Snapdown

In this example, we have two variables: i points to the value 5, and s points to the value "abc".

In this example, f points to a MyFloat object with the value 5.0, s points to a MyString object with the value "abc".

Here we have a variable lst pointing to an ArrayList with three fields representing the elements, and a fourth field representing the length. (Note that Java, or another programming language, may not actually represent the list this way -- Snapdown is purely a drawing tool that can get us any representation we wish.)

This example shows a function main() with local variables s and season2.

In this example, we have a MyLine with three fields. The start and end fields are best expressed as pairs of numbers. We can use backticks `` to display the text (10, 10) verbatim. We can represent the GREEN color in a similar fashion.

In this example, we have two maps, each with a single key, and both with the same single value.

Note the double-lined arrows and bubbles indicating immutable references and objects.

In this example, the variable t is an alias of s, and season2 is an (immutable) alias of the season field of s.

References are considered unnamed if they start with a hash symbol, #. In this example, the #sem name is never actually drawn in the diagram, but we can use it inside the two Course objects to avoid deeper nesting, and to avoid repeating the same Semester object twice.

Use an x in the middle of an arrow to indicate that an arrow should be crossed out. Arrows are typically crossed out to indicate reassignment.