Value, error).
+//
+// NilVal is *not* a valid error and so no operations may be performed on it.
+// Any attempt to use it will result in a panic.
+//
+// This should not be confused with the idea of a Null value, as returned by
+// NullVal. NilVal is a nil within the *Go* type system, and is invalid in
+// the cty type system. Null values *do* exist in the cty type system.
+var NilVal = Value{
+	ty: Type{typeImpl: nil},
+	v:  nil,
+}
+
+// IsWhollyKnown is an extension of IsKnown that also recursively checks
+// inside collections and structures to see if there are any nested unknown
+// values.
+func (val Value) IsWhollyKnown() bool {
+	if val.IsMarked() {
+		return val.unmarkForce().IsWhollyKnown()
+	}
+
+	if !val.IsKnown() {
+		return false
+	}
+
+	if val.IsNull() {
+		// Can't recurse into a null, so we're done
+		return true
+	}
+
+	switch {
+	case val.CanIterateElements():
+		for it := val.ElementIterator(); it.Next(); {
+			_, ev := it.Element()
+			if !ev.IsWhollyKnown() {
+				return false
+			}
+		}
+		return true
+	default:
+		return true
+	}
+}