I started with the data structures and felt okay there, primitives and tuples weren't bad.
Start by defining the type system's core components: a type representation (primitives, generics, tuples, functions) and a unification algorithm for inference. Then outline the inference process using a constraint-based approach, and discuss how to handle mismatches and conflicts with clear error messages. Finally, consider trade-offs like performance, extensibility, and implementation complexity.
Pro tip: Emphasize the importance of a robust unification algorithm and demonstrate how you'd handle edge cases like recursive types or infinite unification. Also, mention that you'd design the type system to be extensible for future features like type classes or subtyping.
Design data structures to represent primitive types, generic type variables, tuples (nested), and function signatures. Consider using an AST-like structure with type constructors.
Choose a constraint-based inference approach: generate constraints from the program, then solve them using unification. Explain how to handle generics by treating them as type variables to be resolved.
Detail the unification algorithm: recursively compare types, bind type variables, and detect mismatches. Discuss handling of nested tuples and function types, and how to avoid infinite loops with occurs check.
Describe how to report type mismatches and conflicts (e.g., unifying int with string, or conflicting generic bindings). Emphasize clear error messages with source locations.
Talk about performance (e.g., union-find for efficient unification), extensibility (e.g., adding subtyping or type classes), and limitations of the toy system.
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