87 research outputs found
Boxy Types: Inference for Higher-Rank Types and Impredicativity
Languages with rich type systems are beginning to employ a blend of type inference and type checking, so that the type inference engine is guided by programmer-supplied type annotations. In this paper we show, for the first time, how to combine the virtues of two well-established ideas: unification-based inference, and bidirectional propagation of type annotations. The result is a type system that conservatively extends Hindley-Milner, and yet supports both higher-rank types and impredicativity
Simple, partial type-inference for System F based on type-containment
We explore partial type-inference for System F based on type-containment. We consider both cases of a purely functional semantics and a call-by-value stateful semantics. To enable type-inference, we require higher-rank polymorphism to be user-specified via type annotations on source terms. We allow implicit predicative type-containment and explicit impredicative type-instantiation. We obtain a core language that is both as expressive as System F and conservative over ML. Its type system has a simple logical specification and a partial type-reconstruction algorithm that are both very close to the ones for ML. We then propose a surface language where some annotations may be omitted and rebuilt by some algorithmically defined but logically incomplete elaboration mechanism
Constraint Handling Rules with Binders, Patterns and Generic Quantification
Constraint Handling Rules provide descriptions for constraint solvers.
However, they fall short when those constraints specify some binding structure,
like higher-rank types in a constraint-based type inference algorithm. In this
paper, the term syntax of constraints is replaced by -tree syntax, in
which binding is explicit; and a new generic quantifier is introduced,
which is used to create new fresh constants.Comment: Paper presented at the 33nd International Conference on Logic
Programming (ICLP 2017), Melbourne, Australia, August 28 to September 1, 2017
16 pages, LaTeX, no PDF figure
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