314 research outputs found
Proof of the principal type property for system O
We study a minimal extension of the Hindley/Milner system that
supports overloading and polymorphic records.
We also show that every typable term in this system has a
principal type and give an algorithm to reconstruct that type.
We give the proofs for termination, soundness and correctness for
the constrained unification and the type reconstruction algorithm
Fighting bit Rot with Types (Experience Report: Scala Collections)
We report on our experiences in redesigning Scala\u27s collection
libraries, focussing on the role that type systems play in keeping
software architectures coherent over time. Type systems can make
software architecture more explicit but, if they are too weak, can
also cause code duplication. We show that code duplication can be
avoided using two of Scala\u27s type constructions: higher-kinded types
and implicit parameters and conversions
Type inference with constrained types
In this paper we present a general framework HM(X) for
Hindley/Milner style type systems with constraints, analogous
to the CLP(X) framework in constrained logic programming.
We present sufficient conditions on the constraint domain X
so that the principal types property carries over to HM(X).
The conditions turn out to be fairly simple and natural.
The usage of the aproach is demonstrated in instantion
of parameter X with several known type disciplines.
We consider extensible records, typeclasses, overloading
and subtyping
A second look at overloading
We study a minimal extension of the Hindley/Milner system that
supports overloading and polymorphic records. We show that the type
system is sound with respect to a standard untyped compositional
semantics. We also show that every typable term in this system has a
principal type and give an algorithm to reconstruct that type
A second look at overloading
We study a minimal extension of the Hindley/Milner system that
supports overloading and polymorphic records. We show that the type
system is sound with respect to a standard untyped compositional
semantics. We also show that every typable term in this system has a
principal type and give an algorithm to reconstruct that type
A confluent calculus for concurrent constraint programming with guarded choice
. Confluence is an important and desirable property as it allows the program to be understood by considering any desired scheduling rule, rather than having to consider all possible schedulings. Unfortunately, the usual operational semantics for concurrent constraint programs is not confluent as different process schedulings give rise to different sets of possible outcomes. We show that it is possible to give a natural confluent calculus for concurrent constraint programs, if the syntactic domain is extended by a blind choice operator and a special constant standing for a discarded branch. This has application to program analysis. 1 Introduction Concurrent constraint programming (ccp) [16, 15] is a recent programmingparadigm which elegantly combines logical concepts and concurrency mechanisms. The computational model of ccp is based on the notion of a constraint system, which consists of a set of constraints and an entailment relation. Processes interact through a common store. Commun..
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