I would reword it as "the primary representation is also a data structure literal in the language itself". I think "literal" is basically what they mean by "pri

I would reword it as "the primary representation is also a data structure literal in the language itself". I think "literal" is basically what they mean by "primitive type", i.e. there is first-class syntax to create the structure. Another example of a homoiconic language is XSLT, where the syntax of the language is based on XML, but it also has XML literals.