> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Predefined variables

> Predefined variables in the FlexiLayout language: IsNull, IsSuspicious, OutputRegion, OutputInstances, and OutputTable for Region Expression sections.

The FlexiLayout language provides the following predefined variables. Their values report whether a block was found or detected reliably and define the region of a found block.

## Region Expression variables

Each row lists a variable and how it is used in the **Region Expression** section.

| Name              | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `IsNull`          | Variable of type `Logic`. Used in the **Region Expression** section. The value of the variable determines whether the block has been found. The `IsNull` variable is pre-initialized with the value **False**, which means that the block has been found. To tell FlexiLayout Studio that the block has not been found, set the `IsNull` variable to **True**. Used for blocks of all types.                                                                              |
| `IsSuspicious`    | A variable of type `Logic` used in the **Region Expression** section. Its value indicates whether the block has been detected reliably. The `IsSuspicious` variable is pre-initialized with the value **False**, which means that the block has been detected. To tell FlexiLayout Studio that the block has been detected unreliably, set the value of the `IsSuspicious` variable to **True**. Used for blocks of all types.                                            |
| `OutputInstances` | Variable used in the **Region Expression** section for blocks of all types for which **Has repeating instances** is enabled. For non-table blocks, the type of the variable is `HypothesisInstances`. For table blocks, the type of the variable is `TableHypothesisInstances`. The value of the variable defines the detected region of the block. The region of a block built from the instances of the elements and subelements of a repeating group is discontinuous. |
| `OutputRegion`    | Variable of type `Region`. Used in the **Region Expression** section. The value of the variable determines the region of the block. Used for blocks of all types except table blocks.                                                                                                                                                                                                                                                                                     |
| `OutputTable`     | Variable of type `TableHypothesis`. Used in the **Region Expression** section. The value of the variable is used to initialize the region and the contents of a block on the basis of a specific table element. Used only for table blocks.                                                                                                                                                                                                                               |