Maps

As an alternative to specifying screen layouts dynamically, the INPUT statement offers the possibility to use predefined map layouts which makes use of the Natural object type "map".

This document covers the following topics:

Benefits of Using Maps

Using predefined map layouts rather than dynamic screen-layout specifications offers various advantages such as:

  • Clearly structured applications as a result of a consequent separation of program logic and display logic.

  • Map layout modifications possible without making changes to the main programs.

  • The language of an applications's user interface can be easily adapted for internationalization or localization.

The benefit of using programming objects such as maps will become obvious when it comes to maintaining existing Natural applications.

Types of Maps

Maps (screen layouts) are those parts of an application which the users see on their screens.

The following types of maps exist:

  • Input Map
    The dialog with the user is carried out via input maps.

  • Output Map
    If an application produces any output report, this report can be displayed on the screen by using an output map.

  • Help Map
    Help maps are, in principle, like any other maps, but when they are assigned as help, additional checks are performed to ensure their usability for help purpose.

The object type "map" comprises

  • the map body which defines the screen layout and

  • an associated parameter data area (PDA) which, as a sort of interface, contains data definitions such as name, format, length of each field presented on a specific map.

Related Topics:

  • For information on selection boxes that can be attached to input fields, see SB - Selection Box in the INPUT statement documentation and SB - Selection Box in the Parameter Reference.

  • For information on split screen maps where the upper portion may be used as an output map and the lower portion as an input map, see Split-Screen Feature in the INPUT statement documentation.

Creating Maps

Maps and help map layouts are created and edited in the map editor.

The appropriate local data area (LDA) is created and maintained in the data area editor.

Depending on the platform on which Natural is installed, these editors have either a character user interface or a graphical user interface.

Related Topics:

  • For information on using the data area editor, see Data Area Editor in the platform-specific Editors documentation.

  • For information on using the map editor, see Map Editor in the platform-specific Editors documentation.

  • For information on input processing using screen layouts specified dynamically, see Syntax 1 - Dynamic Screen Layout Specification in the INPUT statement documentation.

  • For information on input processing using a map layout created with the map editor, see Syntax 2 - Using Predefined Map Layout in the INPUT statement documentation.

Starting/Stopping Map Processing

An input map is invoked with an INPUT USING MAP statement.

An output map is invoked with a WRITE USING MAP statement.

Processing of a map can be stopped with an ESCAPE ROUTINE statement in a processing rule.