RunCC - A Java Runtime Compiler Compiler

RunCC is a new kind of parsergenerator that generates parsers and lexers at runtime. Source generation is only optional. It features simplicity, a standalone useable UNICODE enabled lexer, and a simple EBNF dialect for specifying syntaxes in a File. Although intended for small languages, it comes with Java and XML example parsers.

This package is open source, published under Lesser GNU Public License (LGPL).

This document applies to runcc 0.6. Old documentation is contained in old download archives.


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Author: Ritzberger Fritz, June 2004


Quick Start

A parser generator creates a parser from syntax rules. Rules are used to describe the inner structure of a text to analyze. When analyzed by the generated parser, the parts of the text can be processed by a semantic implementation. In short: a parser generator is a tool to create analyzers.

RunCC is written in Java. No additional libraries (except JRE) are required. It needs Java 2 collections (does not run on JDK 1.1 or older).
RunCC provides a bottom-up (LR) parser that can be SLR, LR or LALR. It provides a lexer that actually is a top-down (LL) parser and can read character (UNICODE) as well as byte input.
RunCC features simplicity and the absence of any cryptography except an EBNF dialect.
RunCC serializes built parsers and lexers to speed up the building process next time they are needed, so
RunCC provides source generation only as option. It can generate Java code for ParserTables, Syntax, and Semantic skeletons.
RunCC defines a clear separation of responsibilities: Syntax/Rule, Lexer, Parser, ParserTables, Semantic. No source fragments are possible within the syntax notation. Responsibilities are:
The syntax is written either embedded in Java as String arrays (representing rules), or within a separate file, using an EBNF dialect. No source fragments are possible within the syntax notation. This is done by Semantic implementations.

To understand those principles look at the following (classical) Calculator example, showing the elegance of ReflectSemantic.
Try it by typing
java -jar runcc.jar '(4+2.3) *(2 - -6) + 3*2'
or
java -cp runcc.jar fri.patterns.interpreter.parsergenerator.examples.Calculator '(4+2.3) *(2 - -6) + 3*2'
- i hope it will be 56.4 !

public class Calculator extends ReflectSemantic
{
    private static String [][] rules = {
        { "EXPRESSION",   "TERM" },
        { "EXPRESSION",   "EXPRESSION", "'+'", "TERM" },
        { "EXPRESSION",   "EXPRESSION", "'-'", "TERM" },
        { "TERM",   "FACTOR", },
        { "TERM",   "TERM", "'*'", "FACTOR" },
        { "TERM",   "TERM", "'/'", "FACTOR" },
        { "FACTOR",   "`number`", },
        { "FACTOR",   "'-'", "FACTOR" },
        { "FACTOR",   "'('", "EXPRESSION", "')'" },
        { Token.IGNORED,   "`whitespaces`" },
    };
   
    public Object EXPRESSION(Object TERM)    {
        return TERM;
    }
    public Object EXPRESSION(Object EXPRESSION, Object operator, Object TERM)    {
        if (operator.equals("+"))
            return new Double(((Double) EXPRESSION).doubleValue() + ((Double) TERM).doubleValue());
        return new Double(((Double) EXPRESSION).doubleValue() - ((Double) TERM).doubleValue());
    }
    public Object TERM(Object FACTOR)    {
        return FACTOR;
    }
    public Object TERM(Object TERM, Object operator, Object FACTOR)    {
        if (operator.equals("*"))
            return new Double(((Double) TERM).doubleValue() * ((Double) FACTOR).doubleValue());
        return new Double(((Double) TERM).doubleValue() / ((Double) FACTOR).doubleValue());
    }
    public Object FACTOR(Object number)    {
        return Double.valueOf((String) number);
    }
    public Object FACTOR(Object minus, Object FACTOR)    {
        return new Double( - ((Double) FACTOR).doubleValue() );
    }
    public Object FACTOR(Object leftParenthesis, Object EXPRESSION, Object rightParenthesis)    {
        return EXPRESSION;
    }


    public static void main(String [] args) throws Exception   {
        String input = args[0];   // define some arithmetic expressions on commandline
        Parser parser = new SerializedParser().get(rules, "Calculator");    // allocates a default lexer
        boolean ok = parser.parse(input, new Calculator());
        System.err.println("Parse return "+ok+", result: "+parser.getResult());
    }
}
You can find this sample in package fri/patterns/interpreter/parsergenerator/examples/Calculator.java.


Implementation Steps

Following are the steps to achieve your language implementation with RunCC.
  1. Define the target language syntax.

  2. Implement a Semantic

    The Semantic interface defines one method that receives all callbacks during parsing:

        doSemantic(Rule rule, List parseResult, List resultRanges)

    The parseResult will contain ...

    The resultRanges will contain the range(s) of the token texts within input text (e.g. for syntax-highlighting). The ranges List will be as long as parseResult list. It contains elements of type Token.Range.

    For convenience you can use ReflectSemantic. This class provides rule recognition by reflection (java.lang.reflect):

    When the method is not found, a fallback() method is called. This returns the token when it is just one, when the rule is left recursive and the first argument is instanceof List, the second argument is added to that List (can be used for automatic list aggregation). The fallback() is overrideable (protected).


    The implemented semantic must be passed to the Parser for processing:

    For a sample look at the HelloWorld example.


    For standalone lexers you need to use a


    implementation. The interface method receives every evaluated rule top-down. A ReflectLexerSemantic is provided in a sub-package, which works similar to ReflectSemantic for Parsers. The difference is that it can provide a Set of nonterminal Strings (left side of the rule) it wants to receive.



  3. Make the syntax available.

    Write a Java main class that contains the embedded syntax or uses SyntaxBuilder to read the EBNF file.

    When using Java-embedded rules (2D String array), the following will do it:

            String [][] rules = ...
        Syntax syntax = new Syntax(rules);

    When using an external EBNF file, the following will read it and convert it to a Syntax object (assuming the file is in same directory as the implementation):

        Reader syntaxInput = new InputStreamReader(MyLanguage.class.getResourceAsStream("MyLanguage.syntax"));
            SyntaxBuilder builder = new SyntaxBuilder(syntaxInput);
        Syntax syntax = builder.getSyntax();

    SyntaxBuilder     resolves all wildcard directives and alternative sentences within rules to plain rules. Doing that several new rules must be constructed. All nonterminals on the left sind of such artificial rules will start with "_".



  4. Load the lexer with input.

    Decide if this is a lexer problem or a parser is the better choice. Most likely you will try a lexer/parser combination first, but when there are too many shift/reduce conflicts, a standalone lexer might do it as well (the contained lexer can process even recursive rules, in fact it is a top-down parser).

    Assuming you defined a mixed parser and lexer syntax:

        SyntaxSeparation separation = new SyntaxSeparation(syntax);   // takes off TOKEN and IGNORED
        LexerBuilder builder = new LexerBuilder(separation.getLexerSyntax(), separation.getIgnoredSymbols());
        Lexer lexer = builder.getLexer();
        lexer.setInput("Very complicated text to analyze ...");

    Assuming you defined a pure lexer syntax (this is a complicated way, in fact you will use the lexer builder):

        SyntaxSeparation separation = new SyntaxSeparation(syntax);   // takes off TOKEN and IGNORED
        LexerBuilder builder = new LexerBuilder(separation.getLexerSyntax(), separation.getIgnoredSymbols());
        Lexer lexer = builder.getLexer();
        lexer.setTerminals(separation.getTokenSymbols());
        lexer.setInput("Very complicated text to analyze ...");


  5. Parse the input.

    The lexer was loaded with the input to parse, it represents the input of the parser.

    When using a parser-lexer combination, create the parser and parse:

        ParserTables parserTables = new LALRParserTables(separation.getParserSyntax());
        Parser parser = new Parser(parserTables);
        parser.parse(lexer, new MySemantic());    // here the missed setTerminals() happens

    When using a standalone lexer, you can lex using two different methods.

    1. You just want to receive tokens and output certain token texts (like in C-style-comment-strip example):

          Token token;
          do    {
              token = lexer.getNextToken(null);          // null: no hints what is expected
              if (token.symbol == null)
                  lexer.dump(System.err);
              else
              if (token.text != null)
                  System.out.write(token.text.toString());
          }
          while (token.symbol != null && Token.isEpsilon(token) == false);

    2. You want to parse top-down using the lexer (like in XML example), this evaluates the input (which means the Lexer returns false if there is more input to read!):

           LexerImpl lexer = (LexerImpl) builder.getLexer();  // need to cast to LexerImpl for lex() method
          boolean ok = lexer.lex(new MyLexerSemantic());


IMPORTANT:
When studying how to use RunCC, do not miss to read the examples. RunCC can be used in a lot of different ways for special purposes. The more complicated the problem, the deeper you will have to go into the framework. There are several examples packages, the most important is fri.patterns.interpreter.parsergenerator.examples.

 Using the builders

Parser builder

To speed up the building of parsers and to write some of those standard building sequences shorter you can use the builders in package fri/patterns/interpreter/parsergenerator/builders.

Lets look at "HelloWorld" example. Here is the first version of HelloWorld.java without builder (this simple Syntax can be done by simple SLRParserTables, normally you need not define the ParserTables class).

    private static final String [][] syntax =    {
        { "Start", "\"Hello\"", "\"World\"" },
        { Token.IGNORED, "`whitespaces`" },
    };
   
    public static void main(String [] args) throws Exception {
        // separate parser and lexer rules
         SyntaxSeparation separation = new SyntaxSeparation(new Syntax(syntax));
        // build the lexer from the lexer rules part
        LexerBuilder builder = new LexerBuilder(separation.getLexerSyntax(), separation.getIgnoredSymbols());
        Lexer lexer = builder.getLexer("\tHello \r\n\tWorld\n");    // the text to parse
        // build the parser from the parser rules part
        Parser parser = new Parser(new SLRParserTables(separation.getParserSyntax()));
        parser.parse(lexer, new PrintSemantic());
    }

To write this shorter and to speed up loading, a builder is used in HelloWorld2.java. This version lasts a little longer at the first time, but loads much faster at any further time.

    public static void main(String [] args) throws Exception {
        // build SLRParserTables, this is the simplest one, default is LALRParserTables
        Parser parser = new SerializedParser().get(SLRParserTables.class, syntax, "HelloWorld2");
        // generates "$HOME/.friware/parsers/HelloWorld2Parser.ser"
        parser.setInput("\tHello \r\n\tWorld\n");    // there was a default Lexer provided
        parser.parse(new PrintSemantic());
    }

Lexer builder

The following example shows how to build and use a Lexer.

    Reader syntaxInput = new InputStreamReader(XmlParser.class.getResourceAsStream("Xml.syntax"));
    Lexer lexer = new SerializedLexer().get(syntaxInput, "Xml");
    Reader parseInput = new FileReader(parseFile);
    lexer.setInput(parseInput);
    // scan the input with some LexerSemantic
     boolean ok = lexer.lex(new PrintLexerSemantic());

The PrintLexerSemantic implements LexerSemantic and communicates the rules it wants to receives by providing a Set of nonterminal Strings (that must match those written in the Syntax). See XmlLexer for a full example how to do this.

Lexer services

You can use the LexerImpl as top-down parser with a special semantic: LexerSemantic, or its utility implementation LexerReflectSemantic. You will receive the Rule and its ResultTree object in interface method, for LexerReflectSemantic you can simply implement the wanted callback methods, the Set of wanted nonterminal Strings will be provided automatically from those method names.

Example (assumed there is rule like "EncodingDecl ::= IsoString;" in lexing Syntax):
public class MyLexerSemantic extends LexerReflectSemantic
{
    private String encodingDecl;
    ...

    public void EncodingDecl(ResultTree resultTree)    {
        // process the result
        this.encodingDecl = resultTree.toString();    // you will get e.g. "ISO-8859-1"
    }
    ...
}

Lexer token listener

To receive every Token the Lexer has scanned, you can install a listener to the Lexer. This is for catching comments and spaces/newlines that are marked as ignored in the EBNF (will not reach the Parser). The start and end Token.Range is contained within the Token object. You can associate those ranges with the result ranges received in Semantic callbacks (where you have the ranges list of all parsed right side objects) to reconstruct the whole text. Token.Range implements hashCode(), equals() and Comparable to be manageable in some Map.

You install the listener by following code:
Lexer.TokenListener tokenListener = new Lexer.TokenListener()    {
    public void tokenReceived(Token token, boolean ignored)    {
        if (ignored)    {
            System.err.println("Having received ignored token: >"+token.getText()+"<");
        }
    }
};
parser.getLexer().addTokenListener(tokenListener);
parser.parse(new SomeSemantic());

Lexing without end-of-input

When you want to read some input that does not provide an end-of-input mark (EOF), but might contain valid text, you can use the getNextToken(LexerSemantic) method of LexerImpl:
LexerImpl lexer = (LexerImpl) builder.getLexer();  // need to cast to LexerImpl for getNextToken(LexerSemantic) method
Token token = getNextToken(someLexerSemantic);
if (token.symbol == null)
    System.out.println("error!");
System.out.println("Unread text starts at offset "+token.range.end.offset);


Three kinds of ParserTables

The provided bottom-up parser is a generic algorithm that runs with every syntax. It is driven by a ParserTables object that represents the syntax to be used on processing input. ParserTables contain the so-called GOTO-Table, the PARSE-ACTION table and some helper lists.

When implementing a language that uses a parser you must to decide which kind of parser tables you need. RunCC provides three kinds of parser tables:
The ParserTables implementations build on each other in an objectoriented way: SLRParserTables is the base, LRParserTables adds some functionality, and LALRParserTables is the most specialized derivation.

Optional source generation

When you want to increase the parser loading performance you can generate Java source code for following parts:
When launched without arguments, the SourceGenerator outputs the following message:

    SYNTAX: java fri.patterns.interpreter.parsergenerator.util.SourceGenerator [semantic|LALR|SLR|LR] file.grammar [file.syntax ...]

Predefined semantics

RunCC provides three Semantic implementations:

Syntax checker

RunCC provides a utility class to print diagnostics of an EBNF:
java fri.patterns.interpreter.parsergenerator.util.SyntaxChecker MySyntax.syntax
It detects

EBNF dialect

Following is the EBNF of the syntax definition language that you can use when not using embedded String array rules. It is described in its own syntax.
This file can be found in parsergenerator/syntax/builder/examples/SyntaxBuilder.syntax, but this is just a sample. The actual rules are embedded within SyntaxBuilderSemantic.java.

Mind that you should not use a starting '_' for nonterminals, as artificial rules do so (added when resolving parentheses and wildcards), and those will be optimized. It could happen that a rule with such a nonterminal will be removed before building the parser, which has the effect that the associated semantic never will be called.
syntax    ::=    rule +    // a syntax consists of one or more rules
    ;

set    ::=    `bnf_chardef` ".." `bnf_chardef`    // character set definition
    ;

intersectionstartunit    ::=    set | `identifier` | `ruleref`    // intersection of character sets
    ;
intersectionunit    ::=    `bnf_chardef` | `stringdef` | intersectionstartunit
    ;
intersection    ::=    intersectionstartunit ('-' intersectionunit)+
    ;

sequnit    ::=    intersection | intersectionunit | '(' unionseq ')'     // unit of a sequence
    ;
quantifiedsequnit    ::=    sequnit `quantifier` | sequnit    // unit can be quantified
    ;
sequence    ::=    quantifiedsequnit *    // sequence of units with significant order
    ;

unionseq    ::=    sequence ('|' sequence)*    // rule alternatives
    ;
rule    ::=    `identifier` "::=" unionseq ';'    // syntax rule
    ;

ignored ::= `comment` | `whitespaces`
    ;

EBNF syntax symbols


Following symbols can be used within this language (as described above):

Symbol
 Meaning
..
 For character set definitions, Java symbol is Token.UPTO, for example 'A' .. 'Z'
-
 For character set intersections (set constraints), Java symbol is Token.BUTNOT, for example `char` - `newline`
`
 The backquote (a UNIX shell reminiscence) is used to mark predefined lexer rules, these are implemented as String arrays within StandardLexerRules . Using `whitespaces` will import all rules describing whitespaces into the syntax. At the time there is no possibility to write your own importable lexer rules.
"
 Double quote is used to mark string literal like "for" or "if". It can also be used for characters: "c" is equal to 'c'.
'
 Single quote is used to mark characters or escape sequences like 'A' or '\n'. But you can NOT write 'string'!
10 Numbers express characters. The decimal number 10 would be \n. Stay within UNICODE range!
0xA
 A hexadecimal number, expressing the character \n.
012
 An octal number (starting with zero), expressing the character \n.
::=
 The original EBNF symbol to express "derives to".
|
 The pipe expresses "or", used for alternative rules: "a ::= b | c ;" means "a" derives to "b" or "c". Will be resolved to "a ::= b; a ::= c;"
;
 The rule (or rule alternation) terminator.
()
 Parenthesis are grouping markers. Such a group can be quantified by *+?, e.g. "(`char` - `newline`)*".
*
 Star marks a symbol or group that can repeat 0-n times ("optional list").
+
 Plus marks a symbol/group that can repeat 1-n times ("list").
?
 Question mark is used to express 0-1 occurences of a symbol/group ("optional").
/* ... */
 Comment marker, like in Java or C/C++.
//
Comment marker
#
 Comment marker


Package summary

This is a short introduction into the contents of every package contained in RunCC.

There are some other packages containing context-specific examples.

ParserTables sample dump

Dumping parser tables can be useful when studying the complicated ways of bottom-up parsing.
The follwing dump can be printed by writing the following Java source lines into a main class:
String [][] rules = ...;
ParserTables parserTables = new SLRParserTables(new Syntax(rules));
parserTables.dump(System.out);

The dump method lists rules, FIRST- and FOLLOW-sets, syntax nodes, and GOTO- and PARSE/ACTION-tables:


(Rule 0)  <START> : EXPR
(Rule 1)  EXPR : TERM
(Rule 2)  EXPR : EXPR '+' TERM
(Rule 3)  EXPR : EXPR '-' TERM
(Rule 4)  TERM : FAKT
(Rule 5)  TERM : TERM '*' FAKT
(Rule 6)  TERM : TERM '/' FAKT
(Rule 7)  FAKT : `NUMBER`
(Rule 8)  FAKT : '(' EXPR ')'

FIRST(EXPR) = [`NUMBER`, '(']
FIRST(FAKT) = [`NUMBER`, '(']
FIRST(<START>) = [`NUMBER`, '(']
FIRST(TERM) = [`NUMBER`, '(']

FOLLOW(FAKT) = [EOF, '+', '-', ')', '*', '/']
FOLLOW(EXPR) = [EOF, '+', '-', ')']
FOLLOW(<START>) = [EOF]
FOLLOW(TERM) = [EOF, '+', '-', ')', '*', '/']

State 0
  (Rule 0) <START> : .EXPR  -> State 2
  (Rule 1) EXPR : .TERM  -> State 1
  (Rule 2) EXPR : .EXPR '+' TERM  -> State 2
  (Rule 3) EXPR : .EXPR '-' TERM  -> State 2
  (Rule 4) TERM : .FAKT  -> State 4
  (Rule 5) TERM : .TERM '*' FAKT  -> State 1
  (Rule 6) TERM : .TERM '/' FAKT  -> State 1
  (Rule 7) FAKT : .`NUMBER`  -> State 5
  (Rule 8) FAKT : .'(' EXPR ')'  -> State 3

State 1
  (Rule 1) EXPR : TERM .
  (Rule 5) TERM : TERM .'*' FAKT  -> State 7
  (Rule 6) TERM : TERM .'/' FAKT  -> State 6

State 2
  (Rule 0) <START> : EXPR .
  (Rule 2) EXPR : EXPR .'+' TERM  -> State 9
  (Rule 3) EXPR : EXPR .'-' TERM  -> State 8

State 3
  (Rule 1) EXPR : .TERM  -> State 1
  (Rule 2) EXPR : .EXPR '+' TERM  -> State 10
  (Rule 3) EXPR : .EXPR '-' TERM  -> State 10
  (Rule 4) TERM : .FAKT  -> State 4
  (Rule 5) TERM : .TERM '*' FAKT  -> State 1
  (Rule 6) TERM : .TERM '/' FAKT  -> State 1
  (Rule 7) FAKT : .`NUMBER`  -> State 5
  (Rule 8) FAKT : '(' .EXPR ')'  -> State 10
  (Rule 8) FAKT : .'(' EXPR ')'  -> State 3

State 4
  (Rule 4) TERM : FAKT .

State 5
  (Rule 7) FAKT : `NUMBER` .

State 6
  (Rule 6) TERM : TERM '/' .FAKT  -> State 11
  (Rule 7) FAKT : .`NUMBER`  -> State 5
  (Rule 8) FAKT : .'(' EXPR ')'  -> State 3

State 7
  (Rule 5) TERM : TERM '*' .FAKT  -> State 12
  (Rule 7) FAKT : .`NUMBER`  -> State 5
  (Rule 8) FAKT : .'(' EXPR ')'  -> State 3

State 8
  (Rule 3) EXPR : EXPR '-' .TERM  -> State 13
  (Rule 4) TERM : .FAKT  -> State 4
  (Rule 5) TERM : .TERM '*' FAKT  -> State 13
  (Rule 6) TERM : .TERM '/' FAKT  -> State 13
  (Rule 7) FAKT : .`NUMBER`  -> State 5
  (Rule 8) FAKT : .'(' EXPR ')'  -> State 3

State 9
  (Rule 2) EXPR : EXPR '+' .TERM  -> State 14
  (Rule 4) TERM : .FAKT  -> State 4
  (Rule 5) TERM : .TERM '*' FAKT  -> State 14
  (Rule 6) TERM : .TERM '/' FAKT  -> State 14
  (Rule 7) FAKT : .`NUMBER`  -> State 5
  (Rule 8) FAKT : .'(' EXPR ')'  -> State 3

State 10
  (Rule 2) EXPR : EXPR .'+' TERM  -> State 9
  (Rule 3) EXPR : EXPR .'-' TERM  -> State 8
  (Rule 8) FAKT : '(' EXPR .')'  -> State 15

State 11
  (Rule 6) TERM : TERM '/' FAKT .

State 12
  (Rule 5) TERM : TERM '*' FAKT .

State 13
  (Rule 3) EXPR : EXPR '-' TERM .
  (Rule 5) TERM : TERM .'*' FAKT  -> State 7
  (Rule 6) TERM : TERM .'/' FAKT  -> State 6

State 14
  (Rule 2) EXPR : EXPR '+' TERM .
  (Rule 5) TERM : TERM .'*' FAKT  -> State 7
  (Rule 6) TERM : TERM .'/' FAKT  -> State 6

State 15
  (Rule 8) FAKT : '(' EXPR ')' .
 

GOTO TABLE
==========
      |  <START>    EXPR    TERM    FAKT     '+'     '-'     '*'     '/' `NUMBER     '('     ')'
________________________________________________________________________________________________
    0 |        -       2       1       4       -       -       -       -       5       3       -
    1 |        -       -       -       -       -       -       7       6       -       -       -
    2 |        -       -       -       -       9       8       -       -       -       -       -
    3 |        -      10       1       4       -       -       -       -       5       3       -
    4 |        -       -       -       -       -       -       -       -       -       -       -
    5 |        -       -       -       -       -       -       -       -       -       -       -
    6 |        -       -       -      11       -       -       -       -       5       3       -
    7 |        -       -       -      12       -       -       -       -       5       3       -
    8 |        -       -      13       4       -       -       -       -       5       3       -
    9 |        -       -      14       4       -       -       -       -       5       3       -
   10 |        -       -       -       -       9       8       -       -       -       -      15
   11 |        -       -       -       -       -       -       -       -       -       -       -
   12 |        -       -       -       -       -       -       -       -       -       -       -
   13 |        -       -       -       -       -       -       7       6       -       -       -
   14 |        -       -       -       -       -       -       7       6       -       -       -
   15 |        -       -       -       -       -       -       -       -       -       -       -

PARSE-ACTION TABLE
==================
      |      '+'     '-'     '*'     '/' `NUMBER     '('     ')'   <EOF>
________________________________________________________________________
    0 |        -       -       -       -      SH      SH       -       -
    1 |        1       1      SH      SH       -       -       1       1
    2 |       SH      SH       -       -       -       -       -      AC
    3 |        -       -       -       -      SH      SH       -       -
    4 |        4       4       4       4       -       -       4       4
    5 |        7       7       7       7       -       -       7       7
    6 |        -       -       -       -      SH      SH       -       -
    7 |        -       -       -       -      SH      SH       -       -
    8 |        -       -       -       -      SH      SH       -       -
    9 |        -       -       -       -      SH      SH       -       -
   10 |       SH      SH       -       -       -       -      SH       -
   11 |        6       6       6       6       -       -       6       6
   12 |        5       5       5       5       -       -       5       5
   13 |        3       3      SH      SH       -       -       3       3
   14 |        2       2      SH      SH       -       -       2       2
   15 |        8       8       8       8       -       -       8       8
 


Undone


Other parser generators

Thank god - nobody is alone!




Author: Ritzberger Fritz, June 2004