EBNF Parser & Syntax Diagram Renderer

The EBNF Parser & Syntax Diagram Renderer can be used stand-alone or as Dokuwiki-Plugin.

• https://www.dokuwiki.org/plugin:ebnf
• Requirements: Make sure to have the GD library ready

<ebnf> "EBNF defined in itself" {
syntax     = [ title ] "{" { production } "}" [ comment ].
production = identifier "=" expression ( "." | ";" ) .
expression = term { "|" term } .
term       = factor { factor } .
factor     = identifier
           | literal
           | "[" expression "]"
           | "(" expression ")"
           | "{" expression "}" .
identifier = character { character } .
title      = literal .
comment    = literal .
literal    = "'" character { character } "'"
           | '"' character { character } '"' .
}</ebnf>

The script is also available as stand-alone version under: your_dokuwiki/lib/plugins/ebnf/ebnf.php

.../ebnf.php?syntax="EBNF"{ hello = "Hello World". }"Some additional Comments"

Note: The stand-alone script supports also XML output

.../ebnf.php?syntax={ hello = "EBNF Hello World in XML". }&format=xml

• See examples: EBNF Examples
• EBNF
• Wirth_syntax_notation

• Ellipse … for enumerations. E.g. digits:
  • temp hack in v0.2: function render_node($node, $lefttoright)

     ...
        else {
          if ($text!="...")
    	      rr($im, UNIT, 0, $w-UNIT-1, $h-1, UNIT/2, $black);
          imagestring($im, FONT, 2*UNIT, ($h-imagefontheight(FONT))/2, 
            $text, $text!="..."?$blue:$black);
        } ...

• Other fonts
• Configurable dimensions
• escape-chars and or unicode in terminals
• Adding Regexp beside terminal and identifiers
• using a lightweight syntaxtree instead DOM
• using some standard parsing mechanism
• support for comments & special-sequences ? … ?
• http://www.cs.man.ac.uk/~pjj/bnf/ebnf.html
• replace antialias function