<![CDATA[<style><h1><font size="7">application development, 4GL, fourth generation language</font></h1>
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Technology
Speedware V7 is a complete application development suite for enterprise-scale business applications running on the HP e3000, HP-UX and Windows. It includes all of the necessary components to design, develop, test, and execute applications - all from within a single productive development and runtime environment.
The Speedware integrated development environment is composed of the following key components:
- Speedware Designer : The development tool
- Speedware/4GL : The run-time engine
- Utilities
- Makecat : The data dictionary (Catalog file) manager
- Makeprof : The user security (Profile file) manager
- Makeconf : The terminal and Printer definitions (Config file) manager
From Speedware Designer, developers can manage all application components, including the data dictionary (known as the CATALOG file), source code (SPEC file) and user security properties (PROFILE file). When these three files are combined, Speedware/4GL creates a compiled application file, known as the Z-file. To execute a Speedware application, simply point to this file.
Developers can also use Designer to load an existing database structure and design concepts, such as data-entry screens, data reports, and menu structures. Then, Designer generates all the necessary source code and compiled files to allow the application to run smoothly.
From a repository, Speedware Designer can generate several distinct application environments.
Speedware Designer is an interactive object-oriented CASE tool that manages the Speedware application development life cycle. It is a truly unique tool, as it generates all the source code required to begin developing an application. It generates the outline for all Speedware/4GL sections, allowing you to concentrate on your application business logic.
Using Designer, developers never need to use editors or external tools. Database structures can be loaded or designed and screen layouts, reports and menu structures can be devised - all from within the same user-friendly environment. When Designer builds the source files, it uses its object definitions to generate all of the source files and code required to run an application.
Designer uses a repository, known as a “design”, to hold all objects created, used and updated for your applications.
Designer is multi-database, which means that one design can store data objects for one or more physical databases and any number of files. Designer is also multi-user, allowing developers in a project team to concurrently access and update the same design.
A typical application development life cycle using Designer could be summarized as follows:
- Load/Define database structure (performed only once)
- Create/refine screen, report, batch and menu sections
- Add/refine business logic
- Generate and test application
Speedware/4GL consists of a high-level scripting language; a compiler to compile the source code into pseudo-code; and a run-time engine to executes it. The compiler and run-time engines exist on the HP e3000, HP 9000 and Windows platforms. The language is platform and database independent.
In Speedware V7, source files are known as specification files (SPEC files). The SPEC file is a single file, which contains the source code necessary to represent all components of an application.
Anatomy of the Language
The Speedware/4GL language is easy to learn and use, since it follows specific syntax rules. A Speedware/4GL statement consists of a verb with its object, options and parameters. It starts with a verb and ends with a semi-colon. The syntax of a statement follows a standard pattern:
VERB { object [OPTION (PARAMETER ,...)] ...} ,... ;
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A verb is a term that specifies an action, for example: ACCEPT, COMMAND, LIST, PRINT or TAKE. The object of a verb is the data item, variable, expression, string or numeric value, upon which the verb operates. Options are features that may be specified to modify the way a verb operates on the object. Parameters are the values appropriate to each option.
Structure of a Source File
A Speedware source file is a text file containing the Speedware/4GL code for an application. The source file consists of sections, each having a principal function in the application, such as screen-, report- or menu-handling.
A section begins with a section name. The section statements begin with file, variable and environment declarations, followed by statements that specify actions. Each section type allows a different set of actions; for example, Menu sections create menu branches and function keys, while Screen sections create data-entry fields. Each section ends with the EXIT keyword. A simple example Menu section containing two menu branches and a function key appears below:
MENU-Reports:
SET WINDOW(ROW=4, COLUMN=10, HEIGHT=9, WIDTH=20);
SET TITLE("Reports Menu");
BRANCH "Customer Listing" DO REPORT-CUST-LIST;
BRANCH "Orders by Customer" DO REPORT-ORDERS-BY-CUST;
FNCKEY "Calendar" KEY(NUM=7) DO MENU-CALENDAR;
AT HELP DO TEXT-MenuReportsHelp;
EXIT;
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Compiling and Executing an Application
An application may be compiled and executed either within Designer or outside of it. If executing from Designer, the GO command is used to ensure that the source files are up-to-date and compiles them to run the application.
Speedware/4GL uses the SPEC file (source code), CATALOG file (data dictionary) and PROFILE (user security) file as source and combines them to build a compilation file. Similarly to Sun’s Java, the Speedware/4GL code is compiled into pseudo-code, which in turn is interpreted by the Speedware/4GL engine.
Speedware/4GL delivers great performance. Its engine has been proven for the past several years and has been optimized to deliver the highest efficiency in code execution.
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