Initial QSfera import

Server/vendor/github.com/open-policy-agent/opa/ast/unify.go

@@ -0,0 +1,14 @@
+// Copyright 2016 The OPA Authors.  All rights reserved.
+// Use of this source code is governed by an Apache2
+// license that can be found in the LICENSE file.
+
+package ast
+
+import v1 "github.com/open-policy-agent/opa/v1/ast"
+
+// Unify returns a set of variables that will be unified when the equality expression defined by
+// terms a and b is evaluated. The unifier assumes that variables in the VarSet safe are already
+// unified.
+func Unify(safe VarSet, a *Term, b *Term) VarSet {
+	return v1.Unify(safe, a, b)
+}