Typing rule

Typing rules are formal specifications that define how types are assigned to expressions in programming languages. These rules help determine whether an expression is well-typed, meaning that it adheres to the language's rules about type compatibility, and they ensure that operations on data types are performed safely and correctly. Typing rules are essential for: 1. **Type Safety**: Ensuring that programs do not produce type errors during execution. A well-typed program should only perform operations on compatible types.