The "Dynamics" describe how a program steps from one state to the next. Using , you write rules that dictate exactly how an expression evaluates. This is where you learn about:
You start thinking like a type checker. You begin to catch "impossible" bugs before you even hit compile because you've designed your data structures to be mathematically sound.
Writing code that works across multiple types (generics). 3. Dynamics: Execution Models 15312 foundations of programming languages
The climax of the course is proving . Together, these two properties guarantee that if a program passes the type checker, it will either finish with a result or keep making progress—it will never crash or enter an undefined state. Why Study It?
The course focuses on the study of programming language phenomena using the tools of and Operational Semantics . Instead of looking at languages like Java or Python as monolithic tools, you learn to see them as a collection of "features" (functions, recursion, exceptions, parallelism) that can be formally defined and proven correct. The Pillars of the Course 1. Abstract Syntax The "Dynamics" describe how a program steps from
When exactly does an argument get computed?
To master the material covered in 15-312, the primary text is almost always by Robert Harper. It is a dense, rigorous, but incredibly rewarding guide to the field. You begin to catch "impossible" bugs before you
The journey begins by moving away from "concrete syntax" (the curly braces and semicolons) and toward . You learn that a program is a structured mathematical object, not just a string of characters. 2. Statics: Type Systems
The famous slogan "Well-typed programs do not go wrong."