@inproceedings{costagliola-chang-1991-parsing,
    title = "Parsing 2-{D} Languages with Positional Grammars",
    author = "Costagliola, Gennaro  and
      Chang, Shi-Kuo",
    editor = "Tomita, Masaru  and
      Kay, Martin  and
      Berwick, Robert  and
      Hajicova, Eva  and
      Joshi, Aravind  and
      Kaplan, Ronald  and
      Nagao, Makoto  and
      Wilks, Yorick",
    booktitle = "Proceedings of the Second International Workshop on Parsing Technologies",
    month = feb # " 13-25",
    year = "1991",
    address = "Cancun, Mexico",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/ingest-emnlp/1991.iwpt-1.27/",
    pages = "235--243",
    abstract = "In this paper we will present a way to parse two-dimensional languages using LR parsing tables. To do this we describe two-dimensional (positional) grammars as a generalization of the context-free string grammars. The main idea behind this is to allow a traditional LR parser to choose the next symbol to parse from a two-dimensional space. Cases of ambiguity are analyzed and some ways to avoid them are presented. Finally, we construct a parser for the two-dimensional arithmetic expression language and implement it by using the tool Yacc."
}