Nalen

How OCaml Represents Values in Memory

Nalen

This presentation details OCaml's critical distinction between immediate and boxed types, explaining how tagged integers and heap-allocated blocks with specific headers enable efficient memory layout and garbage collection. It outlines the precise bit-level encoding strategies for primitives, variants, and special types like floats and strings, while noting the runtime's ability to dynamically inspect values and its constraints on non-immediate constructor counts. The discussion concludes by affirming the current system's performance benefits and previewing future optimization efforts toward integrating unboxed types.