# Expressions

A Storyspace expression represents a value – something that could potentially be stored in an attribute. The following are expressions:

- 42
- "Now is the winter of our discontent"
- (7+6)/5
- $Price

Most actions simply store the result of an expression in an attribute. For example

`$Price=1.95`

sets the value of the attribute `Price` in the current note, and

`$Color="red"`

turns the current note red.

In addition to their use in actions, expressions have a variety of uses in Storyspace:

- link guard fields and `$Requirements` are expressions; when true, the link can be followed or the note can be visited.
- `$DisplayExpression` is an expression; if `$DisplayExpression` is not empty, then the value of `$DisplayName`, ands the title displayed for the note in maps and other views, is the result of evaluating `$DisplayExpression`.
- The value of `$HoverExpression`, if `$HoverExpression` is not empty, appears while the cursor hovers over a note in map or or outline view.
- The value of `$TableExpression` determines what appears in a note’s summary table.