OpenEdge Advanced Business Language, or OpenEdge ABL for short, is a business application development language created and maintained by Progress Software Corporation. The language, typically classified as a fourth-generation programming language, uses an English-like syntax to simplify software development. The language was called PROGRESS or Progress 4GL up until version 9, but in 2006 PSC changed the name to OpenEdge Advanced Business Language in order to overcome a presumed industry perception that 4GLs were less capable than other languages. A subset of the language, called SpeedScript, is used in the development of web applications. OpenEdge ABL helps developers to develop applications optionally using its own integrated relational database and programming tool. These applications are portable across computing systems and allow access to various popular data sources without having to learn the underlying data access methods. This means that the end-user of these products can be unaware of the underlying architecture. By combining a fourth generation language and relational database, OpenEdge ABL allows the use of the Rapid Application Development model for developing software. A programmer and even end users can do rapid prototyping using the integrated and GUI tools of the development environment.
History
The original Progress 4GL was designed as an architecture independent language and integrated database system that could be used by non-experts to develop business applications by people who were not computer scientists but were knowledgeable in their business domain. At the time, business applications were often written in COBOL and sometimes in C. When the IBM PC became popular, it developed a need for business software that could be used on those and other inexpensive computers. The Progress system was created to be used on both IBM PC machines running DOS and on a variety of computers that could run UNIX.
Syntax and semantics
Progress ABL is a strongly typed, late-bound, English-like programming language. Although initially designed as a procedural language, starting with version 10.1 it was enhanced with object-oriented grammar elements, which can be mixed with the original procedural style. A block of code may have a transaction scoped to it, in which case database changes will be committed when it completes. An error raised within such a block will undo these changes. These defaults may be overridden by the programmer. Simple programs run without a Graphical User Interface, but there is syntax to create one programmatically; or programmers can use the provided tools to build one.
Examples
Hello World
The following ABL code creates a window with the text "Hello, World!" and a button labelled "OK". DEFINE VARIABLE w AS HANDLE NO-UNDO. CREATE WINDOW w ASSIGN WIDTH = 50 HEIGHT = 5 MESSAGE-AREA = FALSE STATUS-AREA = FALSE. CURRENT-WINDOW = w. DEFINE BUTTON btnOK LABEL "OK" SIZE 12 BY 1.2. FORM "Hello World!" VIEW-AS TEXT AT COL 20 ROW 2 btnOK AT COL 20 ROW 4 WITH FRAME f SIZE 50 BY 5 NO-BOX THREE-D. VIEW FRAME f. ENABLE btnOK WITH FRAME f. WAIT-FOR "CHOOSE" OF btnOK. DELETE OBJECT w.
A message-box can be used to achieve the same effect: MESSAGE "Hello World!" VIEW-AS ALERT-BOX INFO BUTTONS OK.
Also, you can use ERROR and WARNING instead of INFO to change the message icons. The simplest "Hello, World" program, though, is this: DISPLAY "Hello World!".
