Writing a Type-Inferring Compiler: From Conditionals to Functions

Understanding how programming languages automatically determine types without explicit annotations can feel like magic. This text-based course demystifies type inference by guiding you through the mechanics of building a compiler that understands types on its own. You will transition from writing simple parsers to designing an intelligent compiler that analyzes control flow and function definitions. By studying the core algorithms of type deduction, you will gain a deep appreciation for language design and type safety, enabling you to build more robust software tools. What you'll learn: Understand the fundamentals of type systems, AST representations, and type deduction rules; Implement type inference for conditional statements to resolve branch types automatically; Design type-checking algorithms for function declarations and recursive function calls; Apply modern error-handling patterns to report clear and actionable type mismatch errors; Practice translating abstract typing rules into clean, structured compiler code. The course begins with foundational concepts of type theory and AST construction before moving step-by-step through inferring conditionals, handling variable declarations, and resolving complex function signatures. This course is designed for programmers new to compiler development who want to understand type systems from the ground up, with no prior compiler-writing experience required. Start reading today to unlock the inner workings of modern type-inferring compilers.