Give a language, the Interpreter design pattern defines a representation for its grammar along with an interpreter that uses the representation to interpret sentences in the language.
The Interpreter Design Pattern provides a way to evaluate language grammar or expression. This pattern is used in SQL Parsing, Symbol Processing Enginee, etc.
UML Class Diagram
Context: This is a class that contains information that is going to be used by the interpreter ot interpret.
AbstractExpression: This is an interface that defines the interpret method which should be impletmented by the subclasses. This method takes the context object as a parameter. This context object holds the data we want to interpret.
TerminalExpression: This is a concrete class that implements the AbstractExpression interface. The TerminalExpression represents elements in the grammar that do not get replaced such as symbols.
NonTerminalExpression: This is also a concrete class that implements the AbstractExpression interface. The NonTerminalExpression represents elements in the grammar that do not get replaced such as symbols.
Client: This is a class that builds the abstract syntax tree for a set of instructions in the given grammar.This tree builds with the help of instances of NonTerminalExpression and TerminalExpression classes.
When to use the Interpreter Design Pattern in C#?
- Grammar is simple
- Efficiency is not a critical concern