Story environment guide

Isla story environment guide

Overview

This document covers the tools available to a programmer writing a story in Isla code. This includes the extra data types related to the story world, like room, and the automatically generated variables, like me.

This guide is written for experienced programmers who wish to play around with Isla. It is not intended for Isla's eventual target audience, young children.

Types

Pre-defined types

In the Isla language, a type is like a class that has only attributes. You can create an instance of a type and assign it to a variable:

palace is a room

This creates an object of type room that has some pre-defined attributes like summary and items and assigns this object to the variable palace. You can assign a value to an attribute:

palace summary is 'The floor is of marble.'

The pre-defined types that are accessible in the Isla story environment, and the attributes that are meaningful in the story environment:

• room
  • summary [string] A description of the room. This will be displayed when the player enters the room, or when they type look.
  • items [list] A list of items in the room. These are the items that the player can interact with when they are in the room. In the future, there will be built-in item types.
  • exit [room] A room that this room connects to. Because a room only has one exit attribute, rooms are connected in chains. So, to connect a chain leading from the palace to the garden to the road, you would write: palace exit is garden and garden exit is road.

Programmer-definable types

The Isla language supports the definition and instantiation of types by the programmer. See languageguide.md for more details.

Pre-defined variables

Some variables are pre-defined for the programmer. These variables can be manipulated when defining a story.

• my The variable defining the player object.
  • name [string] The player's name. Not currently used.
  • summary [string] A description of the player. Displayed when the player types, look at myself.
  • room [room] The room the player is currently in. This must be set in the Isla code to indicate which room the player starts in.
  • items [list] The items the player is carrying.

Programming a story in the Isla language

When you play your story, all variables pre-defined in the environment and all objects made from pre-defined types will be incorporated automatically into the story. Following is an outline of programming a story in the Isla language.

Set the attributes of the player

my name is 'Mary'
my summary is 'You are a young boy. You have no shoes on.'

The summary will be displayed if the player types look at myself.

Create the rooms in which the story will take place

hallway is a room
hallway summary is 'It is dark. You hear a girl crying.'

garden is a room
garden summary is 'You see a girl crying.'
hallway exit is garden

The summary will be displayed if the player types look. The player can move to another connected room by typing something like go into garden.

Set the room the player starts in

my room is hallway

Play your story