The basic actions and objects

This section is mainly for reference. It summarises the eight basic bug actions, and the properties of the objects used in the AI and PopBeast and Production systems handouts. You will need it before you try out the manual bug described in the following section, and before you start writing your own brains. Eden is not, by the way, limited to the objects listed below, and it is possible to create new types.

There are eight actions:

forward     back
right       left
grab        drop
use         wait

Forward and back move one square forward or back, unless the square being moved into is blocked, in which case nothing happens.

Right and left turn 90 degrees in the appropriate direction, but don't move forward or back.

Drop and grab pick up or put down an object. If the bug tries to grab an object but the object is ``too heavy'', nothing will happen; also nothing will happen if it is already carrying something. Dropping an object leaves it in the current square; if this is already occupied by another object (of whatever type) nothing happens, and the bug remains holding the object.

Waiting does nothing for a turn.

The effect of using an object depends on its type, so this is the next thing to look at, in the table below.

The table also indicates, in the Share column, what happens on moving into the same square as an object. A y in the Share column means that the bug can enter the same square as the object, n means it can't.

The Grab column indicates the effect of grabbing an object. y means that it can be picked up; n, that it can't.

The numbers refer to notes below.

1

Moving forward or back off the quicksand is OK; any other action will drown you.

2

You can only pass into a narrows if you are not holding anything.

3

Using food eats it.

4

Using a hammer only does something if you are facing a rock. The rock disappears, the hammer remains in your inventory.

5

Using a key only does something if you are facing a door. The door and key both disappear.

6

Using a coin only does something if you are facing a slot machine. The coin disappears, and a piece of food is dropped into a randomly chosen empty square nearby.

In this table, the ``narrows'' corresponds to a narrow gap, that you can only move through if not carrying anything.

Note that an unsuccessful action does not crash the system, it merely has no effect.