Principal type inference for GHC-Style multi-parameter type classes

Authors:
Martin Sulzmann;Tom Schrijvers;Peter J. Stuckey
Affiliations:
School of Computing, National University of Singapore, Singapore;Department of Computer Science, Katholieke Universiteit Leuven, Heverlee, Belgium;NICTA Victoria Laboratory, Department of Computer Science and Software Engineering, The University of Melbourne, Australia
Venue:
APLAS'06 Proceedings of the 4th Asian conference on Programming Languages and Systems
Year:
2006

Citing 14
Cited 3

Unification revisited

Foundations of deductive databases and logic programming
Unification under a mixed prefix

Journal of Symbolic Computation
Type inference with polymorphic recursion

ACM Transactions on Programming Languages and Systems (TOPLAS)
Polymorphic type inference and abstract data types

ACM Transactions on Programming Languages and Systems (TOPLAS)
Type classes in Haskell

ACM Transactions on Programming Languages and Systems (TOPLAS)
Putting type annotations to work

POPL '96 Proceedings of the 23rd ACM SIGPLAN-SIGACT symposium on Principles of programming languages
Principal type-schemes for functional programs

POPL '82 Proceedings of the 9th ACM SIGPLAN-SIGACT symposium on Principles of programming languages
Type Classes with Functional Dependencies

ESOP '00 Proceedings of the 9th European Symposium on Programming Languages and Systems
An Overview of HAL

CP '99 Proceedings of the 5th International Conference on Principles and Practice of Constraint Programming
Structural Subtyping of Non-Recursive Types is Decidable

LICS '03 Proceedings of the 18th Annual IEEE Symposium on Logic in Computer Science
Haskell and principal types

Haskell '03 Proceedings of the 2003 ACM SIGPLAN workshop on Haskell
A theory of overloading

ACM Transactions on Programming Languages and Systems (TOPLAS)
Understanding functional dependencies via constraint handling rules

Journal of Functional Programming
A framework for extended algebraic data types

FLOPS'06 Proceedings of the 8th international conference on Functional and Logic Programming

Complete and decidable type inference for GADTs

Proceedings of the 14th ACM SIGPLAN international conference on Functional programming
Analysing graph transformation systems through constraint handling rules

Theory and Practice of Logic Programming
Outsidein(x) modular type inference with local assumptions

Journal of Functional Programming - Dedicated to ICFP 2009

Quantified Score

Hi-index	0.00

Visualization

Abstract

We observe that the combination of multi-parameter type classes with existential types and type annotations leads to a loss of principal types and undecidability of type inference. This may be a surprising fact for users of these popular features. We conduct a concise investigation of the problem and are able to give a type inference procedure which, if successful, computes principal types under the conditions imposed by the Glasgow Haskell Compiler (GHC). Our results provide new insights on how to perform type inference for advanced type extensions.