Tool for generating railroad diagram used on json.org

There is an Online Railroad Diagram Generator. It creates SVG syntax diagrams, also known as railroad diagrams, from context-free grammars specified in EBNF. You can copy the SVG code or take screen shots.

You have to type in the grammar and it'll make the diagram.

For example, to create the first railroad diagram you show, you would use the code:

object ::= '{' ((string ':' value ) ( ',' string ':' value )*)? '}'

Then you could go on to define string and value using string ::= ... and value ::= ... The references are all shown.

Check out some of the example diagrams on the page. They have XML and even EBNF itself.

from Douglas Crockford
to Aleem B
date Tue, Apr 28, 2009 at 6:01 PM
subject Re: Railroad Diagrams on json.org

I drew them with Visio. Creative Docs.NET also works well.

--

Aleem B wrote:

Hello Douglas,

I thoroughly enjoy most things you put out there and the railroad diagrams on json.org are no different. I have been trying to look around for a tool that would generate diagrams nearly as eloquent but have had no luck:

Tool for generating railroad diagram used on json.org

Is there some tool you used to convert the BNF to these diagrams or were they hand crafted?

-- Aleem