https://github.com/Chrriis/RRDiagram

Generate railroad diagrams from code or BNF, generate BNF from code
https://github.com/Chrriis/RRDiagram

Last synced: 5 days ago
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Generate railroad diagrams from code or BNF, generate BNF from code

• Host: GitHub
• URL: https://github.com/Chrriis/RRDiagram
• Owner: Chrriis
• License: apache-2.0
• Created: 2013-05-05T14:46:42.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2024-01-26T18:58:53.000Z (10 months ago)
• Last Synced: 2024-08-01T12:29:35.120Z (3 months ago)
• Language: Java
• Size: 130 KB
• Stars: 145
• Watchers: 6
• Forks: 30
• Open Issues: 5
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
RRDiagram

=========

Generate railroad diagrams from code or BNF. Generate BNF from code.

RR Diagram is a Java library that generates railroad diagrams (also called syntax diagrams) from code or from BNF notation. The output format is a very compact SVG image which can be integrated to web pages and where rules can contain links.

RR Diagram can also be used to generate BNF notation from a model.

The generated output was inspired from this online-only version .

Binaries can be found on the [SourceForge page](https://sourceforge.net/projects/rrdiagram/).

Example

=======

This is the kind of diagrams that can get generated:

![H2 Select](http://rrdiagram.sourceforge.net/H2Select.svg)

The above is generated using the right conversion options on this BNF:


H2_SELECT = 

'SELECT' [ 'TOP' term ] [ 'DISTINCT' | 'ALL' ] selectExpression {',' selectExpression} \

'FROM' tableExpression {',' tableExpression} [ 'WHERE' expression ] \

[ 'GROUP BY' expression {',' expression} ] [ 'HAVING' expression ] \

[ ( 'UNION' [ 'ALL' ] | 'MINUS' | 'EXCEPT' | 'INTERSECT' ) select ] [ 'ORDER BY' order {',' order} ] \

[ 'LIMIT' expression [ 'OFFSET' expression ] [ 'SAMPLE_SIZE' rowCountInt ] ] \

[ 'FOR UPDATE' ];



Usage

=====

The diagram model represents the actual constructs visible on the diagram.

To convert a diagram model to SVG:

```Java

RRDiagram rrDiagram = new RRDiagram(rrElement);

RRDiagramToSVG rrDiagramToSVG = new RRDiagramToSVG();

String svg = rrDiagramToSVG.convert(rrDiagram);

```

The grammar model represents a BNF-like grammar.

It can be converted to a diagram model:

```Java

Grammar grammar = new Grammar(rules);

GrammarToRRDiagram grammarToRRDiagram = new GrammarToRRDiagram();

for(Rule rule: grammar.getRules()) {

  RRDiagram rrDiagram = grammarToRRDiagram.convert(rule);

  // Do something with diagram, like get the SVG.

}

```

The grammar model can be created from code, or can read BNF syntax:

```Java

BNFToGrammar bnfToGrammar = new BNFToGrammar();

Grammar grammar = bnfToGrammar.convert(reader);

// Do something with grammar, like get the diagram for SVG output.

```

The grammar model can also be saved to BNF syntax:

```Java

GrammarToBNF grammarToBNF = new GrammarToBNF();

// Set options on the grammarToBNF object

String bnf = grammarToBNF.convert(grammar);

```

BNF Syntax

==========

The supported BNF subset when reading is the following:


- definition

    =

    :=

    ::=

- concatenation

    ,

    <whitespace>

- termination

    ;

- alternation

    |

- option

    [ ... ]

    ?

- repetition

    { ... } => 0..N

    expression* => 0..N

    expression+ => 1..N

    <digits> * expression => <digits>...<digits>

    <digits> * [expression] => <0>...<digits>

    <digits> * expression? => <0>...<digits>

- grouping

    ( ... )

- literal

    " ... " or ' ... '

- special characters

    (? ... ?)

- comments

    (* ... *)



When getting the BNF syntax from the grammar model, it is possible to tweak the kind of BNF to get by changing some options on the converter.

License

=======

This library is provided under the ASL 2.0.