grammar WikiCreole
  rule Page
    Block*
  end
  rule Block
    Heading / Paragraph / List / Preformatted /  HorizontalLine / EmptyLine
  end
  rule EmptyLine
    Whitespace* LineEnd
  end
  rule HorizontalLine
    "----" "-"* Whitespace* LineEnd
  end
  rule Heading
    Heading3 / Heading2 / Heading1
  end
  rule Heading1
    '==' Whitespace* HeadingText Whitespace* '='* Whitespace* LineEnd
  end
  rule Heading2
    '===' Whitespace* HeadingText Whitespace* '='* Whitespace* LineEnd
  end
  rule Heading3
    '====' Whitespace* HeadingText Whitespace* '='* Whitespace* LineEnd
  end
  
  rule HeadingText
    TextPart+
  end
  
  rule Preformatted
    '{{{' Whitespace* LineEnd PreformattedLine* LineStart Whitespace* '}}}' Whitespace* LineEnd
  end
  rule PreformattedLine
    .* LineEnd
  end
  rule Paragraph
    TextLine+
  end
  rule TextLine
    !'==' TextPart+ LineEnd
  end

  rule TextPart
    PlaceHolder / Image / Link / BoldText / ItalicText / NormalText
  end
  rule ItalicText
    '//' TextPart+ '//'
  end
  rule BoldText
    '**' TextPart+ '**'
  end
  rule NormalText
    [^\n]+
  end
  rule PlaceHolder
    '<<' [0-9]+ '>>'
  end
  rule Image
    ImageWithAlt / ImageWithoutAlt
  end
  rule ImageWithAlt
    '{{' ImageAddress '|' '}}'
  end
  rule ImageWithoutAlt
    '{{' ImageAddress '}}'
  end
  rule ImageAddress
    URL / ImageFile / PageName
  end
  rule ImageFile
    .* '.' ImageFileExtension
  end
  rule ImageFileExtension
    'gif' / 'jpg' / 'jpeg' / 'png' / 'svg'
  end
 
  rule Link
    LinkWithoutText / LinkWithText
  end 
  rule LinkWithText
    '[[' LinkAddress '|' LinkText ']]'
  end
  rule LinkWithoutText
    '[[' LinkAddress ']]'
  end
  rule LinkAddress
    PageName / URL
  end
  rule URL
    URLProtocol ':' RestOfURL
  end
  rule URLProtocol
    'http' / 'https' / 'ftp' / 'mailto' / 'news' / 'irc'
  end
  rule RestOfURL
    .*  
  end
  rule PageName
    [a-zA-Z0-9.?!_ -]+
  end
  rule List
    FirstListElement ListElement*
  end
  rule FirstListElement
    FirstBullet / FirstNumber
  end
  rule FirstBulletElement
    '*' Whitespace TextPart*
  end
  rule FirstNumberElement
    '#' Whitespace TextPart*
  end
  rule BulletElement
    '*' Whitespace TextPart*
  end
  rule NumberElement
    '#' Whitespace TextPart*
  end
  rule FirstBullet
    '*'
  end
  rule FirstNumber
    '#'
  end
  
  rule LineEnd
    [\n] 
  end
  
  rule Whitespace
    [ \t]
  end
  
end