Operator precedence omega-languages

Recent literature extended the analysis of \u3c9-languages from the regular ones to various classes of languages with \u201cvisible syntax structure\u201d, such as visibly pushdown languages (VPLs). Operator precedence languages (OPLs), instead, were originally defined to support deterministic parsing and exhibit interesting relations with these classes of languages: OPLs strictly include VPLs, enjoy all relevant closure properties and have been characterized by a suitable automata family and a logic notation. We introduce here operator precedence \u3c9-languages (\u3c9OPLs), investigating various acceptance criteria and their closure properties. Whereas some properties are natural extensions of those holding for regular languages, others require novel investigation techniques. Application-oriented examples show the gain in expressiveness and verifiability offered by \u3c9OPLs w.r.t. smaller classes