Document-based operators

These operators use a scope based on the whole document which could be consider 'all' group-scope.

Such operators are:

• require(featureName)
• document[keyStr]
• attribute(attributeNameStr).keys
• document.keys()
• return
• function
• dictionary(dictionaryStr)
• attribute(attributeNameStr)[keyStr]
• document()
• type(attributeNameStr)
• version()
• locale([localeCodeStr])