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SOLID Design Principles in Smalltalk coding

The SOLID in SOLID Design Principles is an acronym or mnemonic for five basic patterns of object oriented design.
The object-oriented nature of coding in Smalltalk makes it straightforward to apply each principle, providing a basic framework for designing new classes. This is especially useful when working on group projects and a standardized system for creation of classes and interaction between classes is needed and isn't immediately obvious.

The following definitions are obtained from wikipedia http://en.wikipedia.org/wiki/Solid_(object-oriented_design)

SRP : Single Responsibility Principle

OCP : Open/Closed Principle

LSP : Liskov Substitution Principle

ISP : Interface Segregation Principle

DIP : Dependency Inversion Principle

A problem that can occur in team projects is classes picking up method parameters & variables that are were defined after creation in subclasses. Doing this causes problems in all dependent classes & most probably a repeating cycle of debugging.
To avoid this it is important to make sure that high-level modules should not depend on low-level modules, but instead on abstractions. These abstractions do not depend on details, instead the details or complications should extend on the absrtactions.

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