Modula-2

Modula-2 is a modular, general-purpose computer programming language developed in the late 1970s by Niklaus Wirth, the creator of Pascal. It was designed as a successor to Pascal, incorporating improvements based on experience with that language and influenced by the need for modular programming in increasingly complex software projects.

Modula-2's key features include strong type checking, separate compilation of modules with explicit import/export declarations, and low-level access to machine resources. These features made it suitable for systems programming, embedded systems, and other applications where control over hardware is essential.

A core concept of Modula-2 is the module. Modules serve as independent compilation units that encapsulate data and procedures. Each module can explicitly export certain elements (variables, types, procedures) for use by other modules, while keeping other elements private. This promotes code reuse, reduces dependencies between different parts of a program, and enhances maintainability. The IMPORT statement allows a module to access exported elements from other modules.

Modula-2 offers features for low-level programming, including address arithmetic, bit manipulation, and direct access to hardware. It provides mechanisms for exception handling through the use of TRY and EXCEPT blocks.

The language includes built-in support for concurrent programming through the use of coroutines, which are lightweight threads of execution. This facilitates the development of programs that can perform multiple tasks concurrently.

While Modula-2 was influential in the development of subsequent programming languages, such as Oberon, it did not achieve widespread commercial adoption compared to languages like C and C++. Its main strengths lie in its clear syntax, support for modularity, and features for systems programming. It remains relevant in certain niche areas and continues to be studied as an example of a well-structured and influential programming language.