Learn MODULA with Real Code Examples

Modula was designed to improve upon Pascal by introducing modules for encapsulation.

Supports separate compilation of modules, enabling better code organization.

Strong typing and strict type checking reduce runtime errors.

Focuses on simplicity and clarity for teaching and systems programming.

Used historically for operating systems, embedded systems, and educational purposes.

Procedural programming with modular design

Strong type system with compile-time checking

Modules with defined interfaces and implementations

Control structures: IF, CASE, WHILE, FOR, REPEAT

Procedures and functions with parameter passing

Modules - encapsulate related procedures, types, and variables

Procedures - executable code blocks

Data types - strong typing with integer, real, boolean, arrays, records

Interfaces - specify what a module exports

Import statements - access other modules

main.mod - main program entry

module1.mod - first module implementation

module1.int - interface file for module1

module2.mod / module2.int - additional modules

libs/ - optional library modules

Define module interface with exported types and procedures

Implement module with code and private declarations

Import required modules in main program

Compile modules separately

Link compiled modules and run executable

Beginner: simple arithmetic and control flow programs

Intermediate: modular programs with multiple modules

Advanced: data structures using records and arrays

Expert: system programming or compiler construction

Auditor: formal verification and modular testing

Modula vs Pascal: Modula adds modules and separate compilation

Modula vs C: Modula enforces stronger typing and modularity

Modula vs Ada: Both support reliability; Ada is more feature-rich

Modula vs Java: Modula procedural, Java object-oriented

Modula vs Python: Python is dynamic, Modula is strongly typed and compiled

1975 – Modula-1 initial design

1978 – Modula-2 development

1980s – Modula-2 widespread academic use

1988 – Modula-3 design

1990s–2000s – Modula used in system and educational projects

Module - encapsulates types, procedures, and variables

Interface - defines what a module exports

Implementation - actual code of a module

Procedure - block of executable code

Strong typing - compile-time type checking