# RELAX NG Compact Syntax Grammar
# Description: Google Contacts: feed of contact groups

namespace app = "http://www.w3.org/2007/app"
namespace atom = "http://www.w3.org/2005/Atom"
namespace gContact = "http://schemas.google.com/contact/2008"
namespace gd = "http://schemas.google.com/g/2005"
namespace openSearch = "http://a9.com/-/spec/opensearch/1.1/"

start = contacts_contactGroupFeed | contacts_contactGroupEntry


# Describes an author

atom_author = element atom:author { attribute xml:lang { xsd:string }?, (
    atom_email? &
    atom_name &
    atom_uri? ) }


# Describes a contact group entry

contacts_contactGroupEntry = element atom:entry {
    attribute gd:etag { xsd:string }?,
    ( app_edited? &
    atom_content? &
    atom_id &
    atom_link+ &
    atom_updated &
    contacts_contactGroupKind &
    contacts_systemGroup? &
    element atom:title { atom_textConstruct } &
    gdata_deleted? &
    gdata_extendedProperty* ) }


# Describes a contact group feed

contacts_contactGroupFeed = element atom:feed {
    attribute gd:etag { xsd:string }?,
    ( atom_author+ &
    atom_generator &
    atom_id &
    atom_link+ &
    atom_updated &
    contacts_contactGroupEntry* &
    contacts_contactGroupKind &
    element atom:title { atom_textConstruct } &
    opensearch_itemsPerPage &
    opensearch_startIndex &
    opensearch_totalResults ) }


# Describes a contact group kind

contacts_contactGroupKind = element atom:category {
    attribute scheme { "http://schemas.google.com/g/2005#kind" },
    attribute term { "http://schemas.google.com/contact/2008#group" } }


# Describes a content

atom_content = element atom:content {
    attribute src { xsd:string }?,
    attribute type { xsd:string }?,
    attribute xml:lang { xsd:string }?,
    xsd:string? }


# Denotes an entry has been deleted

gdata_deleted = element gd:deleted { empty }


# Value of the app:edited tag

app_edited = element app:edited { (xsd:date | xsd:dateTime) }


# Describes an author's email address

atom_email = element atom:email { xsd:string }


# Stores a limited amount of custom data as an auxiliary property of the
# enclosing entity

gdata_extendedProperty = element gd:extendedProperty {
    attribute name { xsd:string },
    attribute realm { xsd:string }?,
    attribute value { xsd:string }?,
    anyElement? }


# Describes the generator

atom_generator = element atom:generator {
    attribute uri { xsd:string }?,
    attribute version { xsd:string }?,
    xsd:string }


# Describes a unique identifier

atom_id = element atom:id { xsd:string }


# Describes the number of items that will be returned per page for paged feeds

opensearch_itemsPerPage = element openSearch:itemsPerPage { xsd:int }


# Describes an external link type

atom_link = element atom:link {
    attribute href { xsd:string },
    attribute hreflang { xsd:string }?,
    attribute length { xsd:long }?,
    attribute rel { xsd:string }?,
    attribute title { xsd:string }?,
    attribute type { xsd:string }?,
    attribute xml:lang { xsd:string }? }


# Describes an author's human-readable name

atom_name = element atom:name { xsd:string }


# Describes the starting index of the contained entries for paged feeds

opensearch_startIndex = element openSearch:startIndex { xsd:int }


# Element that if present marks that a group is a system one

contacts_systemGroup = element gContact:systemGroup {
    attribute id { xsd:string } }


# Describes a text construct containing either plain text, HTML, or XHTML

atom_textConstruct = attribute src { xsd:string }?,
    attribute type { xsd:string }?,
    attribute xml:lang { xsd:string }?,
    xsd:string?


# Describes the total number of results associated with this feed

opensearch_totalResults = element openSearch:totalResults { xsd:int }


# Describes a last updated timestamp

atom_updated = element atom:updated { (xsd:date | xsd:dateTime) }


# Describes the URI associated with an author

atom_uri = element atom:uri { xsd:string }

# defines any arbitrary XML element

anyElement = element * { (
    attribute * { text }
    | text
    | anyElement )* }