HP 3000 Manuals HP 3000 Manuals
Dynamic Loading of 3GLObjects in ALLBASE/4GL (B.03)
by Michael Pardy
Application Support Division/STC
This version of ALLBASE/4GL (B.03) gives software developers three extra
features that further increase the speed with which they can create,
maintain, and execute applications. The new features are dynamic loading
of 3GL objects, field-sensitive recall of item names, and improved access
to the catalog of application items.
PRODUCT OVERVIEW
ALLBASE/4GL is a highly productive fourth generation language that
enables developers to create sophisticated applications that are easy for
end users to learn and operate. Developers can use ALLBASE/4GL to create
applications that manage and store data in KSAM files, serial files,
ALLBASE/SQL tables, and HP TurboIMAGE data sets. ALLBASE/4GL includes a
Dictionary, Module Builder, Screen Painter, Logic Facility, Report
Writer, and Administration facility. These features are controlled via
screen forms, menu items, and function keys. They are easy to use and
automate many conventional tasks.
The Dictionary and Module Builder provide good examples of how facilities
in ALLBASE/4GL are easy to use, as well as productive. The dictionary in
ALLBASE/4GL stores all application elements such as field descriptions,
screen messages, record layouts, etc. in a central location. Any
changes made to dictionary definitions are propagated throughout the
application's screens and logic at the press of a key. The Module
Builder can use the definitions of HP TurboIMAGE data sets, SQL tables,
and files to automatically create a module. A module includes a data
entry screen and the logic necessary to add, delete, modify, and view
records in a file or SQL database. To create a program with the same
functionality using a 3GL would take hours, possibly days. With the
Module Builder, the developer simply enters the name of the existing
table and presses a function key. Using the Screen Painter, Logic
Facility, and Report Writer, developers can extend modules to create
applications as complex as necessary to satisfy a client's needs.
However, even the most complex application will be easy to use because
the creation of menu items, context-sensitive help screens, and function
keys, are all supported by ALLBASE/4GL.
Dynamic loading
A new command has been introduced to provide dynamic loading of Native
Mode routines written in the C programming language. The command is
called CALL. It allows developers to utilize existing code libraries and
develop applications faster. The CALL command executes routines in the
same process as ALLBASE/4GL whereas the EXTERNAL command starts up
completed programs as another process. The CALL command enables the
routine to become an active part of the ALLBASE/4GL process, providing
maximum flexibility and high performance. With this enhancement,
ALLBASE/4GL becomes truly extensible. Developers can add their own
functionality to ALLBASE/4GL, build up libraries of object code, and
create a development system geared toward maximum productivity.
Name recall and Catalog access
Even developers with consistent naming conventions are sometimes
frustrated by not being able to remember the correct syntax for the name
of some function, record, scratch-pad or other item. Two enhancements
included in Release B.03 address this problem. Name recall is a
context-sensitive recall facility that allows developers to scroll
through the names of items that could be entered into the active field.
At any field on a screen form, developers can simply press the function
key labeled Name Recall and tab through all item names that may be
entered in that field. Furthermore, if the developer enters the first
few letters of an item's name, name completion is attempted before
tabbing is allowed. Catalog Display is the name for a new function key
that can be accessed from any screen in the ALLBASE/4GL Developer Pack.
Pressing this key displays either the Catalog index, or if the active
field is restricted to items of a single type, the names of all items of
this type will be displayed immediately. Upon leaving the catalog
display the user is returned to the original screen. This enhancement is
especially useful when the developer is creating a new item and wants to
ensure consistency with related items, or when the number of possible
items is too large to step through one by one.
Availability
ALLBASE/4GL is available in two versions. The Run-Time Environment (HP
30602A) includes everything needed to run (but not modify) a completed
ALLBASE/4GL application. The Developer Pack (HP 30601A) includes the
facilities for application development, plus facilities for running and
testing applications as an end-user. Application elements can be tested
individually, or a complete application can be run as if by the end user.
Step tracing, with trace log files, is always available. Both versions
of ALLBASE/4GL (Developer and Run-Time Environment) come complete with an
Administration application. This allows tailoring of screen appearance,
system-wide standards (such as date and time formats), and control of
end-user application security. With tools as sophisticated as
ALLBASE/4GL, maximum benefit can only be gained with training. For this
reason, the product includes a Self-Paced Training Guide, as well as
reference and administration manuals. Part numbers for additional
manuals are:
* HP ALLBASE/4GL Developer Administration Manual (P/N 30601-64001)
* HP ALLBASE/4GL Developer Self-Paced Training Guides (P/N
30601-64003)
* HP ALLBASE/4GL Developer Reference Manual (P/N 30601-64005), (2
volumes)
* HP ALLBASE/4GL Run-Time Administration Manual (P/N 30602-64001)
* HP ALLBASE/4GL Developer Manual Kit for MPE XL (P/N 30601K),
30601K), (Includes all manuals above.)