Programming Language for Business
PL/B is a modern business-oriented language, used throughout
the world, that is simple to learn but capable of performing complex
applications such as editors, data encryption programs and even PL/B compilers.
Portions of the following paragraphs concerning the origin and spirit of PL/B are drawn
from the two publications. Additional information can be found on the WEB at X3J15 - PL/B Programming Language.
ANSI Standard X3.238-1994, Rationale for Programming Language PL/B ©1994 American
National Standards Institute, New York, New York
The DATABUS Programming Language, by Dan Felder and Don Wills ©1992 Software Science
PL/B is a modern business-oriented language that is used throughout the world by a wide
variety of programmers. PL/B was conceived as a small, easy-to-learn language oriented
toward data entry applications. The first computers to run this language were built by
Datapoint Corporation, and typically came configured with 4k to 16k of RAM, contained 12
line by 80 column displays, and a typewriter-like keyboard that contained a numeric pad.
Because COBOL and other contemporary languages could not deal with the display and
keyboard, and because the languages probably would not fit in the available memory,
Datapoint invented DATABUS®, its proprietary version of the PL/B programming language.
From these humble beginnings, PL/B has grown to be a robust and full-featured language.
It is used today on micro, mini and mainframe computers. The success of PL/B is reflected
by the number of compilers available. There are currently at least a dozen companies
actively marketing independently developed PL/B compilers. These compilers run on a wide
variety of machines and operating systems, thus freeing PL/B from its proprietary roots.
The Accredited Standards Committee - X3J15 Technical Committee came about because of the
significant investments in (and loyalty to) the PL/B language. These investments are in
literally millions of lines of existing PL/B code in use at tens of thousands of
companies. PL/B is a mature, robust, and full-featured business applications programming
language used by many organizations, large and small. X3J15 named the ANSI Standard
language specification PL/B (Programming Language for Business), so as not to infringe on
the older proprietary name of DATABUS from Datapoint Corporation.
PL/B was originally used for data capture applications. While the language has outgrown
those roots, it has kept an emphasis on interactive I/O and file access methods. The ease
of control and powerful functions that PL/B offers for interactive terminals are
unparalleled. The file I/O functions grew quickly from the original simple sequential
access to a complete set of functions for manipulating files and organizing the data in
PL/B has many strong points. It is a strongly typed language that does not contain
pointer variables or allow structure overlays. This has saved countless debugging hours,
because variables can not be accidentally modified by errant program actions. The fact
that the language is similar to English makes maintenance much easier to accomplish. Both
the "big picture" and specific details of a program can be gleaned in minutes.
Because of its roots on early desktop computers, the keyboard and screen display
operations of PL/B are far superior to those of COBOL, C and other well-known languages.
PL/B programmers become spoiled by these and other features, and when forced to program in
other languages, do so at a much less productive level.
The nature of PL/B has also been shaped by its traditional implementation as an
interpretive language. For example, several properties of the language are structured
around the source language instructions. Nowhere is this more obvious than in the FILEPI
instruction, where files are locked for a number of source code language instructions.
Much of the unique spirit of PL/B is seen in the source code files. The combination of the
line oriented nature of the language and the free form comment fields, when used
effectively, can lead to highly readable and well documented programs. The custom of using
the comment field on each line to maintain a running commentary on the program operation
can lead to very readable programs that are highly maintainable.
There are other elements that make up the unique style and flavor of PL/B, things like:
the unusual nature of the character variables, the lack of reserved words, that all
arithmetic is done with decimal numbers, and the power that comes from the program
maintaining several indices on a data file separately.
Most of the facilities in PL/B are aimed at letting a programmer producing data
processing applications get the job done as quickly and easily as possible. Yet, PL/B is
not limited to data processing by any means. While PL/B makes it easy to perform simple
tasks, it is fully capable of performing extremely complex chores. Applications as diverse
as editors, data encryption programs, and even PL/B compilers have been written in PL/B.
So, while PL/B aims to be easy to use, it is by no means a "special purpose" or
Infopro decided early in its life to standardize application development and tool
development in the PL/B language. Our staff was completely conversant with other ANSI
Standard languages (e.g. COBOL, C, FORTRAN, Dartmouth BASIC) but found that none were able
to provide as high a level of vendor independence, portability, and productivity as PL/B
for programming business applications. COBOL was portable primarily within batch
environments. FORTRAN and C did not have the necessary portable file structures and
interactive support which PL/B does so well.
Remember CINCOM's TOTAL database, Oracle's SQL*Calc, Software AG's NATURAL, Ashton
Tate's DBASE? Database systems and proprietary languages gain and lose favor as do
corporate marketing budgets and fads. But ANSI languages persevere. Why? Because they
provide portability and stability from many vendors. ANSI standards are developed and
controlled through public deliberative processes. If Microsoft decides that a near future
release of its recently acquired Foxpro product will be the last (see speculation in
February 19, 1996 issue of Information Week), users will be forced to change languages
(Microsoft hopes to Visual Basic). No vendor can unilaterally decide the fate or set the
direction of an ANSI standard language.
Having competition in the marketplace for compilers of the PL/B language brings
additional benefits. Costs are competitive. A number of compiler companies do not charge
for run-time licenses. Some compiler companies compile directly to object code, while
other vendors compile to portable interpreted pseudo-code. Most of the PL/B vendors now
distinguish themselves by cost, speed, portability, interactive debugging tools, and
extensions to the language (such as the new crop of GUI interface statements). The best of
the language extensions will be considered for inclusion in future revisions to the PL/B
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