# Summary Tables

Containers and agents may display a summary table of their contents if their title bar is tall enough to accommodate it.

To define a Summary Table for a container, expand the container’s title bar and click on the container’s summary table button.

In the Summary Table popover, use the “+” button to add rows, the “-“ button to delete rows, and edit the row names and expressions as you prefer.

### Attributes and the Summary Table

The contents of the summary table are determined by the attribute `$TableExpression`, which should evaluate to a string using the vertical bar character "|” to separate columns. For example:

> `$Name+"|"+$AssignedTo`

will display the name of each note and the person to whom the note is assigned.

The table heading is taken from the attribute TableHeading; for example:

> `TASK|ASSIGNED TO`

Tinderbox displays one line for each child of the agent or container, until it runs out of space or lists each child.

If the table expression for a child note evaluates to the empty string "", that row of the table is skipped.

If the table expression for a child note evaluates to the string "-", a single hyphen, that row of the table is replaced by a horizontal rule.