NewRule creates a new Rule.

ParseAbsoluteLabel parses a label string in absolute form, such as "//aaa/bbb:ccc/ddd" or "//aaa/bbb".

ParseRelativeLabel parses a label, not necessarily absolute, relative to some package.

Package represents a Bazel Package.

PackageGroup represents a package_group() function call in a BUILD file.

Rule represents a Bazel Rule.

UnknownAttributeValue is used as a value in Rule.Attrs to represent an attribute that is present, but whose value we can't represent.

Label is a rule's label, e.g.