Introduction

This is an introductory text to XML, the extensible markup language used for our texts.

There is also the ​W3C Recommendation.

Basic facts about XML

• An XML document is a plain text file, preferably in Unicode encoding
• The structure is made up out of nested elements, like a matroshka.

   <root>
      <nestedElement>With content</nestedElement>
      <anotherElement with="attribute" another='one'>Elements can have attributes </emptyTag>, as well</anotherElement>
      <!-- I am a comment <hidden>everything here is</hidden> ignored -->
      <question>did we already talk about &amp; entities?</question>
   </root>
  

  As with a matroshka, also in XML, you cannot put half a puppet into the bigger puppet: they have to be properly nested.
• Some characters are forbidden, they have to be escaped by entity references:
  • <: <
  • >: >
  • &: &
  • ": " (To a lesser extent, namely only in attribute values)
  • ': ' (To a lesser extent, namely only in attribute values)