code: function EarleyItem(parameters) {
    // A unique identifier is constructed from rule, dot and from
    this.id = "Earley(" + parameters.rule.lhs + "->" + parameters.rule.rhs + 
      ", " + parameters.dot + ", " + parameters.from + ", " + parameters.to +")";
    logger.debug("EarleyItem: " + this.id);
    this.name = parameters.rule.lhs;
    this.children = [];
  
    this.data = {};
    this.data.rule = parameters.rule;
    this.data.dot = parameters.dot;
    this.data.from = parameters.from;
    this.data.to = parameters.to;
    if (global.config.UNIFICATION) {
      this.data.fs = parameters.fs;
    }
  }
docs: Creates an item; dot is an index in the RHS of the rule, from is the starting point in the sentence Data structure is prepared for InfoVis