A prolog example to determine who needs to die before somebody can become king.
Use the [online prolog intepreter] (http://swish.swi-prolog.org/) for your queries. Just copy the content of the becomeKing Prolog script into the editor.
To find out how Robbert becomes king use this query:
becomeKing(robbert,X)
For easier understanding on how the people in this example are related, please see the family tee below. (Or directly in the Overview.txt)
XX X X+
+XXXX XXXXX XXX|
| XX XXX XXX XXX |
| XXX XXX XX XXX |
| XXX XXX |
| |
| King Martin (m) |
| |
+--------------+------------+
|
+---------------------------------------------------------------------------+
| | |
| | |
+------------+------------+ +--------------+-------------+ +-------------+-------------+
| | | | | |
| John (m) | | Fiona (f) | | Robbert (m) |
| | | | | |
+------------+------------+ +--------------+-------------+ +-------------+-------------+
| | |
+------------------+---+--------------+ +------+-----------+ |
| | | | | |
+-----+-----+ +------+-------+ +-----+-----+ +-----+-----+ +-----+-----+ +-----+------+
| | | | | | | | | | | |
| Mary (f) | | Jeffrey (m) | | Tim (m) | | Nick (m) | | Ana (f) | | Tom (m) |
| | | | | | | | | | | |
+-----------+ +--------------+ +-----------+ +-----------+ +-----+-----+ +------------+
|
|
+-----+-----+
| |
| Peter (m) |
| |
+-----------+
~~~
The tree was created with [asciiflow](http://asciiflow.com).
## Rules to become king
The basis on how to become king were taken from [here](http://www.cgpgrey.com/blog/how-to-become-the-british-monarch).