public void addStruct(ParsedStruct struct) {
        String sName = struct.name();
        verifyThat(! docStructs.containsKey(sName), "already has struct", sName);
        docStructs.put(sName, struct);
        struct.tagOwner(this);
    }
This class holds the extracted information after parsing a
"document" block in a schema (.sd) file, using simple data
structures as far as possible.  Do not put advanced logic here!
@author arnej27959
config-model/src/main/java/com/yahoo/schema/parser/ParsedDocument.java