Because VT does not provide an easy way to determine when the host is finished sending data, tasks are recorded with an intermediate transient step between each settled task step.
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For example, when a task navigates between Step 1 and Step 2, an attempt is made to match the current screen to the recognition rule for Step 2. If that fails, then the navigation engine attempts to match the transient recognition rule, (which is always "true"), and then tries to recognize Step 2 again. This process provides the host with time to send more data, and is repeated until the recognition rule match is successful or a timeout occurs and the task fails. |
In VT, any key can be an AID key and, when pressed, keys are usually sent to the host immediately. To handle "non-standard" AID keys, when significant screen changes occur (during host interaction without an accompanying AID key), the last task input is used to transition between screens.
Synapta Services Builder for VT uses recognition rules not only to identify screens, but to determine when a screen is settled. Each recognition rule must be explicit enough to match the screen only after it is settled. You can refine screen recognition rules using VT-specific expressions to match the cursor position or the last data received from the host or with user fields.
For more information, see Recognition Rules for VT Hosts.
Fields are fixed regions on the screen with text and attributes associated with them. VT screens are, by nature, unformatted, and while individual characters on a screen may have attributes associated with them, there are no host fields. By default Task Builder creates a single unprotected host field for each screen, which encompasses the entire screen. This is used for both screen recognition and navigation to aid in discovering and placing data on a screen.
You can choose to have Task Builder automatically format the screens with user fields during recording. The resulting recorded screens contain one host field and any number of automatically created user fields, each line on the screen representing a field. These fields can be included in step recognition rules, or used as outputs to the current step or task, but they cannot be used as inputs. For information about automatically creating fields during recording, see Automatically Adding User Fields to VT Screens. You can also add user fields after recording.
