Pascal is a procedural programming language designed in 1968-1969 and published in 1970 by Niklaus Wirth as a small, efficient language intended to encourage good programming practices using structured programming and data structuring.
Pascal Anti-Patterns Overview
Pascal, despite being designed to encourage good programming practices, has several common anti-patterns that can lead to maintainability problems and bugs. Here are the most important anti-patterns to avoid when writing Pascal code.
Using GOTO Statements
Avoid using GOTO
statements, which make code difficult to understand and maintain. Use structured control flow constructs like for
, while
, repeat-until
, and if-then-else
instead.
Not Using Strong Typing
Leverage Pascal’s strong typing system rather than using variant records or other techniques that circumvent type safety. In modern Object Pascal, use interfaces, classes, or generics for type-safe polymorphism.
Using Global Variables
Avoid using global variables, which create hidden dependencies and make code harder to understand, test, and maintain. Pass data explicitly through parameters and return values.
Not Using Proper Error Handling
Use proper error handling with try-except-finally
blocks (in modern Pascal) to handle exceptions and ensure resources are properly cleaned up, even when errors occur.
Using Magic Numbers
Avoid using magic numbers (hardcoded numeric literals) in your code. Use named constants to make your code more readable and maintainable.
Not Using Proper Resource Management
Always ensure that resources (files, memory, etc.) are properly released, even when exceptions occur. Use try-finally
blocks to guarantee cleanup code is executed.
Not Using Proper Data Structures
Use appropriate data structures for your needs. In modern Pascal, use dynamic arrays, lists, dictionaries, and other collection classes instead of fixed-size arrays.
Not Using Units for Code Organization
Organize your code into units (modules) with clear responsibilities. This improves maintainability, reusability, and compilation times.
Not Using Strong Type Definitions
Use strong type definitions and structured data types to make your code more type-safe and self-documenting.
Not Using Function Results
Use function return values instead of var
parameters for outputs. This makes the code more readable and allows for function composition.
Not Using Proper String Handling
Use modern string types and operations instead of fixed-length character arrays and manual string manipulation. This makes your code more readable and less error-prone.
Not Using Proper Documentation
Document your code with comments that explain the purpose, parameters, return values, and any important details or assumptions. This makes your code more maintainable and easier for others to understand.
Not Using Proper Object-Oriented Design
In modern Object Pascal, use object-oriented design principles like encapsulation, inheritance, and polymorphism to create more maintainable and extensible code.