Heirarchical files

The actual MSE data is stored in heirarchical data files, these are usually files with no extension.
For example <tt>set</tt> or <tt>locale</tt>.
These are just ordinary text files, but they use an UTF-8 encoding, that means you need to use an editor that supports UTF-8.
Most modern editors support UTF-8, Notepad does on Windows XP.

--Syntax--
The files use a heirarchical structure and are made up of keys and values.
A value can be either a simple text string:
>game: magic
Or a block containing more keys and values:
>card:
>	name: My Card
>	type: Creature

Indentation is used to find out what belongs to what block. Indentation must be exactly one <tt>TAB</tt> per level, spaces are not allowed.

When the value is longer then a single line it can be written indented on the following lines:
>text:
>	T: Draw a card
>	WW: Gain 1 life

--Order--

Usually the order in which keys appear in a file doesn't matter.
However some keys, like @mse version@ and @type@ must come first because they influence how the following keys are interpreted.

--Includes--

A heirachical file can contain a reference to another file:
>>>include file: <em>filename</em>
Where filename must be an absolute [[type:filename]].

That file is included literally into the current one; except for indentation, the included file never escapes from the level the 'include file' line is on.

--Example--
For example, a [[type:set]] might look like this:
>game: magic
>style: new
>card:
>	name: My Card
>	type: Creature
>card:
>	name: Another card
