Ml-style Typing, Lambda Lifting, and Partial Evaluation

Lambda lifting transforms local function deenitions in functional programming languages into global ones to facilitate their eecient implementation. When considered as a source-to-source transformation for an ML-style typed language, all published algorithms for lambda lifting break typability. We break down two representative lambda lifting algorithms into four elementary transformation steps, analyze their typing properties, and deene alternative steps that preserve ML typability where appropriate. Putting the revised steps together, we deene a lambda lifter that preserves ML-style typability. Our algorithm provides a starting point for implementing eecient generating extensions that perform ooine partial evaluation for polymorphically typed languages.