Chameleon Window Layout

Chameleon consists of an editor window and a debugging window

Uncertain expressions and cards

One important feature of Chameleon is to show all the 'uncertain' expressions as a list of cards. Clicking on a card activates it. The active card is black, inactive ones are white. This feature can be enabled by clicking the chevron button or pressing tab key.

Possible types

An uncertain expression is an expression can be typed in two different ways . We refer to them as possible type 1 and possible type 2.

Highlights

Highlights are fragments of code with colored background . Highlights can be either blue or orange . They are the parts of the source code from which Chameleon deduces the possible types.

Highlights (color-switching)

Highlights switch color (blue to orange or vice versa) when the active card (or deduction step ) changes. Notice the highlight of y on the second line changes color when activating card y .

Deduction step (UI)

Deduction step is another important feature of Chameleon. A deduction step is displayed as an overlay widget in the editor window. It comprises a pair of highlights (one blue and one orange) outlined in black, and a text box showing how the two are related to one another. Deduction step can be enabled by clicking the second chevron button or pressing the tab key.

Deduction step (control)

Each card contains one or more step buttons . Clicking on a step button activates the step. Each card can associate with 0 or 1 active step and any number of inactive steps.

Deduction step (example)

When activating a step, some highlights switch color. The message in the text box changes as well. For example, activating step 2 , step 3 , and step 4 result in the editor window showing different deduction steps.