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:
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 objects such as maps will become obvious when it comes to maintaining existing Natural applications.
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.
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 a comprehensive description of the full range of possibilities provided by the Natural map editor (character-user-interface version), see Map Editor Tutorial.
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.
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.
