emitter.java

java语法解释器生成器

      println(" * This class is a scanner generated by ");
      println(" * <a href=\"http://www.jflex.de/\">JFlex</a> "+Main.version);
      println(" * on "+date+" from the specification file");    
      println(" * <tt>"+path+"</tt>");      
      println(" */");
    }   

    if ( scanner.isPublic ) print("public ");

    if ( scanner.isAbstract) print("abstract ");
   
    if ( scanner.isFinal ) print("final ");
    
    print("class ");
    print(scanner.className);
    
    if ( scanner.isExtending != null ) {
      print(" extends ");
      print(scanner.isExtending);
    }

    if ( scanner.isImplementing != null ) {
      print(" implements ");
      print(scanner.isImplementing);
    }   
    
    println(" {");
  }  

  /**
   * Try to find out if user code ends with a javadoc comment 
   * 
   * @param buffer   the user code
   * @return true    if it ends with a javadoc comment
   */
  public static boolean endsWithJavadoc(StringBuffer usercode) {
    String s = usercode.toString().trim();
        
    if (!s.endsWith("*/")) return false;
    
    // find beginning of javadoc comment   
    int i = s.lastIndexOf("/**");    
    if (i < 0) return false; 
       
    // javadoc comment shouldn't contain a comment end
    return s.substring(i,s.length()-2).indexOf("*/") < 0;
  }


  private void emitLexicalStates() {
    Enumeration stateNames = scanner.states.names();
    
    while ( stateNames.hasMoreElements() ) {
      String name = (String) stateNames.nextElement();
      
      int num = scanner.states.getNumber(name).intValue();

      println("  "+visibility+" static final int "+name+" = "+2*num+";");
    }

    // can't quite get rid of the indirection, even for non-bol lex states: 
    // their DFA states might be the same, but their EOF actions might be different
    // (see bug #1540228)
    println("");
    println("  /**");
    println("   * ZZ_LEXSTATE[l] is the state in the DFA for the lexical state l");
    println("   * ZZ_LEXSTATE[l+1] is the state in the DFA for the lexical state l");
    println("   *                  at the beginning of a line");
    println("   * l is of the form l = 2*k, k a non negative integer");
    println("   */");
    println("  private static final int ZZ_LEXSTATE[] = { ");
  
    int i, j = 0;
    print("    ");
    
    for (i = 0; i < 2*dfa.numLexStates-1; i++) {
      print( dfa.entryState[i], 2 );

      print(", ");

      if (++j >= 16) {
        println();
        print("    ");
        j = 0;
      }
    }
            
    println( dfa.entryState[i] );
    println("  };");
  }

  private void emitDynamicInit() {    
    int count = 0;
    int value = dfa.table[0][0];

    println("  /** ");
    println("   * The transition table of the DFA");
    println("   */");

    CountEmitter e = new CountEmitter("Trans");
    e.setValTranslation(+1); // allow vals in [-1, 0xFFFE]
    e.emitInit();
    
    for (int i = 0; i < dfa.numStates; i++) {
      if ( !rowKilled[i] ) {
        for (int c = 0; c < dfa.numInput; c++) {
          if ( !colKilled[c] ) {
            if (dfa.table[i][c] == value) {
              count++;
            } 
            else {
              e.emit(count, value);

              count = 1;
              value = dfa.table[i][c];              
            }
          }
        }
      }
    }

    e.emit(count, value);
    e.emitUnpack();
    
    println(e.toString());
  }


  private void emitCharMapInitFunction() {

    CharClasses cl = parser.getCharClasses();
    
    if ( cl.getMaxCharCode() < 256 ) return;

    println("");
    println("  /** ");
    println("   * Unpacks the compressed character translation table.");
    println("   *");
    println("   * @param packed   the packed character translation table");
    println("   * @return         the unpacked character translation table");
    println("   */");
    println("  private static char [] zzUnpackCMap(String packed) {");
    println("    char [] map = new char[0x10000];");
    println("    int i = 0;  /* index in packed string  */");
    println("    int j = 0;  /* index in unpacked array */");
    println("    while (i < "+2*intervals.length+") {");
    println("      int  count = packed.charAt(i++);");
    println("      char value = packed.charAt(i++);");
    println("      do map[j++] = value; while (--count > 0);");
    println("    }");
    println("    return map;");
    println("  }");
  }

  private void emitZZTrans() {    

    int i,c;
    int n = 0;
    
    println("  /** ");
    println("   * The transition table of the DFA");
    println("   */");
    println("  private static final int ZZ_TRANS [] = {"); 

    print("    ");
    for (i = 0; i < dfa.numStates; i++) {
      
      if ( !rowKilled[i] ) {        
        for (c = 0; c < dfa.numInput; c++) {          
          if ( !colKilled[c] ) {            
            if (n >= 10) {
              println();
              print("    ");
              n = 0;
            }
            print( dfa.table[i][c] );
            if (i != dfa.numStates-1 || c != dfa.numInput-1)
              print( ", ");
            n++;
          }
        }
      }
    }

    println();
    println("  };");
  }
  
  private void emitCharMapArrayUnPacked() {
  
    CharClasses cl = parser.getCharClasses();
    
    println("");
    println("  /** ");
    println("   * Translates characters to character classes");
    println("   */");
    println("  private static final char [] ZZ_CMAP = {");
  
    int n = 0;  // numbers of entries in current line    
    print("    ");
    
    int max =  cl.getMaxCharCode();
	
    // not very efficient, but good enough for <= 255 characters
    for (char c = 0; c <= max; c++) {
      print(colMap[cl.getClassCode(c)],2);
      
      if (c < max) {
        print(", ");        
        if ( ++n >= 16 ) { 
          println();
          print("    ");
          n = 0; 
        }
      }
    }
    
    println();
    println("  };");
    println();
  }

  private void emitCharMapArray() {       
    CharClasses cl = parser.getCharClasses();

    if ( cl.getMaxCharCode() < 256 ) {
      emitCharMapArrayUnPacked();
      return;
    }

    // ignores cl.getMaxCharCode(), emits all intervals instead

    intervals = cl.getIntervals();
    
    println("");
    println("  /** ");
    println("   * Translates characters to character classes");
    println("   */");
    println("  private static final String ZZ_CMAP_PACKED = ");
  
    int n = 0;  // numbers of entries in current line    
    print("    \"");
    
    int i = 0;
    int count, value;
    while ( i < intervals.length ) {
      count = intervals[i].end-intervals[i].start+1;
      value = colMap[intervals[i].charClass];

      // count could be >= 0x10000
      while (count > 0xFFFF) {
        printUC(0xFFFF);
        printUC(value);
        count -= 0xFFFF;
        n++;       
      }
        
      printUC(count);
      printUC(value);

      if (i < intervals.length-1) {
        if ( ++n >= 10 ) { 
          println("\"+");
          print("    \"");
          n = 0;
        }
      }

      i++;
    }
      
    println("\";");
    println();

    println("  /** ");
    println("   * Translates characters to character classes");
    println("   */");
    println("  private static final char [] ZZ_CMAP = zzUnpackCMap(ZZ_CMAP_PACKED);");
    println();
  }


  /**
   * Print number as octal/unicode escaped string character.
   * 
   * @param c   the value to print
   * @prec  0 <= c <= 0xFFFF 
   */
  private void printUC(int c) {
    if (c > 255) {
      out.print("\\u");
      if (c < 0x1000) out.print("0");
      out.print(Integer.toHexString(c));
    }
    else {
      out.print("\\");
      out.print(Integer.toOctalString(c));
    }    
  }


  private void emitRowMapArray() {
    println("");
    println("  /** ");
    println("   * Translates a state to a row index in the transition table");
    println("   */");
    
    HiLowEmitter e = new HiLowEmitter("RowMap");
    e.emitInit();
    for (int i = 0; i < dfa.numStates; i++) {
      e.emit(rowMap[i]*numCols);
    }    
    e.emitUnpack();
    println(e.toString());
  }


  private void emitAttributes() {
    println("  /**");
    println("   * ZZ_ATTRIBUTE[aState] contains the attributes of state <code>aState</code>");
    println("   */");
    
    CountEmitter e = new CountEmitter("Attribute");    
    e.emitInit();
    
    int count = 1;
    int value = 0; 
    if ( dfa.isFinal[0]    ) value = FINAL;
    if ( !isTransition[0]  ) value|= NOLOOK;
       
    for (int i = 1;  i < dfa.numStates; i++) {      
      int attribute = 0;      
      if ( dfa.isFinal[i]    ) attribute = FINAL;
      if ( !isTransition[i]  ) attribute|= NOLOOK;

      if (value == attribute) {
        count++;
      }
      else {        
        e.emit(count, value);
        count = 1;
        value = attribute;
      }
    }
    
    e.emit(count, value);    
    e.emitUnpack();
    
    println(e.toString());
  }


  private void emitClassCode() {
    if ( scanner.eofCode != null ) {
      println("  /** denotes if the user-EOF-code has already been executed */");
      println("  private boolean zzEOFDone;");
      println("");
    }
    
    if ( scanner.classCode != null ) {
      println("  /* user code: */");
      println(scanner.classCode);
    }
  }

  private void emitConstructorDecl() {
    emitConstructorDecl(true);
    
    if ((scanner.standalone || scanner.debugOption) && 
        scanner.ctorArgs.size() > 0) {
      Out.warning(ErrorMessages.get(ErrorMessages.CTOR_DEBUG));
      println();
      emitConstructorDecl(false);
    }
  }
  
  private void emitConstructorDecl(boolean printCtorArgs) {
 
    String warn = 
        "// WARNING: this is a default constructor for " +
        "debug/standalone only. Has no custom parameters or init code.";
    
    if (!printCtorArgs) println(warn); 
    
    print("  ");

    if ( scanner.isPublic ) print("public ");   
    print( getBaseName(scanner.className) );      
    print("(java.io.Reader in");
    if (printCtorArgs) emitCtorArgs();
    print(")");
    
    if ( scanner.initThrow != null && printCtorArgs) {
      print(" throws ");
      print( scanner.initThrow );
    }
    
    println(" {");

    if ( scanner.initCode != null && printCtorArgs) {
      print("  ");
      print( scanner.initCode );
    }

    println("    this.zzReader = in;");

    println("  }");
    println();