A Quick Introduction to SDF

by Joost Visser and Jeroen Scheerder

Abstract

This paper is intended for first time users. It contains motivation for using SDF with Generalized LR parsing and a step-by-step guided tour along the main features. The paper answers some some basic questions about SDF and gives a step-by-step recipe for developing SDF grammars. It even touches on the issue of writing Island Grammars in SDF.

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The SDF open-source software license (BSD)

Copyright (c) 2002-2007, CWI All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of CWI nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The source code of SDF is split in several components. Each component implements the same build interface, and adheres to certain coding standards.

Programming environment

• This document describes how to get the SDF source from subversion and how to build all components in the right order.
• This document describes how the SDF team uses version management.

by MarkVanDenBrand, JeroenScheerder^?, JurgenVinju and EelcoVisser. Disambiguation filters for scannerless generalized LR parsers. In N. Horspool, editor, Compiler Construction (Transform.CC'02), volume 2304 of Lecture Notes in Computer Science, pages 143--158, Grenoble, France, April 2002. Springer-Verlag.

Abstract

In this paper we present the fusion of generalized LR parsing and scannerless parsing. This combination supports syntax definitions in which all aspects (lexical and context-free) of the syntax of a language are defined explicitly in one formalism. Furthermore, there are no restrictions on the class of grammars, thus allowing a natural syntax tree structure. Ambiguities that arise through the use of unrestricted grammars are handled by explicit disambiguation constructs, instead of implicit defaults that are taken by traditional scanner and parser generators. Hence, a syntax definition becomes a full declarative description of a language. Disambiguation constructs can be interpreted as filters on parse forests. Scannerless generalized LR parsing is a viable technique that has been applied in various industrial and academic projects.

Technical report

• http://www.cs.uu.nl/~visser/ftp/BSVV02.pdf

Review

The following is an excerpt from a anonymous referee report:

This paper, "Disambiguation Filters for Scannerless Generalized LR Parsers," is about a systematic way of dealing with the problem of parsing with ambiguous grammars.

I thought this paper was wonderful. Sure it has some flaws, but I think it and all the SGLR papers should be required reading by all faculty who teach compilers and all graduate students who will someday teach compilers. Why? Because SGLR represents so many advantages over the lex+yacc or hand-coded lexer+parser models that the only compelling reason that I can think of to not teach SGLR is, as Homer Simpson would say, "It's a good idea, but it's a new idea, and, therefore, I fear it and must reject it." (OK, it does have one disadvantage that is serious, speed, but that's not enough of a concern to eliminate it from all compiler jobs.)

So, what's SGLR? It's a system of handling all lexical and parsing concerns within a unified Generalized LR parser. This unified system has advantages galore, which are well-described in the paper. Because it uses GLR parsing technology it allows ambiguous grammars. This paper describes 4 mechanisms that allow for declarative disambiguation of the resulting parses. All four are well described and carefully analyzed.

---

CategoryPaper

There are a number of features for disambiguation in SDF2.

Associativity

Associativity declarations are used to solve ambiguities of an operator with respect to itself. For example, the production

Exp "+" Exp -> Exp {left}

is annotated with the attribute 'left' which entails that addition is left associative with respect to itself, i.e., a + b + c should be read as (a + b) + c.

Priorities

Priorities can be used to solve ambiguities between operators. For example, the priority declaration

Exp "*" Exp -> Exp > Exp "+" Exp -> Exp

declares multiplication to have higher priority than addition.

Reject Productions

Reject productions are used to exclude some phrases from a sort. The standard application is the exclusion of keywords from lexical sorts. For example, the reject production

"if" -> Id {reject}

excludes 'if' as an identifier.

Restrictions

Follow restrictions are used to declare that some sort cannot be followed by some characters. For instance, the restriction

Id -/- [a-z]

declares that phrases of the sort Id cannot be followed by lower case letters.

Other Disambiguation Methods

• avoid
• prefer

Introduction

A parsing algorithm that maintains multiple LR parsing states in parallel.

From Object Oriented Tree Traversal With JJForester :

GeneralizedLR parsing removes the restriction to a non-ambiguous subclass of the context-free grammars, such as the LR(k) class. This allows a maximally natural expression of the intended syntax; no more need for `bending over backwards' to encode the intended grammar in a restricted subclass. Furthermore, generalized parsing leads to better modularity and allows `as-is' syntax reuse.

Implementations

Implementations of GLR using a separate scanner

• ElkHound is GLR parser generator
• Bison includes an GLR parser.
• PyGgy A Python parser generator that generates SLR tables for a GLR parsing engine.

Implementations of Scannerless Generalized LR

• SGLR is a Scannerless Generalized LR parser
• DParser is Scannerless Generalized LR parser generator.

The maintainers of Elkhound maintain a list of implementations as well.

Description

The Grammar Base is a collection of Sdf syntax definitions. Its purpose is to:

1. provide syntax definitions for a wide range of existing languages so that at least the parsing side of implementing language processing tools for these languages becomes easier;
2. provide examples of the usage of SDF;
3. promote the use of SDF; and
4. provide real-life data for testing and benchmarking the implementation of SDF.

Grammars

A list of grammars in the Grammar Base is available online at:

• http://www.cwi.nl/~mdejonge/grammar-base/

If you have a syntax definition for a language that is not listed there and that you would like to contribute, or if you have a request for a particular language, please contact the Grammar Base maintainers^?.

Grammar Management

• Grammar Maturity Levels^?
• Grammar Version Numbers^?
• Grammar Benchmarks^?
• Grammar Testing

If you would like to contribute to the GrammarBase, take a look at the GrammarBaseTaskList^?, and read about AddingAGrammarToGB^?.

Tools

• ParseUnit is a tool for unit-testing SDF syntax definitions

LeonMoonen^? asked me what the difference is between lexical and context-free FollowRestrictions^? in SDF2. Here follows my response. (Unfortunately it is in dutch.) -- EelcoVisser - 29 Mar 2001

> Ik ben een beetje in verwarring geraakt over lexicale versus context-vrije
> restricties in SDF(2).
> 
> - is er wel verschil?
> - zo ja, wanneer lexicaal en wanneer context-vrij gebruiken?

Het verschil is:

  lexical restrictions 
     A -/- cc1
  context-free restrictions
     B -/- cc2

wordt genormaliseerd naar

   restrictions
     <A-LEX> -/- cc1
     <B-CF> -/- cc2

Zie pagina 207 proefschrift

> "vroeger" dacht ik dat een lexicale restrictie (denk aan "longest match")
> betekende dat er *geen* optionele layouit tussen soort en de
> restricted chars mochten staan. Bij context-vrije zou dat dan wel mogen. 
> Dat blijkt niet waar te zijn (experimenteel vastgesteld). 

Nee, een restrictie S -/- cc (zie boven voor verschil tussen lex en cf)
betekent dat characters uit cc die niet mogen voorkomen achter een boom van
soort S. De implementatie van restricties (waarbij een enkele character set
gegeven is) wordt gegeven op pagina 47 van proefschrift; regel (Fo4). Een
restrictie heeft tot gevolg dat de follow set van soort S beperkt wordt. Dit
sluit een reductie van een S boom uit in het geval er een karacter uit cc
volgt.

> Helaas ga je in jouw proefschrift niet in op context-vrije restricties 
> (wel op lexicale) en uit de specs kan ik niet direct een verschil 
> afleiden (behalve op welke soorten ze toegepast worden).

Er staan inderdaad geen voorbeelden in van context-vrije restricties, maar de
semantiek is dus hetzelfde als die van lexicale. (Pagina's 207 en 47)

> De reden dat ik meer wil weten is dat ik bezig ben met island grammars 
> en in sommige gevallen een ambiguiteit op kan lossen met een 
> context-vrije restrictie op een verder lexicaal gedefinieerde soort 
> ([a-z]+ -> Water). 

Als je het voorbeeld wat uitgebreider beschrijft kan ik je misschien helpen.

* The SDF users list (brand new) is for all matters concerning SDF usage * subscribe * unsubscribe * mail your question, idea, issue

* The SDF developers list is reserved for committers to the SDF project * subscribe * unsubscribe * mail your question or discussion

These are older releases of SDF; if you need something even older contact mailto:users@syntax-definition.org^? * SDF 2.6 source bundle * SDF 2.5.1 source bundle * SDF2 Bundle 2.3.3 * Latest unstable sdf2-bundle 2.3.3 * SDF2 Bundle 2.3.2 * SDF2 Bundle 2.3.1 * SDF2 Bundle 2.3 * SDF2 Bundle 2.2 * SDF2 Bundle 2.1 * SDF2 Bundle 2.0.1 * SDF2 Bundle 1.6

Description

The package PGEN (for Parsetable Generator) contains tools for generating parse tables.

Tools

• sdf2table

Links

The official homepage of PGEN:

• http://www.cwi.nl/projects/MetaEnv/pgen/

See also

• SDF Web
• SGLR Parsetable Format

• AQuickIntroductionToSDF. Joost Visser and Jeroen Scheerder. 2000

• SyntaxDefinitionForLanguagePrototyping^?. Eelco Visser. PhD^? Thesis, University of Amsterdam. September, 1997.

• A Family of Syntax Definition Formalisms. Eelco Visser. In Mark van den Brand et al., editors. ASF+SDF95. A Workshop on Generating Tools from Algebraic Specifications. Technical Report P9504, Programming Research Group, University of Amsterdam, May 1995. pages 89-126. An extended and improved version of the paper appeared as Technical Report P9706, Programming Research Group, University of Amsterdam, July 1997.

• A case study in optimizing parsing schemata by disambiguation filters. Eelco Visser. In International Workshop on Parsing Technology (IWPT97), Boston, USA, September 1997.

• Character classes. Eelco Visser. Technical Report P9708, Programming Research Group, University of Amsterdam, August 1997.

• Scannerless Generalized-LR Parsing. Eelco Visser. July, 1997. Technical Report P9707, Programming Research Group, University of Amsterdam.

• From Context-Free Grammars with Priorities to Character Class Grammars. Eelco Visser. In Liber Amicorum Paul Klint. CWI, Amsterdam, November 1997. Also appeared as Technical Report P9717, Programming Research Group, University of Amsterdam, October 1997.

• Using Filters for the Disambiguation of Context-free Grammars. Paul Klint and Eelco Visser. In G. Pighizzini and P. San Pietro, editors, Proceedings ASMICS Workshop on Parsing Theory, pages 1-20, Milano, Italy, October 1994. Tech. Rep. 126-1994, Dipartimento di Scienze dell Informazione, Università di Milano. Also appeared as Technical Report P9426, Programming Research Group, University of Amsterdam, December 1994. (Recent version in PhD^? thesis)

Proposed Changes

A summary of changes from SDf.2.1 to SDF.2.2 :

• The syntax of Tools.ATerms will be used for SDF attributes for example: A -> B {left} B -> C {aap(noot,mies)}

• SDF layout is defined in a separate module and imported at the top. This allows other modules to be reused without inheriting the SDF layout and comment conventions.

• Tools.ATerm and SDF unquoted literals are distinguished using the sort UQSdfLiteral^?.

• The "definition" keyword is removed. An SDF definition is just a sequence of SDF modules: Module* -> Definition

• The following file extensions will be used for SDF modules and definitions:
  • .sdf for SDF modules
  • .def for SDF definitions

• The SDF grammar will contain constructor annotations which define the abstract syntax of SDF

• Three new constructors are introduced in AsFix:
  • qlit to represent quoted literals
  • uqlit to represent unquoted literals
  • flatlex to represent flattened lexicals

• The production sorts Symbols -> Grammar has been replaced bu sorts Sorts -> Grammar

Unresolved Issues

• Do we need directly visible kernel syntax?

• Are there convincing examples of kernel syntax?
• Why can these not be handled by lexical syntax?

• How do the sorts in kernel syntax and other sections relate?

• Do we need aliases?

• Why Symbols in parameter list following module name?

• Keyword "Set" should be "set"

• Do we need the "(" Symbol "=>" Symbol ")" syntax?

• Why are the lookaheads "" {Lookahead ","}* "^?" visible? Should belong to kernel syntax.

• How to add GrammarAnnotations^??

(note: this is not an official release plan and probably quite out of date. Please update if some info is incorrect!)

Below is a list of considerations for the next generation (version 3) of the Syntax Definition Formalism SDF:

• An improved mechanism to deal with multiple types of layout is desirable
  • Idea: No longer specify layout using the sort LAYOUT but rather make layout a parameter of context-free syntax sections context-free syntax (C-Layout) foo bar -> C context-free syntax (Sdf-Layout) hello world -> Sdf

• In the current version of SDF the priority of alternatives is strange and differs from alternative syntax definition formalisms. A B | C D is grouped as A (B|C) D instead of (A B) | (C D). Can SDF be redesigned to improve this?
  • Idea: use explicit sequence operator: A . B | C . D

• What are the top sorts of a grammar? Currently all declared sorts automatically become top sorts. This behavior allows sentences over a sub part of a language to be accepted by the parser. Parsing over a part of a language is required during development of a grammar and corresponding tooling. In general however, the number of top sorts needs to be restricted in order for the parser to only accept sentences that really belong to a language.
  • Idea: Add "top sorts" section to SDF
  • Idea: Adapt the parser generator to support multiple start states which are independent of the declared top sorts.

• What naming scheme to use to specify and locate Sdf modules?
  • Idea: use Java's Internet-wide unique package naming scheme. imports nl.cwi.gb.sdf.* nl.cwi.gb.aterms.*

• What flattening methods of lexicals are required?
  • Idea: flattening with structure preservation. This approach would for instance preserve the lexical structure of URL's (["http:","//", "www.cwi.nl", "/"]) * Idea: flattening without structure preservation. For example: "http://www.cwi.nl/"

• To decrease the dependency of tools on the abstract syntax format of Sdf and to ease manipulation of Sdf parse trees, an AsFix API is required. This API should provide efficient access functions to AsFix terms and preferably should be generated from the Sdf syntax.

• Do we really need hidden and exported grammars?

SDF2 is a rich formalism for the definition of the syntax of all kinds of computer languages. This page explores the possibilities of the formalism by means of a number of fragments of syntax definitions from the SDF2 GrammarBase. In particular, the language is contrasted with traditional formalisms that use a separate scanner to deal with lexical syntax.

(When editing this page, uncheck the ConvertSpacesToTabs^? checkbox to avoid spoiling the layout of the examples.)

Context-free Syntax Definition

expression grammar

Disambiguating Expressions

Lexical Syntax Definition

idenitifiers, layout

Regular Expressions

Overloading Delimiters

BibTeX^? is a language for the describtion of bibliographical information such as articles and books. For example, the following entry describes a PhD^? thesis.

 @PhdThesis{Vis97.thesis,
   author = {Visser, Eelco},
   title  = {Syntax Definition for Language Prototyping},
   year   = {1997},
   month  = {September},
   school = {University of Amsterdam},
   URL    = { http://www.cs.uu.nl/~visser/thesis/ }
 }

In the syntax of BibTeX^? entries the symbol { has two meanings: (1) indicating the start of the list of fields and (2) indicating the start of a field body. The second kind of use requires a lexical treatment since the body of a field consists of an arbitrary list of characters until the closing } is found. In an approach where scanner and parser are separated it is not possible for the scanner to know which kind of { is encountered. Furthermore, a field body can contain nested occurences of { and }, which should only occur in matching pairs. In

Finally, the treatment of whitespace is different between entries, between the fields of an entry and inside the body of a field.

  context-free syntax
    C {Entry C}* C                  -> Entries 
    "@" EName "{" Key "," 
                  {Field ","}* ","? 
              "}"                   -> Entry 
    Name "=" Value                  -> Field
    "{" ValWords "}"                -> Value
    (ValWord | ("{" ValWords "}"))* -> ValWords
  lexical syntax
    ~[\{\}\ \t\n]+  -> ValWord
  lexical restrictions
    ValWord   -/- ~[\{\}\ \t\n]

The complete syntax definition for BibTeX^? (that also treats double quotes in field bodies correctly) can be found at

http://www.cwi.nl/~mdejonge/grammar-base/bibtex.0/index.html

Solving Lexical Ambiguities

Longest Match

follow restrictions

Reserved Words

in a normal scanner generator like LEX

when combining languages we want to have separate sets of reserved words;

a COBOL reserved word should not be used as a COBOL identifier, but might be quite usable as a SQL identifier

Ignoring Whitespace in Lexicals

In Fortran whitespace inside lexicals is not significant. This can be accomodated in Trash.SDFII by using context-free syntax to define lexicals.

Dividing a Syntax Definition into Modules

reuse of pieces of syntax

renaming

Combining Languages

COBOL is a language for manipulating business information represented by means of lists of records. COBOL programs are often mixed with fragments from other languages. For example, SQL queries can be embedded to access a database and CICS programs are used for process control. It is desirable to describe the syntax of each of the language separately and combine these descriptions as needed.

In a traditional syntax definition formalism this is not possible: (1) The grammars restrictions such LL or LALR on which the context-free syntax is based are not closed under composition. (2) the regular grammars on which the definition of the lexical syntax are based are not closed under composition either.

In practice, this translates to the following: A scanner does not consider the context in determining the sort of a token. Therefore, normal scanners cannot deal with

(LEX provides a workaround by means of modes.)

In Trash.SDFII the syntax of the composing languages can be described in separate modules and combined at will. For example, consider the following fragments from a syntax definition for COBOL. (Note that the actual combined syntax definition for COBOL, CICS and SQL combined consists of 1600 LOC divided into 38 modules.)

Module ID defines the syntax of identifiers. The 

 module ID
   lexical syntax
     [0-9]* [A-Z]                                          -> Lex-Id
     [0-9]* [A-Z] [A-Za-z0-9\-]* [A-Za-z0-9]               -> Lex-Id
     [0-9]+ [\-] [0-9\-]* [A-Z] [A-Za-z0-9\-]* [A-Za-z0-9] -> Lex-Id
   context-free syntax
     Lex-Id -> Id 
   lexical restrictions
     Lex-Id -/- [A-Za-z0-9\-]

Module COBOL defines the syntax of COBOL programs. The actual syntax definition for cobol consists of 36 modules. Here only the productions relevant for the example are shown. Note that the syntax of Picture overlaps with the syntax for Id. This overlap is disambiguated by context.

 module COBOL
   imports ID %% ...
   lexical syntax
     [0-9XxAa\(\)pZzVvSszBCRD\/\,\$\+\-\*\:]+ -> Picture
   context-free syntax
     Ident-div Env-div Data-div Proc-div            -> Program
     "DATA" "DIVISION" "." File-sec Ws-sec Link-sec -> Data-div
     "FILE" "SECTION" "." File-desc*                -> File-sec
     "FD" Id Fd-item* "." Data-desc*                -> File-desc
     Dd-header Dd-body*                             -> Data-desc

Module SQL defines the syntax for SQL queries. Queries are embedded into COBOL programs by means of the keywords EXEC SQL ... END-EXEC.

 module SQL
   lexical syntax
     [A-Z0-9\-\_\.\:]+ -> Sql-id
   context-free syntax
     "SELECT" Distinct Select-list From-into Where Order-by -> Select
     Select                                                 -> Sql-item
     "EXEC" "SQL" Sql-item+ "END-EXEC" "."                  -> Data-desc
     "EXEC" "SQL" Sql-item+ "END-EXEC"                      -> Stat

Module CICS defines the syntax of CICS commands and their embedding in COBOL programs. Note that a command can have a reference to an A-exp, which is a COBOL expression.

 module CICS
   imports PROGRAM
   lexical syntax
     [A-Z]+ -> Cics-kw
   context-free syntax
     Stat* "EXEC" "CICS" Cics-command Cics-opt* "." -> Sentence
     "EXEC" "CICS" Cics-command Cics-opt* "END-EXEC" -> Stat
            
     Cics-kw                  -> Cics-opt
     Cics-kw "(" Cics-arg ")" -> Cics-opt
     A-exp                    -> Cics-arg
     Str                      -> Cics-arg
     "ADDRESS" "OF" A-exp     -> Cics-arg
     "LENGTH" "OF" A-exp      -> Cics-arg
     "ABEND"                  -> Cics-command
     %% etc.

Description

SGLR, Scannerless Generalized LR Parser, is an implementation of Tomita's Generalized LR algorithm with extensions for scannerless parsing. The SGLR package contains the tool sglr, which is a generic parser. The sglr parser interprets parse tables generated by the parse table generator from an SDF2 syntax definition. The parser outputs parse trees or parse forests if there is more than one possible parse tree.

Links

The official homepage of SGLR: * http://www.meta-environment.org

See also

* SDF Publications * SGLR parse table format

From the report Scannerless Generalized LR Parsing:

Scannerless parsing is a parsing technique in which lexical and context-free syntax are integrated into one grammar and are all handled by a single context-free analysis phase. This approach has a number of advantages including discarding of the scanner and lexical disambiguation by means of the context in which a lexical token occurs.

Implementations

• SGLR is a Scannerless Generalized LR parser
• DParser is Scannerless Generalized LR parser generator.

SDF2 Bundle 1.6

Contents

sdf2-bundle 1.6 consists of: * asc-support-1.6 * asf-support-1.0 * sdf-support-1.0 * pt-support-0.11 * sglr-3.9 * toolbuslib-0.4 * pgen-1.6

Download

See the installation instructions if you are not familiar with the standard installation procedure of tarballs or RPMs.

Source tar.gz

* aterm-2.0 * sdf2-bundle-1.6

Source RPM

* aterm-2.0 * sdf2-bundle-1.6

Redhat Linux RPM

Redhat 8.0: * aterm-2.0 * sdf2-bundle-1.6

Redhat 9.0: * aterm-2.0 * sdf2-bundle-1.6

SuSE Linux RPM

SuSE 8.2: * aterm-2.0 * sdf2-bundle-1.6

SDF2 Bundle 2.0.1

Contents

sdf2-bundle 2.0.1 consists of: * asc-support-1.8 * asf-support-1.2 * sdf-support-2.0 * pt-support-1.0 * sglr-3.10.2 * toolbuslib-0.5.1 * pgen-2.0

Download

See the installation instructions if you are not familiar with the standard installation procedure of tarballs or RPMs.

Source tar.gz

* aterm-2.0.5 * sdf2-bundle-2.0.1

Source RPM

* aterm-2.0.5 * sdf2-bundle-2.0.1

Redhat Linux RPM

Redhat 8.0: * aterm-2.0.5 * sdf2-bundle-2.0.1

Redhat 9.0: * aterm-2.0.5 * sdf2-bundle-2.0.1

SuSE Linux RPM

SuSE 8.2: * aterm-2.0.5 * sdf2-bundle-2.0.1

SDF2 Bundle 2.1

Contents

sdf2-bundle 2.1 consists of: * asc-support-1.9 * asf-library-1.0 * asf-support-1.3 * error-support-0.1.1 * pgen-2.1 * pt-support-1.1 * sdf-support-2.1 * sglr-3.11 * toolbuslib-0.6

Download

See the installation instructions if you are not familiar with the standard installation procedure of tarballs or RPMs.

Source tar.gz

* aterm-2.1 * sdf2-bundle-2.1

Source RPM

* aterm-2.1 * sdf2-bundle-2.1

Redhat Linux RPM

Redhat 8.0: * aterm-2.1 * sdf2-bundle-2.1

Redhat 9.0: * aterm-2.1 * sdf2-bundle-2.1

SuSE Linux RPM

SuSE 8.2: * aterm-2.1 * sdf2-bundle-2.1

Released July 04, 2004.

The SDF2 Bundle is an easy to install collection of packages that implement the modular SDF syntax definition formalism.

Contents

SDF2 Bundle 2.2 consists of:

* sglr-3.12 * pgen-2.2 * asf-library-1.1 * asc-support-2.0 * asf-support-1.4 * sdf-support-2.1.1 * pt-support-1.2 * toolbuslib-0.6 * error-support-0.1.1

SDF2 Bundle 2.2 requires: * ATerm Library 2.2

Download

See the installation instructions if you are not familiar with the standard installation procedure of tarballs or RPMs.

Source tar.gz

* aterm-2.2 * sdf2-bundle-2.2

Source RPM

* aterm-2.2 * sdf2-bundle-2.2

Redhat Linux RPM

Redhat 8.0: * aterm-2.2 * sdf2-bundle-2.2

Redhat 9.0: * aterm-2.2 * sdf2-bundle-2.2

SuSE Linux RPM

SuSE 8.2: * aterm-2.2 * sdf2-bundle-2.2

SuSE 9.0: * aterm-2.2 * sdf2-bundle-2.2

Fedora Core RPM

Fedora Core 2: * aterm-2.2 * sdf2-bundle-2.2

Fedora Core 3: * aterm-2.2 * sdf2-bundle-2.2

Mac OS X binaries

* aterm-2.2 * sdf2-bundle-2.2

* The *-macosx.tar.gz files contain a file readme.txt with installation instructions.

Microsoft Windows Cygwin binaries * aterm-2.2 * sdf2-bundle-2.2

* The *-cygwin.tar.gz files contain a file readme.txt with installation instructions.

Released January 10, 2005.

Download

See the installation instructions if you are not familiar with the standard installation procedure of tarballs or RPMs.

Source tar.gz

* aterm-2.3.1 * sdf2-bundle-2.3^?

Source RPM

* aterm-2.3.1^? * sdf2-bundle-2.3^?

Redhat Linux RPM

Redhat 9.0: * aterm-2.3.1^? * sdf2-bundle-2.3^?

SuSE Linux RPM

SuSE 9.0: * aterm-2.3.1^? * sdf2-bundle-2.3^?

Fedora Core RPM

Fedora Core 2: * aterm-2.3.1^? * sdf2-bundle-2.3^?

Fedora Core 3: * aterm-2.3.1^? * sdf2-bundle-2.3^?

Microsoft Windows Cygwin binaries

* aterm-2.3.1^? * sdf2-bundle-2.3^?

* The *-cygwin.tar.gz files contain a file readme.txt with installation instructions.

Mac OS X binaries

* aterm-2.3.1^? * sdf2-bundle-2.3^?

* The *-macosx.tar.gz files contain a file readme.txt with installation instructions.

License

The SDF2 Bundle is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (GNU LGPL) as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details

Contents

SDF2 Bundle 2.3 consists of: * asc-support-2.2 * asf-library-1.2.1 * asf-support-1.4.2 * error-support-1.0.1 * pgen-2005-01-10 * pt-support-1.4 * sdf-support-2.1.3 * sglr-3.14 * toolbuslib-0.7.1 * tide-support-1.0

SDF2 Bundle 2.3 requires: * ATerm Library 2.3.1

News

This is mainly a maintenance release, fixing a number of bugs. However, a number of important features have been added.

* Fixed a bug in obtaining a parse table when restoring brackets with a grammar without start symbols.

* Fixed implosion of alternative literals. "-" | "+" becomes alt(1,[]) or alt(2,[]) because a literal does not have a representation in an imploded tree. This fixes a core dump

* The efficiency of the syntax checker was improved drastically. This reduces parsetable generation times.

* A new commandline tool: filterPT. It filters parse forests based on some command line arguments. Currently, we have one filter to find trees with a maximum or minumum number of occurrences of a certain non-terminal. It is used to implement filters for island grammars.

* A new small package: tide-support. Contains a library for developing new TIDE debugging adapters.

(News selected from Meta-Environment 1.5.2 and 1.5.3 news)

Released August 17, 2005.

Download

See the installation instructions if you are not familiar with the standard installation procedure of tarballs or RPMs.

Source tar.gz

* aterm-%ATERMVERSION% * sdf2-bundle-%SDFVERSION%^?

Source RPM

* aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Redhat Linux RPM

Redhat 9.0: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

SuSE Linux RPM

SuSE 9.0: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Fedora Core RPM

Fedora Core 2: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Fedora Core 3: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Microsoft Windows Cygwin binaries

This release of the SDF2 Bundle did not install correctly on Cygwin. These issues have been fixed in the next release: sdf2-bundle-2.3.2.

Mac OS X binaries

* aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

* The *-macosx.tar.gz files contain a file README with installation instructions.

License

The SDF2 Bundle is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (GNU LGPL) as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details

Contents

SDF2 Bundle 2.3.1 consists of: * asc-support-2.2 * asf-library-1.2.1 * asf-support-1.4.2 * error-support-1.0.1 * pgen-2005-01-10 * pt-support-1.4 * sdf-support-2.1.3 * sglr-3.14 * toolbuslib-0.7.1 * tide-support-1.0

SDF2 Bundle 2.3.1 requires: * ATerm Library 2.4

News

This is a minor update of the SDF2 Bundle 2.3. It solves an compatibility problem with the latest release of the ATerm Library (2.4). Also, this release adds support for pkg-config.

Released August 26, 2005.

Download

See the installation instructions if you are not familiar with the standard installation procedure of tarballs or RPMs.

Source tar.gz

* aterm-%ATERMVERSION% * sdf2-bundle-%SDFVERSION%^?

Source RPM

* aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Redhat Linux RPM

Redhat 9.0: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

SuSE Linux RPM

SuSE 9.0: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Fedora Core RPM

Fedora Core 2: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Fedora Core 3: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Microsoft Windows Cygwin binaries

The *-cygwin.tar.gz files contain a file README with installation instructions.

* aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Mac OS X binaries

The *-macosx.tar.gz files contain a file README with installation instructions.

* aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Nix Packages

Open nixpkg files with nix-install-package. Installation of a Nix package is a one-click installation of package and all its dependencies.

i686-linux: * aterm-2.4^? * sdf2-bundle-2.3.2^?

powerpc-darwin: * aterm-2.4^? * sdf2-bundle-2.3.2^?

License

The SDF2 Bundle is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (GNU LGPL) as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details

Contents

SDF2 Bundle %SDFVERSION% consists of: * asc-support-2.2 * asf-library-1.2.1 * asf-support-1.4.2 * error-support-1.0.1 * pgen-2005-01-10 * pt-support-1.4 * sdf-support-2.1.3 * sglr-3.14 * toolbuslib-0.7.1 * tide-support-1.0

SDF2 Bundle %SDFVERSION% requires: * ATerm Library 2.4

News

This is a minor update of the SDF2 Bundle 2.3. It solves an compatibility problem with the latest release of the ATerm Library (2.4). Also, this release adds support for pkg-config.

Released November 4th, 2005.

Download

See the installation instructions if you are not familiar with the standard installation procedure of tarballs or RPMs.

Source tar.gz

* aterm-%ATERMVERSION% * sdf2-bundle-%SDFVERSION%^?

Source RPM

* aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Redhat Linux RPM

Redhat 9.0: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

SuSE Linux RPM

SuSE 9.0: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Fedora Core RPM

Fedora Core 2: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Fedora Core 3: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Microsoft Windows Cygwin binaries

The *-cygwin.tar.gz files contain a file README with installation instructions.

* aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Mac OS X binaries

The *-macosx.tar.gz files contain a file README with installation instructions.

* aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

Nix Packages

Open nixpkg files with nix-install-package. Installation of a Nix package is a one-click installation of package and all its dependencies.

i686-linux: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

powerpc-darwin: * aterm-%ATERMVERSION%^? * sdf2-bundle-%SDFVERSION%^?

License

The SDF2 Bundle is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (GNU LGPL) as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details

Contents

SDF2 Bundle %SDFVERSION% consists of: * asc-support-2.2 * asf-library-1.2.1 * asf-support-1.4.2 * error-support-1.0.1 * pgen-2005-01-10 * pt-support-1.4 * sdf-support-2.1.3 * sglr-3.14 * toolbuslib-0.7.1 * tide-support-1.0

SDF2 Bundle %SDFVERSION% requires: * ATerm Library 2.4.2

News

This is minor update of the SDF2 Bundle 2.3.2. It fixes a compilation problem of the SDF2 Bundle on GCC 4.0.x.

SDF is used by many individuals for many different purposes. This page lists the original applications of SDF and some of its premier applications.

The SDF syntax definition formalism is applied in two projects related to meta programming: the ASF+SDF Meta-Environment and Stratego/XT. Companies and researchers are using these environments for implementing various (source-to-source) program transformations.

ASF+SDF Meta-Environment

The ASF+SDF Meta-Environment is applied for the description of syntax, semantics, analysis, and transformation of (programming) languages and programs written in such programming languages. As the name suggests, SDF originated as a component of the ASF+SDF Meta-Environment.

The Meta-Environment uses SDF to parse input source code and to implement concrete syntax for source code patterns. The patterns are part of rewrite rules (equation) in the ASF formalism. ASF is used to implement source-to-source transformations, source analyses, compilers and interpreters.

More information can be found at http://www.meta-environment.org

Stratego/XT

Stratego/XT is the combination of the The Stratego program transformation language^? for strategic rewriting and the XT bundle of transformation tools.

In Stratego/XT SDF is used to define the syntax of (programming) languages and to generate tools like pretty-printers from these definitions. The power of SDF becomes especially clear in the use of concrete object syntax. This technique is applied by many Stratego/XT applications. At the Stratego/XT web you can find a list of applications of Stratego/XT.

Rascal

Rascal is a domain specific language for source code analysis, transformation and generation. It was bootstrapped using SDF and used SDF as a method for implementing parsers for object languages and for concrete syntax patterns. Currently Rascal implements embeds syntax definitions, very much like SDF2 but it is not using the SDF2 implementation anymore. Instead Rascal uses a general scannerless top-down parsing algorithm which is completely Java based.

Software Improvement Group.

The Software Improvement Group is a spin-off of the Dutch National Centre for Mathematics and Computer Science (CWI). The SIG is active in all fields of software renovation: the adaptation, integration and rebuilding of existing software systems. Currently the SIG provides services for documentation heneration, portfolio monitoring, risk assessments and migrations.

First Result

The company First Result applies SDF technology in the ASF+SDF Meta-Environment for the generation of code.

EPITA Research & Development Laboratory

The EPITA Research & Development Laboratory has developed C and C++ grammars in the Transformers Project. Disambiguation of C++ is performed on parse trees. Stratego/XT tools are used to implement parse and abstract syntax tree transformations.

-

The SDF bugzilla system is located here.

Use the components 'sglr' and 'pgen' to report bugs in the core SDF system, 'sdf-meta' for IDE bugs and 'unknown' if you just don't know.

Introduction

The SDF2 Bundle is an easy to install collection of packages related to the SDF2 syntax definition formalism. The packages are developed at the CWI. The main packages of the SDF2 Bundle are:

* PGEN - parser generator for SDF2 * SGLR - parser

The bundling related code is maintained by Martin Bravenboer. The packages themselves are maintained by members of SEN1 group at the CWI in the Netherlands.

Download

Release

The current release of the SDF2 Bundle is * SDF2 Bundle 2.3.3

Previous releases: * SDF2 Bundle 2.3.2 * SDF2 Bundle 2.3.1 * sdf2-bundle 2.3 * sdf2-bundle 2.2 * sdf2-bundle 2.1 * sdf2-bundle 2.0.1 * sdf2-bundle 1.6

Latest developments

The latest developments are available at: * Latest unstable sdf2-bundle

Online SDF2 and SGLR demo:

* http://www.syntax-definition.org/demo

SDF is an open-source project under the BSDLicense.

Contributing

• Please contribute bug reports, patches, and ideas for enhancement using our BugZilla instance. Thank you!
• If you would like to contribute a new component to the SDF project, or you would like to become a committer on existing SDF software, please contant Jurgen Vinju.
  • We are always interested in finding new colleagues!
  • We are always interested in add-ons and tools that support SDF grammar engineering. If you have made a valuable tool for SDF, we invite you to apply for hosting it on syntax-definition.org.

People

Maintainers

SDF is an open source project, originating from CWI in the Netherlands as part of The Meta-Environment. It is an independent piece of software now, developed by and contributed to by several people from CWI, TU Eindhoven, TU Delft and others.

The current developers/maintainers are:

• PGEN (SDF parse table generator)
  • Rob Economopoulos
  • Mark van den Brand
  • Jurgen Vinju

• SGLR (SDF parse table interpreter, "the parser")
  • Rob Economopoulos
  • Jurgen Vinju
  • Mark van den Brand

• SDF2 Bundle
  • Martin Bravenboer (Delft University of Technology)

Also note that SDF depends on other open source software such as the ATerm library and the UPTR (pt-support) parse forest representation library. For details about these components, please visit http://www.meta-environment.org. Any full SDF distribution includes these components, which are also open-source and released under the same license.

Contributors

Several people have contributed significantly to SDF:

• Merijn de Jonge
• Paul Klint
• Eelco Visser
• Jeroen Scheerder
• Pieter Olivier
• Hayco de Jong
• Taeke Kooiker

Also note that previous versions of SDF (as implemented in Centaur LISP) have been done by other people:

• See the Meta-Environment hall of fame

• A Quick Introduction to SDF describes the essence of SDF2 in 3 pages, but may be slightly out-of-date considering some details.
• Quick introduction to syntax analysis (pdf) is a general introduction to parsing.
• The Syntax Definition Formalism Reference Manual (pdf) is the definite guide to the syntax and semantics of SDF
• SDF Disambiguation Medkit for Programming Languages (pdf)
• An explanation of error messages of SDF (pdf) (under development)

• Publications

• Online Demos

• Glossary

This page is intended as a forum for discussion of all aspects of SDF2.

Tips and Tricks

SDF2 is a rich formalism. Here are some tips and tricks to use its full power.

• DisambiguationInSDF2

• AbstractSyntaxFromSDF2^?

Design and Implementation

SDF2 is still under development.

• SdfRequirements: The rationale behind the design of Sdf(2)

• Sdf.SDF2o2: Issues and plans for stabilizing the current version

• Sdf.SDF3: Considerations for the next generation

• • A bad idea to start thinking about this right now, makes people nervous. -- PK

• • Why does it make people nervous? A living language is always changing, users will come up with ways to improve the language. One can ignore such ideas or make an inventory that can be used as a basis for new development. -- EV

• • To keep the discussion about Sdf.SDF2o2 focussed it is good to have an Sdf.SDF3 bin in which we can store ideas that we don't want to think about for a while or ever -- JV

Comparison with other Formalisms

SDF2 is not the first syntax definition formalism ever designed. What are its features? What is different from other formalisms?

• SdfLanguage

• SDFvsSDF2^?: a comparison of Trash.SDFII with its predecessor

• BNFvsSDF2^?: a comparison with 'standard' syntax definitions

• YACCvsSDF2^?: a comparison with the classic

SDF in Context

SDF is used in combination with other formalisms and tools what are the consequences for the language?

• GrammarAnnotations^?

This should become a glossary of terminology related to SDF.

• Generalized LR
• Scannerless Generalized LR

Language	Version	Available in	View online
ASF		SDF Library	browse?
AsFix		SDF Library	browse?
AspectJ	5.0	AspectJ-front?	browse?
ATerm		SDF Library	browse?
Bibtex		Bibtex-tools?
Box		GPP	browse?
C	ad-hoc	StrategoXT?/c-tools?
C	C99	EPITA's Transformers Project
C	ANSI-C (?)	SDF Library	browse?
C++		EPITA's Transformers Project
C#	C# 2.0	csharp-front	browse
C Preprocessor		SDF Library	browse?
Dot (GraphViz)		Stratego/XT Utils
ECMAScript	Edition 3 (ECMA-262)	Under development in ECMAScript-front?
HQL		WebDSL	browse
Java	1.4	Java-front?
Java	1.5	Java-front?	browse?
JavaScript		See ECMAScript
Jimple		Jimple-front?	browse?
JSP		Under development in StringBorg?
LDAP Search Filters	RFC 4515	StringBorg?
Octave		Under development in the Stratego Octave Compiler
PHP	4	PHP-front	browse?
PHP	5	PHP-front	browse?
Prolog		Prolog-tools?
Shell		Under development in StringBorg?
Similix (subset of Scheme)		Similix in Stratego
SQL	92	SQL-front?
Stratego	0.9 - latest	StrategoXT?/stratego-front?
SDF		SDF Library 1.0	browse?
Tiger		Tiger in Stratego
URI	RFC 1738	Nix
VDM-SL	ISO/IEC 13817-1:1996	VooDooMFront
XML	1.0	Stratego/XT?
XPath	1.0	Under development in StringBorg?

Please add references to grammars you know about!

This list is maintained mostly by Martin Bravenboer and Karl Trygve Kalleberg. Please contact Martin if you cannot find a grammar or one of the links is broken.

Overview

The SDF syntax definition formalism allows a concise and natural expression of the syntax of a context-free language. SDF integrates lexical and context-free syntax in a single syntax formalism. The complete syntax of a language is thus defined in a single definition. SDF supports arbitrary context-free grammars. Therefore, SDF does not restrict the grammars to a subclass of the context-free grammars, such as LL or LALR. SDF syntax definitions can be modular. SDF modules can be reused in different syntax definitions. Disambiguation of grammars is not done by grammar hacking, but by applying special purpose disambiguation facilities in SDF, such as priorities, reject productions, and follow restrictions.

SDF is a declarative language. This means that a syntax definition can be used for different purposes then the usual application: the generation of a parser. Instead, SDF syntax definitions can be used to generate other tools from syntax definitions, e.g. pretty-printers and data type definitions.

Language Features

• Modules
• Integration of lexical and context-free syntax
• Character classes
• Regular expressions
• Disambiguation by relative priorities
• Disambiguation by associativity
• Disambiguation by preference
• Aliases
• Renaming and parameterization of modules
• Lookahead restrictions
• Reject productions
• Case-insensitive keywords

Design Features

Implementers of SDF2 will appreciate its orthogonality. Language features are defined, as much as possible, orthogonal with respect to each other. Despite providing a rich formalism at the level of the user language, the implementation only has to work on a small kernel formalism to which syntax definitions are transformed. Most features are expressed by a translation to the kernel formalism, which is performed by the SDF normalizer.

All symbols are first-class. For example, symbols can be used at the right-hande side of a production. This means that it is possible to define production rules that construct lists of symbols, optional symbols, and even literals.

Implementation Features

• Parser generation: SLR1 with special treatment of priorities
• Scannerless Generalized LR no separate scanner needed

Full bibliography of SDF

• CWI SEN1 publications
• Syntax Definition and Parsing publications in the list of publications by Eelco Visser

Language

• Disambiguation Filters For Scannerless Generalized LR Parsers -- CC 2002
• Syntax Definition for Language Prototyping -- Ph.D. Thesis 1997
• Parser Generation for Interactive Environments -- Ph.D. Thesis 1992
• Incremental Generation of Lexical Scanners -- TOPLAS 1992
• The Syntax Definition Formalism SDF - Reference Manual -- SIGPLAN Notices 1989
• Character Classes -- Technical Report 1997

Applications

• The Asf+Sdf Meta-Environment: a component-based language laboratory -- CC 2001

Syntax Definitions

• Declarative, Formal, and Extensible Syntax Definition for AspectJ. A Case for Scannerless Generalized-LR Parsing -- OOPSLA 2006

Code Generation

• Grammars as Contracts -- GCSE 2000
• Generation of abstract programming interfaces from syntax definitions -- JLAP 2000
• Object Oriented Tree Traversal with JJForester -- LDTA 2001

• An Architecture for Context-Sensitive Formatting - ICSM 2005
• Pretty-Printing for Software Reengineering -- ICSM 2002
• A Pretty-Printer for Every Occasion -- CoSET 2000

Embedding and Modularity

• Generalized Type-Based Disambiguation of Meta Programs with Concrete Object Syntax -- GPCE 2005
• Type-driven automatic quotation of concrete object code in meta programs. RISE 2005
• Concrete Syntax for Objects. Domain-specific language embedding and assimilation without restrictions -- OOPSLA 2004
• Meta Programming with Concrete Object Syntax -- GPCE 2002
• Retrofitting the AutoBayes Program Synthesis System with Concrete Syntax

Island Grammars

• Lightweight Impact Analysis using Island Grammars -- IWPC 2002
• Generating Robust Parsers using Island Grammars -- WCRE 2001

Related Software

This page lists known third-party software that is available for SDF

IDE

• The SDF Meta-Environment is an IDE for SDF. It is currently not released separatedly from the ASF+SDF Meta-Environment. Contact us if this is needed.
• The ASF+SDF Meta-Environment is an IDE for ASF+SDF. This IDE can be used as an IDE for SDF.

Grammar manipulation

• SDF weaver is a tool for merging production attributes into a grammar.

Code Generation

• ApiGen generates C or Java APIs from an SDF syntax definition.

• Strafunski and Sdf2Haskell provide support for generic programming and language processing in the functional programming language Haskell. Sdf2Haskell implements the derivation of algebraic datatypes from SDF syntax definitions. The Haskell ATerm library can be used to import the results of the SGLR parser.

• HaGLR is an implementation of Generalized LR parsing in Haskell, and also implements an SDF front-end, which is an extension of the Sdf2Haskell generator.

• Repleo is a template based code generated based on SDF which features static syntactic correctness.

Pretty-Printer Generation

• GPP is a collection of tools for pretty-printing and pretty-printer generation. It supports the SDF syntax definition formalism. GPP is part of StrategoXT.
• Pandora is a pretty printing tool for SDF parse trees. It is included in the 2.6 release of SDF. Older versions are part of The Meta-Environment

Testing

• parse-unit is a tool for unit-testing SDF syntax definitions. It is part of StrategoXT.

Metrics

• SdfMetz -- A SDF monitoring tool. From the website: "is a tool to support grammar engineering. It calculates metrics and performs miscellaneus analyzes (like output the grammar graph or view the non-singleton levels of a grammar). This tool was implemented to fill the gap of grammar measuring and analyzes tools."
• Meta-Environment contains a set of SDF metrics and visualizations, as inspired by SdfMetz.

The design of SDF is the result of a number of requirements. This page discusses these requirements.

Completeness of Syntax Definition

All aspects of the syntax of a language are defined in one specification and in one formalism. This entails that lexical syntax, context-free syntax and disambiguation information are all specified in the same formalism.

In contrast to LEX/YACC where lexical and context-free syntax are defined in separate formalisms.

Orthogonality

Features that are available for some type of expression in one context should be available for that type of expression in another context as well and should mean the same thing.

For example, the iteration construct {A B}* should mean the same thing when used in lexical syntax or context-free syntax.

Modular

It should be possible to extend a syntax definition with additional productions, i.e., syntax definitions should be modular.

Expressive

Frequently occurring syntax patterns such as lists and optionals should not have to be defined every time. In other words SDF should support the common extensions of Extended BNF.

Extensible

The formalism itself should be extensible. It should possible to add some new abstractions to the formalism.

SDF is released under the BSD open-source license.

The latest source release of SDF is:

• SDF 2.6.2 source bundle

A binary distribution for Linux/x86 is also available:

• SDF 2.6.3 linux binary distribution

The SDF bundle contains:

• the SGLR parser
• the SDF2 parser generator
• the Pandora formatting tool, based on Box.
• the ATerm library (C library)

Java programmers may be interested in a working Java version of SGLR (the parse table interpreter):

• http://www.strategoxt.org/Stratego/JSGLR

Older releases can be found here.

Name

sdf2table

Synopsis

sdf2table [-m ma[-s] [-i sdf-definition] [-o parse-table]

Description

The utility sdf2table generates a parse table from an SDF syntax definition.

The syntax definition is required to be in the SDF2 format.

Options

input and output
-i	file	input from file (default: all file arguments)
-o	file	output to file (default: inputfile.tbl)
-m	name	parse table is generated for module name (default: Main)
output format
-b		write output in Binary AsFix (BAF) format
-t		write output in plain text format
control operation
-n		only normalization of grammar
-s		check sdf definition and show warnings on stderr
runtime information
-l		display statistic information
-v		verbose mode
meta information
-h		display help information (usage)
-V		reveal program version (i.e. 1.13)

See also

• SGLR

The SDF parser (SGLR) reads a file that contains the parse table. The format for this file and its implementation is a part of the SDF bundle. This part is called ptable-support. You will find a definition of the files format in the source code of the package.

The format is versioned for checking compatibility between the tables generated by the parse table generator and tools that read the tables, such as SGLR.

Version 4 Parse Table Format

The version 4 (now outdated) parse table format is explained here. The newer formats are very similar, but some details are different. For now, please refer to the source code for details.

parse-table(<term>,<term>,<term>,states([<list>]),priorities(<term>))

* The first <term> is a version number, currently 4. * The second <term> is the number of the initial state, normally 0. * The third <term> is a list of labels of the form label(<term>,<int>), where <term> represents a production rule and <int> the label number. The production rule is represented as an ATerm and has, e.g., the form: prod([sort("<START>"),char-class([256])],sort("<Start>"),no-attrs) * The states have the form: state-rec(<int>,[<list>],[<list>]) where <int> represents the state number, the first list the list of gotos, and the second list the list of actions. * A goto item looks like goto([<list>],<int>), this list is a list of single characters, character ranges, and/or label numbers. The <int> is the state number to which the parser has to jump. * A action item looks like action([<list>],[<list>]), where the first list is a list of single characters and/or character ranges. The second list are the actions that have to be performed: * reduce(<int>,<int>,<int>): first <int> represents the number of members in of the production rule with label given as second <int>, and the last <int> represent that "status" of a production rule, prefer, avoid, reject, or normal. * reduce(<int>,<int>,<int>,<term>): the <term> represents a lookahead set greater than one. Lookaheads of more than one character are performed dynamically. * shift(<int>): the <int> represent the new state after shifting the current character. * accept * The priorities is a list of relations between 2 production rules: * left-prio(<int>,<int>) * right-prio(<int>,<int>) * non-assoc-prio(<int>,<int>) * gtr-prio(<int>,<int>) where the <int>s are the labels of the production rules involved. left, right, and non-assoc are associativity attributes used within the Tools.SDF definition. gtr is the priority relation.

Web	TWiki Site Map	Use to...
Main	The Main web is dedicated to the maintenance of this website. This is the place to discuss meta-issues such as what style to use, how best to organize a survey, what the ideal topic size is, how to refer to papers, what the preferred layout of the site should be, etc.	...
TWiki	Welcome, Registration, and other StartingPoints; TWiki history & Wiki style; All the docs...	...discover TWiki details, and how to start your own site.
Gmt	Generative Model Transformer
Gpce
Octave	The Stratego web is the home of Stratego, a language for program transformation based on the paradigm of rewriting strategies. The aim of this language is to provide an expressive and declarative language for expressing all kinds of program transformations. The web includes publications on Stratego, download of the StrategoCompiler, documentation, and descriptions of applications.	...
Sandbox	Sandbox test area with all features enabled.	...experiment in an unrestricted hands-on web.
Sdf	The Sdf web is dedicated to the modular syntax definition formalism SDF. Here you can find implementations, pointers to download pages, syntax definitions for common languages, discussions about new features and implementatios of SDF, and tips and tricks for using the formalism.	...
SdfBackup	The Sdf web is dedicated to the modular syntax definition formalism SDF. Here you can find implementations, pointers to download pages, syntax definitions for common languages, discussions about new features and implementatios of SDF, and tips and tricks for using the formalism.	...
Stratego	The Stratego web is the home of Stratego, a language for program transformation based on the paradigm of rewriting strategies. The aim of this language is to provide an expressive and declarative language for expressing all kinds of program transformations. The web includes publications on Stratego, download of the StrategoCompiler, documentation, and descriptions of applications.	...
Sts	The Sofware Transformation Systems wiki
Tiger	Home of the Tiger in Stratego project, which is concerned with the exploration of transformation techniques in compilation using an implementation of a Tiger compiler.	...
Tools	The Tools web is the home of the XT? bundle of program transformation tools. XT is an open framework for program transformation based on the ATerm format for exchange of programs between tools. The bundle includes packages for parsing, pretty-printing, term rewriting, and grammar recovery. It also contains a distribution of the SDF2? GrammarBase?. The OnlinePackageBase is an open collection of packages for program transformation supporting package bundling on demand.	...
Transform	The Transform web is an attempt to get an overview of program transformation research and application. In the first place the web is a collection of resources such as pointers to researchers, conferences, journals, summaries and reviews of papers, and tools for implementing transformation systems. In the second place the Transform web attempts to bring structure in the world of program transformation by means of categories, taxonomies such as the TransformationTaxonomy, and entry points such as the ReengineeringWiki and the DeCompilation page.	...
You can use color coding by web for identification and reference. This table is updated automatically based on WebPreferences settings of the individual webs. Contact webmaster@strategoxt.org if you need a separate collaboration web for your team. See also AdminTools.

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= See recent changes in the web = Subscribe to get notified of changes by e-mail

Web Header Menu	07 Jun 2013 - 09:21	TWiki Guest
Web Left Bar	20 Apr 2011 - 13:32	Lennart Kats
Development Tools	20 Apr 2011 - 13:31	Lennart Kats
Sdf Publications	20 Apr 2011 - 13:24	Lennart Kats
Sdf Development	20 Apr 2011 - 13:03	Lennart Kats
Sdf Related Software	20 Apr 2011 - 13:03	Lennart Kats
Sdf Software	20 Apr 2011 - 13:02	Lennart Kats
Sdf Documentation	20 Apr 2011 - 13:02	Lennart Kats
Web Home	20 Apr 2011 - 13:01	Lennart Kats
Web News	20 Apr 2011 - 12:57	Lennart Kats
Sdf Applications	30 Nov 2010 - 14:31	Jurgen Vinju
Old Releases	30 Nov 2010 - 14:29	Jurgen Vinju
Sdf Demos	17 Sep 2008 - 15:28	Jurgen Vinju
Sdf Grammars	30 Jun 2008 - 23:21	karltk?
Sglr Parse Table Format	30 Jun 2008 - 18:36	karltk?
SGLR	30 Jun 2008 - 09:40	karltk?
Sdf 2 Bundle Release 232	15 Mar 2008 - 22:53	Martin Bravenboer
Sdf 2 Bundle Release 233	15 Mar 2008 - 22:27	Martin Bravenboer
Mailing List	11 Mar 2008 - 21:37	Jurgen Vinju
Sdf Bugs	11 Mar 2008 - 20:54	Jurgen Vinju
BSDLicense	11 Mar 2008 - 20:41	Jurgen Vinju
AQuick Introduction To SDF	11 Mar 2008 - 20:29	Jurgen Vinju
Sdf Bundle	26 Feb 2008 - 10:27	Arnold Lankamp?
Sdf 2 Bundle Release 16	26 Feb 2008 - 10:24	Arnold Lankamp?
Sdf 2 Bundle Release 201	26 Feb 2008 - 10:24	Arnold Lankamp?
Sdf 2 Bundle Release 21	26 Feb 2008 - 10:24	Arnold Lankamp?
Sdf 2 Bundle Release 23	26 Feb 2008 - 10:23	Arnold Lankamp?
Sdf 2 Bundle Release 22	26 Feb 2008 - 10:23	Arnold Lankamp?
Sdf 2 Bundle Release 231	26 Feb 2008 - 10:23	Arnold Lankamp?
Web Preferences	25 Feb 2008 - 14:11	Arnold Lankamp?
Web Statistics	16 Dec 2007 - 01:12	TWiki Guest
Sdf Language	26 Nov 2007 - 22:37	Jurgen Vinju
Web Menu	29 Jan 2007 - 22:14	paulk?
Sdf Glossary	24 Dec 2004 - 00:59	Martin Bravenboer
Web Changes	22 Dec 2004 - 17:39	Martin Bravenboer
Web Tools	29 Nov 2004 - 17:38	Martin Bravenboer
Generalized LR	18 Jul 2004 - 14:38	Martin Bravenboer
Grammar Testing	25 Feb 2004 - 11:15	Martin Bravenboer
Sdf To Table	17 Feb 2004 - 11:35	Martin Bravenboer
PGEN	17 Feb 2004 - 11:33	Martin Bravenboer
Web Rss	09 Feb 2004 - 16:04	Martin Bravenboer
Sdf Requirements	09 Feb 2004 - 14:42	Martin Bravenboer
SDFby Example	09 Feb 2004 - 14:41	Martin Bravenboer
SDF2 o 2	09 Feb 2004 - 14:40	Martin Bravenboer
SDF2 Publications	09 Feb 2004 - 14:39	Martin Bravenboer
SDF3	09 Feb 2004 - 13:53	Martin Bravenboer
Sdf Forum	09 Feb 2004 - 13:29	Martin Bravenboer
Disambiguation In SDF2	09 Feb 2004 - 13:21	Martin Bravenboer
Disambiguation Filters For Scannerless Gener...	09 Feb 2004 - 13:17	Martin Bravenboer
Lexical Versus Context Free Restrictions	09 Feb 2004 - 13:01	Martin Bravenboer

Number of topics: 50

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SDF is a language for defining syntax. It provides for an unprecedented level of conciseness in syntax definitions. First, syntax can be defined in modules. Second, lexical and context-free syntax are integrated in a single formalism in which the complete syntax of a language can be defined. Third, SDF includes declarative disambiguation constructs. Therefore, there is no need to introduce non-terminals to deal with ambiguities in a language. Some useful places to start: An overview of the unique features of SDF Pointers to SDF documentation Download the implementation of SDF Research papers about SDF Find SDF grammars for many languages here Subscribe to the mailing list for announcements and discussions. Organization of the development of SDF related software How to report bugs.

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Statistics for TWiki.Sdf Web

Month:	Topic views:	Topic saves:	File uploads:	Most popular topic views:	Top contributors for topic save and uploads:
Dec 2007	4149	0	0	471 WebHome 373 WebStatistics 324 WebRss 172 SdfGrammars 168 SdfSoftware 151 SdfLanguage 115 SdfDevelopment 113 SdfPublications 109 SdfDocumentation 107 SGLR  95 WebNews
Nov 2007	7839	26	0	918 WebHome 597 WebRss 428 WebStatistics 321 SdfGrammars 278 SdfSoftware 253 SdfLanguage 247 GeneralizedLR 219 SdfDocumentation 205 SGLR 181 SdfPublications 171 WebNews	24 JurgenVinju   2 MartinBravenboer
Oct 2007	8011	0	0	1027 WebHome 595 WebStatistics 452 WebRss 329 SdfSoftware 299 SdfGrammars 284 SdfLanguage 229 SdfDocumentation 200 SdfPublications 196 WebNews 177 SdfApplications 176 SdfBundle
Sep 2007	8208	0	0	903 WebStatistics 824 WebHome 583 WebRss 279 SdfGrammars 255 SdfSoftware 254 SdfLanguage 207 SdfPublications 191 SdfDocumentation 180 SdfBundle 177 GeneralizedLR 171 SGLR
Aug 2007	10840	0	0	1477 WebStatistics 835 WebHome 664 WebRss 397 SdfGrammars 343 SdfLanguage 340 SdfSoftware 270 SdfDocumentation 235 SGLR 224 WebChanges 219 SdfBundle 217 WebNews
Jul 2007	13935	0	0	1123 WebStatistics 980 WebHome 655 SdfGrammars 487 WebRss 452 SdfSoftware 420 SdfLanguage 406 WebNews 342 SdfPublications 331 GeneralizedLR 319 SdfDocumentation 300 SGLR
Jun 2007	8904	0	0	842 WebHome 475 WebRss 338 SdfGrammars 319 SdfLanguage 319 SdfSoftware 311 WebStatistics 261 GeneralizedLR 259 SdfDocumentation 253 Sdf2BundleRelease22 227 WebNews 225 SdfBundle
May 2007	6711	0	0	638 WebHome 539 WebRss 441 WebStatistics 303 SdfGrammars 240 SdfSoftware 204 SdfDocumentation 195 SdfLanguage 191 GeneralizedLR 154 SdfBundle 149 SdfPublications 148 SGLR
Apr 2007	7139	0	0	704 WebHome 593 WebStatistics 403 WebRss 304 SdfGrammars 284 SdfSoftware 244 SdfLanguage 214 SdfBundle 190 GeneralizedLR 182 SdfDocumentation 159 WebNotify 143 SdfPublications
Mar 2007	7022	0	0	788 WebHome 503 WebStatistics 447 WebRss 399 SdfGrammars 300 SdfSoftware 197 SdfBundle 178 SdfPublications 177 SdfLanguage 170 SdfDocumentation 165 WebNews 140 GeneralizedLR
Feb 2007	6882	8	0	645 WebHome 495 WebStatistics 421 SdfGrammars 372 WebRss 278 SdfSoftware 233 SdfBundle 183 GeneralizedLR 183 SdfLanguage 156 SdfDocumentation 153 SdfPublications 145 Sdf2BundleRelease23	8 MartinBravenboer
Jan 2007	8295	3	0	1231 WebStatistics 753 WebHome 443 WebRss 412 SdfGrammars 325 SdfSoftware 234 SdfBundle 208 SdfLanguage 200 GeneralizedLR 182 SdfDocumentation 162 SGLR 160 SdfPublications	3 MartinBravenboer
Dec 2006	5986	7	0	714 WebHome 481 WebRss 221 WebStatistics 220 SdfSoftware 218 SdfGrammars 170 SdfBundle 170 SdfLanguage 170 SdfDocumentation 142 SdfApplications 138 GeneralizedLR 126 Sdf2BundleRelease22	7 MartinBravenboer
Nov 2006	5591	12	0	585 WebHome 509 WebStatistics 276 SdfGrammars 213 WebRss 207 SdfSoftware 170 SdfLanguage 159 SdfBundle 141 SdfDocumentation 140 GeneralizedLR 112 PGEN 111 SGLR	12 MartinBravenboer
Oct 2006	5514	0	0	647 WebHome 479 WebStatistics 266 SdfGrammars 215 SdfSoftware 204 WebRss 153 SdfLanguage 141 SdfDocumentation 140 SdfBundle 139 GeneralizedLR 137 WebNotify 122 SGLR
Sep 2006	5526	1	0	585 WebHome 504 WebStatistics 222 SdfGrammars 184 SdfSoftware 165 WebRss 143 SdfLanguage 138 SdfDocumentation 127 GeneralizedLR 118 SdfBundle 113 WebNews 112 PGEN	1 MartinBravenboer
Aug 2006	7832	2	0	770 WebHome 765 WebStatistics 275 GeneralizedLR 263 WebRss 255 SdfGrammars 252 SdfSoftware 214 SdfLanguage 199 WebChanges 195 SdfDocumentation 185 SGLR 183 WebNews	2 MartinBravenboer
Jul 2006	9437	1	0	1221 WebStatistics 922 WebHome 371 SdfGrammars 324 SdfSoftware 287 SdfLanguage 255 SdfDocumentation 247 WebNews 234 GeneralizedLR 224 PGEN 215 WebNotify 214 SdfBundle	1 ChristianoBraga
Jun 2006	9398	0	0	1217 WebStatistics 818 WebHome 368 SdfGrammars 350 SdfSoftware 251 GeneralizedLR 231 WebNotify 225 SdfLanguage 224 SdfDocumentation 216 WebChanges 210 WebNews 202 SdfBundle
May 2006	14645	0	0	2364 WebStatistics 1227 WebHome 611 SdfGrammars 524 SdfSoftware 413 SdfLanguage 397 WebNotify 382 WebNews 368 SdfDocumentation 356 SGLR 350 WebChanges 330 GeneralizedLR
Apr 2006	10797	12	0	1168 WebHome 902 WebStatistics 432 SdfGrammars 384 SdfSoftware 380 WebChanges 344 WebNews 324 WebNotify 307 SdfDocumentation 302 SdfBundle 301 SdfLanguage 259 WebSearch	12 MartinBravenboer
Mar 2006	9869	0	0	1455 WebHome 843 WebStatistics 355 SdfSoftware 338 SdfGrammars 317 SdfLanguage 282 WebNews 270 SdfDocumentation 264 SdfBundle 235 SGLR 233 WebChanges 220 WebSearch
Feb 2006	6493	0	0	1037 WebHome 535 WebStatistics 240 SdfSoftware 231 SdfGrammars 198 WebNews 181 GeneralizedLR 174 SdfDocumentation 162 SdfLanguage 154 Sdf2BundleRelease23 145 SdfApplications 143 PGEN
Jan 2006	7291	0	0	1073 WebHome 498 WebStatistics 299 SdfSoftware 243 SdfGrammars 223 SdfLanguage 198 GeneralizedLR 183 WebNews 179 WebRss 173 SdfDocumentation 158 SGLR 156 SdfApplications
Dec 2005	8222	0	0	1116 WebHome 573 WebStatistics 334 SdfSoftware 318 SdfGrammars 264 WebNews 228 GeneralizedLR 226 SdfDocumentation 225 SdfLanguage 206 WebRss 203 WebChanges 189 WebNotify
Nov 2005	7030	4	0	1027 WebHome 399 WebStatistics 299 SdfSoftware 249 SdfGrammars 236 SdfLanguage 233 WebNews 203 WebIndex 198 SdfDocumentation 193 WebChanges 186 GeneralizedLR 178 WebNotify	4 MartinBravenboer
Oct 2005	6078	1	0	746 WebHome 280 SdfSoftware 264 SdfGrammars 220 SdfDocumentation 209 SdfLanguage 182 GeneralizedLR 177 WebStatistics 175 WebNews 168 Sdf2BundleRelease23 157 WebIndex 156 WebChanges	1 MartinBravenboer
Sep 2005	4628	0	0	519 WebHome 373 WebStatistics 204 SdfGrammars 189 SdfSoftware 173 SdfDocumentation 142 SdfLanguage 137 GeneralizedLR 121 WebChanges 119 WebNews 109 Sdf2BundleRelease23 107 WebNotify
Aug 2005	4476	12	0	627 WebHome 426 WebRss 244 SdfSoftware 205 SdfGrammars 189 SdfLanguage 161 WebIndex 156 SdfDocumentation 137 WebStatistics 129 WebChanges 122 SGLR 118 Sdf2BundleRelease23	12 MartinBravenboer
Jul 2005	4281	0	0	587 WebHome 271 SdfSoftware 174 SdfDocumentation 165 SdfLanguage 154 SdfGrammars 150 WebIndex 129 WebNotify 122 SGLR 120 Sdf2BundleRelease23 114 WebChanges 106 PGEN
Jun 2005	2829	1	0	443 WebHome 173 SdfDocumentation 146 SdfSoftware 132 SdfLanguage 114 SdfGrammars 111 SGLR  84 PGEN  82 WebNews  78 AQuickIntroductionToSDF  77 SdfBundle  76 WebNotify	1 MartinBravenboer
May 2005	3025	0	0	551 WebHome 166 SdfDocumentation 145 SdfLanguage 129 SdfSoftware 116 SdfGrammars 108 WebChanges 102 AQuickIntroductionToSDF  92 WebNotify  83 SdfPublications  80 SGLR  76 Sdf2BundleRelease23
Apr 2005	2958	0	0	424 WebHome 156 SdfDocumentation 154 SdfGrammars 141 SdfLanguage 128 SdfSoftware 109 Sdf2BundleRelease23  98 AQuickIntroductionToSDF  86 GrammarBase  85 SdfPublications  79 PGEN  78 WebNews
Mar 2005	2333	3	0	353 WebHome 148 SdfGrammars 144 SdfDocumentation 113 SdfLanguage 104 SdfSoftware  80 GrammarBase  77 AQuickIntroductionToSDF  74 WebChanges  71 Sdf2BundleRelease23  63 SGLR  59 SdfApplications	3 MartinBravenboer
Feb 2005	2613	10	0	374 WebHome 191 SdfDocumentation 152 SdfGrammars 144 SdfLanguage 116 SdfSoftware 105 AQuickIntroductionToSDF  88 Sdf2BundleRelease23  85 GrammarBase  79 SdfApplications  68 SdfBundle  66 SGLR	10 MartinBravenboer
Jan 2005	2169	8	0	401 WebHome 172 SdfDocumentation 130 SdfGrammars 120 AQuickIntroductionToSDF 115 SdfLanguage  95 SdfSoftware  88 GrammarBase  54 Sdf2BundleRelease23  53 SdfPublications  52 SdfBundle  52 WebChanges	8 MartinBravenboer
Dec 2004	2368	86	0	480 WebHome 157 SdfDocumentation 146 SdfLanguage 122 SdfSoftware 119 SdfGrammars  88 AQuickIntroductionToSDF  70 SGLR  70 SdfPublications  68 SdfApplications  65 GrammarBase  57 WebChanges	86 MartinBravenboer
Nov 2004	2258	1	0	348 WebHome 252 WebRss 126 SdfLanguage 122 SdfDocumentation  94 AQuickIntroductionToSDF  90 SdfGrammars  85 SGLR  70 SdfSoftware  68 GrammarBase  67 SdfApplications  61 SdfPublications	1 MartinBravenboer
Oct 2004	1526	0	0	352 WebHome 103 SdfLanguage  94 SdfDocumentation  74 SdfGrammars  68 WebRss  66 GrammarBase  66 AQuickIntroductionToSDF  56 robots.txt  48 SdfSoftware  46 SdfApplications  43 SGLR
Sep 2004	2072	5	0	697 WebHome  94 SdfLanguage  89 GrammarBase  81 robots.txt  80 SdfDocumentation  67 SdfGrammars  62 SdfSoftware  62 GeneralizedLR  54 SdfApplications  51 SGLR  46 SdfPublications	5 MartinBravenboer
Aug 2004	1358	1	0	283 WebHome  87 SdfDocumentation  82 SdfLanguage  59 SdfGrammars  57 GrammarBase  55 robots.txt  48 SGLR  46 GeneralizedLR  42 SdfSoftware  42 AQuickIntroductionToSDF  41 SdfApplications	1 MartinBravenboer
Jul 2004	1660	7	0	318 WebHome 125 SdfLanguage 111 SdfDocumentation  88 GrammarBase  82 SdfGrammars  67 SdfApplications  58 SdfSoftware  56 SGLR  54 SdfPublications  53 AQuickIntroductionToSDF  50 WebNews	7 MartinBravenboer
Jun 2004	1584	5	0	644 WebHome  78 SdfDocumentation  70 SdfLanguage  70 GeneralizedLR  51 GrammarBase  50 AQuickIntroductionToSDF  47 SdfGrammars  44 SdfApplications  44 SGLR  43 SdfPublications  41 SdfSoftware	5 EelcoVisser
May 2004	1339	28	0	325 WebHome 107 SdfLanguage  77 SdfDocumentation  74 GeneralizedLR  72 GrammarBase  58 SdfSoftware  51 SdfGrammars  42 SdfPublications  39 WebNews  33 robots.txt  33 SdfDemos	28 MartinBravenboer
Apr 2004	1451	0	0	229 WebHome  93 GrammarBase  83 SdfLanguage  56 SdfDocumentation  53 SdfGrammars  43 SdfSoftware  40 AQuickIntroductionToSDF  36 PGEN  35 SdfBugs  34 SdfApplications  34 SDFbyExample
Mar 2004	991	2	0	255 WebHome  79 GrammarBase  65 SdfLanguage  55 SdfDocumentation  44 SdfSoftware  44 SdfGrammars  35 AQuickIntroductionToSDF  31 SdfPublications  30 SdfApplications  25 SGLR  25 GeneralizedLR	2 MartinBravenboer
Feb 2004	1108	24	0	259 WebHome  75 SdfDocumentation  64 GrammarBase  63 SdfLanguage  51 AQuickIntroductionToSDF  47 SdfSoftware  47 SdfGrammars  32 SdfApplications  31 SdfPublications  29 SGLR  26 GeneralizedLR	24 MartinBravenboer
Jan 2004	469	86	0	159 WebHome  68 WebChanges  25 WebLeftBar  17 SdfGrammars  15 SdfApplications  13 WebPreferences  10 SdfLanguage  10 SdfDocumentation   9 WebStatistics   9 SdfSoftware   9 PGEN	84 MartinBravenboer   1 JurgenVinju   1 EelcoDolstra
Dec 2003	540	0	0	440 WebStatistics  23 WebHome  10 WebChanges   9 WebPreferences   9 WebNotify   8 WebIndex   7 WebSearch   6 WebLeftBar   4 WebTools   4 WebNews   4 WebChanges500
Nov 2003	48	0	0	13 WebHome   4 WebSearch   4 WebPreferences   4 WebChanges   3 WebStatistics   2 WebTools   2 WebNotify   2 WebNews   2 WebIndex   2 WebLeftBar   2 WebChanges500
Oct 2003	451	1	0	381 WebStatistics   7 WebNotify   7 WebHome   6 WebPreferences   6 WebIndex   6 WebLeftBar   6 WebChanges   4 WebTools   4 WebSearch   4 WebNews   4 WebChanges500	1 MartinBravenboer
Sep 2003	36	0	0	9 WebHome   7 WebStatistics   4 WebSearch   4 WebPreferences   4 WebNotify   4 WebIndex   3 WebChanges
Aug 2003	62	0	0	8 WebStatistics   6 WebPreferences   6 WebHome   5 WebSearch   5 WebNotify   5 WebIndex   5 WebChanges   4 SiteMap   3 WebNews   3 WebLeftBar   3 WebChanges500
Jul 2003	67	0	0	9 WebHome   7 WebStatistics   6 WebPreferences   6 WebChanges   6 SiteMap   5 WebIndex   5 WebLeftBar   4 WebSearch   4 WebNotify   3 WebTools   3 WebChanges500
Jun 2003	48	0	0	7 WebHome   5 WebStatistics   4 WebTools   4 WebNotify   4 WebNews   4 WebIndex   4 WebChanges   4 SiteMap   3 WebSearch   3 WebPreferences   2 WebChanges200
May 2003	9	0	0	8 WebHome   1 WebChanges
Apr 2003	16	0	0	4 WebHome   2 WebStatistics   2 WebPreferences   2 WebNotify   1 WebTools   1 WebSearch   1 WebNews   1 WebIndex   1 WebChanges   1 SiteMap
Mar 2003	0	0	0
Feb 2003	14	0	0	6 WebHome   1 WebTools   1 WebSearch   1 WebNews   1 WebIndex   1 WebLeftBar   1 WebChanges500   1 WebChanges   1 SiteMap
Jan 2003	5	0	0	1 WebSearch   1 WebPreferences   1 WebIndex   1 WebChanges100   1 WebChanges
Dec 2002	10	0	0	4 WebHome   1 WebTools   1 WebStatistics   1 WebNotify   1 WebNews   1 WebIndex   1 SiteMap
Nov 2002	5	0	0	1 WebSearch   1 WebPreferences   1 WebHome   1 WebLeftBar   1 WebChanges
Oct 2002	37	0	0	7 WebHome   6 WebStatistics   3 WebSearch   3 WebPreferences   3 WebChanges   2 WebTools   2 WebNotify   2 WebNews   2 WebIndex   2 SiteMap   1 WebLeftBar
Sep 2002	7	3	0	3 WebPreferences   2 WebLeftBar   1 WebHome   1 SiteMap	3 EelcoVisser

Notes:

• Do not edit this topic, it is updated automatically. (You can also force an update)
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