PEARL, or Process and experiment automation realtime language, is a
computer
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...
programming language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language.
The description of a programming ...
designed for multitasking and
real-time
Real-time or real time describes various operations in computing or other processes that must guarantee response times within a specified time (deadline), usually a relatively short time. A real-time process is generally one that happens in defined ...
programming. Being a
high-level language, it is fairly
cross-platform
In computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several computing platforms. Some cross-platform software ...
. Since 1977, the language has been going under several standardization steps by the
Deutsches Institut für Normung
' (DIN; in English, the German Institute for Standardisation Registered Association) is the German national organization for standardization and is the German ISO member body. DIN is a German Registered Association ('' e.V.'') headquartered ...
. The current version is PEARL-90, which was standardized in 1998 as DIN 66253-2.
Features
PEARL supports both
fixed-point and
floating-point
In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can ...
numeric values, character and character
string data as well as bit values. It also provides facilities for structures and multi-dimensional
arrays. Both typed and untyped pointers are also supported, along with typecasting.
PEARL is a higher programming language, which allows a comfortable, secure and almost processor independent programming of multitasking and realtime problems and has been standardized since 1977 at various stages of its development, the last time 1998 as PEARL-90 (DIN 66253-2 1998, Berlin, Beuth-Verlag, 1998).
Besides the simple possibility to map process technical problems, an important principle at the development of PEARL was the easy learning by the programmer.
All basic data types and language structures of other procedural programming languages exist in PEARL. In addition PEARL offers comfortable language elements for the handling of multitasking- and realtime tasks.
Like most other high-level languages, PEARL supports
procedures and functions, and passing parameters to these can be done by value or by reference (via
pointers).
Example
MODULE (HELLOWORLD);
SYSTEM;
TERMINAL:DIS<->SDVLS(2);
PROBLEM;
SPC TERMINAL DATION INOUT ALPHIC DIM(,) TFU MAX FORWARD CONTROL (ALL);
MAIN:TASK;
OPEN TERMINAL;
PUT 'Hello World!' TO TERMINAL;
CLOSE TERMINAL;
END;
MODEND;
External links
Process and Experiment Automation Realtime Language PEARL 90 - Language Report(PDF)
Procedural programming languages
Statically typed programming languages
Real-time computing
Programming languages created in 1977
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