Top Hat

Use import statements to import names from libraries.

Import Names

Access the value bound to a name by using the name in an expression.

Represent numbers in code using numeric literals.

Write pieces of code that compute a value.

Compute numeric values by composing expressions with arithmetic operators.

Compare two values to determine whether one is equal to, less than, or greater than the other.

Ask a function to do its computation and to return the result.

Call a function to output a given textual or graphical value.

Introduce a name for something, so you can then refer to that thing by using that name.

Create functions that can be called to do specific computations.

Specify which types of values function parameters can accept, and which type of values a function will return.

Specify assertions to check that the values a function receives are acceptable.

Exploit the freedom how exactly you nest expressions thanks to associative operators and functions.

Change code to make it more readable, without changing what it does.

Use predefined colors like red, green, and blue.

Create any color you like by describing it as a point in some color space.

Create primitive graphics like rectangles, ellipses, triangles, circular sectors, and texts.

Create a rotated version of a given graphic.

Create a composite graphic from two given graphics.