示例#1
0
  public static void generateParser(Grammar g, String target) throws FileNotFoundException {
    g.prepareToGeneration();

    PrintWriter out = new PrintWriter(target + "/Node.java");
    // out.println("import Lexer;\n");
    // out.println("package nodes;\n");
    out.println("class Node {");
    out.println("\tNode[] children;");
    out.println("\tpublic String text;");
    out.println("}");
    out.close();

    out = new PrintWriter(target + "/TerminalNode.java");
    out.println(
        "public class TerminalNode extends Node {\n\n"
            + "\tpublic TerminalNode(Lexer lx) {\n"
            + "\t\ttext = lx.getNext();\n"
            + "\t\tchildren = new Node[0];\n"
            + "\t}");
    out.println("}");
    out.close();

    out = new PrintWriter(target + "/EpsNode.java");
    out.println(
        "public class EpsNode extends Node {\n\n"
            + "\tpublic EpsNode() {\n"
            + "\t\ttext = \"EPS\";\n"
            + "\t\tchildren = new Node[0];\n"
            + "\t}");
    out.println("}");
    out.close();

    for (NonTerminal nt : g.nterms) {
      out = new PrintWriter(target + "/" + nt.getName() + "Node.java");
      out.println("import java.util.*;");
      out.println("class " + nt.getName() + "Node extends Node {");

      for (Attribute at : nt.atts) {
        out.println("\tpublic " + at.type + " " + at.name + ";");
      }
      out.println();

      out.println("\tpublic " + nt.getName() + "Node(Lexer lx) {");
      for (Rule r : nt.rules) {
        HashSet<String> good = new HashSet<String>();
        if (r.getChildCount() == 0) {
          good = nt.FOLLOW;
        } else {
          if (r.children.get(0).isTerminal()) {
            good.add(r.children.get(0).getName());
          } else {
            good.addAll(((NonTerminal) (r.children.get(0))).FIRST);
          }
        }
        out.print("\t\tif (");
        boolean first = true;
        if (r.getChildCount() == 0) {
          out.print("lx.nextIsEOF");
          first = false;
        }
        for (String t : good) {
          if (!first) out.print(" || ");
          first = false;
          out.print("lx.nextIs" + t + "");
        }
        out.println(") {");
        if (r.children.size() == 0) {
          out.println("\t\t\tchildren = new Node[1];");
          out.println("\t\t\tchildren[0] = new EpsNode();");
        } else {
          out.println("\t\t\tchildren = new Node[" + r.children.size() + "];");
          for (int i = 0; i < r.children.size(); i++) {
            Node n = r.children.get(i);
            if (n.isTerminal()) {
              out.println("\t\t\tchildren[" + i + "] = new TerminalNode(lx);");
            } else {
              out.println("\t\t\tchildren[" + i + "] = new " + n.getName() + "Node(lx);");
            }
          }
        }
        if (r.code != null) {
          String outCode = r.code;
          // System.err.println("--");
          // System.err.println(outCode);
          // System.err.println("@");
          for (int i = 0; i < r.getChildCount(); i++) {
            if (!r.children.get(i).isTerminal())
              outCode =
                  outCode.replaceAll(
                      "_" + i, "((" + r.children.get(i).getName() + "Node)(children[" + i + "]))");
            else outCode = outCode.replaceAll("_" + i, "children[" + i + "]");
          }
          // System.err.println(outCode);
          out.println(outCode);
        }
        out.println("\t\t\treturn;");
        out.println("\t\t}");
      }
      out.println("\t\tthrow new AssertionError(\"unexpected token :\" + lx.getNext());");
      out.println("\t}");

      out.println("}");
      out.close();
    }
  }