## Definition File

ABLE uses a specially designed file called a definition file to define the content of text files. Fields in text files can be delimited by spaces or commas. Each record in the file describes one field, and each record contains three values:

1. Field name
2. Data type, must be one of:
   - categorical is text or character data representing a finite set of names
   - continuous is integer or decimal represented as text
   - discrete is integer or decimal represented as text but with a finite set of values
3. Field usage, must be one of these special values:
   - input identifies the field as input
   - ignore identifies a field as one to be ignored by translation filters; the field data enters the filter bean, but is not part of its output.
   - output identifies the field as a target value for beans and agents that use supervised learning such as the AbleNeuralPredictionAgent and AbleNeuralClassificationAgents

Create definition files with your favorite editor in text format. Here is the animal.dfn file as an example of a definition file used by the AbleNeuralClassificationAgent:

>     eats_grass? categorical input
>     flies?      categorical input
>     swims?      categorical input
>     type        categorical input
>     color       categorical input
>     legs        discrete    input
>     weight      continuous  input
>     animal      categorical output