6.4 A strategy for programming

1.

Modelessness

• With few exceptions, a give action on the user's part should always have the same result, irrespective of past activities
• Long-term modes, such as doing word processing as opposed to graphics editing. In this sense, each application is a mode
• Short-term ``spring-loaded'' modes in which the user must constantly do something to maintain the mode.
• Alert modes
• Emulation of a familiar real-life situation that is itself modal
• Changing the attributes of something, but not its behavior
• Blocking most other normal operations to emphasize modality

2.

The event loop

• Applications are prepared for the user to do anything at any time

3.

Reversible actions

• Always provide a way out

4.

The screen

• The screen is the stage for human-computer interactions

5.

Plain language

• Communicate with the user in concise and simple forms