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REXX is a high-level programming language created by IBM in 1979. It is easy to learn and use, has a simplified syntax, and no need for data type declarations. REXX is often used as a scripting language and can be used on any system. It has a free-form syntax, a small instruction set, and no data types. REXX is used as a glue language and is capable of interfacing with GUIs, databases, and web servers. It uses only character strings as data types, making it useful for parsing and processing text.
REXX stands for “extended restructured executor”. It is a programming language that was created to be easy to learn and use, contains aspects of a natural language, and relieves the programmer from having to worry about numerous details in computer operation. This is why it is referred to as a high-level programming language or scripting language. The language also boasts a number of additional features, such as a simplified and free-form syntax, a very small instruction set, and no need for data type declarations.
Originally created in 1979 by Michael Cowlishaw, who was working for IBM® at the time, it was initially nicknamed Rex, “a reformed performer” and the additional “X” was added later to avoid confusion with other products. Cowlishaw developed the language, in his spare time over the course of a couple of years, to serve as a scripting language that could be used on IBM® mainframe computers or any other system. IBM® released REXX as a product in 1982, due to growing popularity. Since then, the language has made its way onto every computing platform, including desktop personal computers and mobile devices.
As an interpreted language, REXX is often used as a scripting language, where the code is saved in a simple text file and then executed by the interpreter. Of course, the interpreter can also be used as a separate program, providing a command prompt for typing language syntax directly, making it useful for testing and other quick system commands and operations. REXX serves well as a glue language, therefore, as it is able to bundle functions from other programs into a single script. One of its greatest strengths is its design as a macro language. Program developers can simply add REXX support to their software so that macros can be written without having to program their own macro language into their software.
Another of REXX’s features is its free-form syntax, which makes the language similar to other scripting languages, such as Perl. With this capability, using the language becomes easier as placement requirements such as indentation and newline characters are less stringent. Also, the entire syntax used in the language is just 23 specific statements. This small instruction set, with its own operands, is capable of interfacing with just about anything, including graphical user interfaces (GUIs), databases, and web servers. For this reason, REXX is sometimes used as a Common Gateway Interface (CGI) scripting language on web servers.
Another somewhat unique trait of the language is the lack of data types. REXX uses only character strings as data types. String meanings depend on its usage, and math can be done on any string that forms a valid number. This inherent ability to work with strings makes the language useful for parsing and processing text.
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