In object-oriented languages, the Visitor pattern can be used to traverse tree-like data structures: a visitor object contains some operations, and the data structure objects allow themselves to be traversed by accepting visitors. In the polymorphic lambda calculus (System F), tree-like data structures can be encoded as polymorphic higher-order functions. In this paper, we reconstruct the Visit...

We describe isolation and characterization of the first microsatellite loci specifically developed for African weakly electric fish (Mormyridae), for the genus Campylomormyrus . Seventeen of our 18 loci are polymorphic within the Campylomormyrus numenius species complex . The polymorphic loci showed four to 15 alleles per locus, an expected heterozygosity between 0.46 and 0.94, and an observed ...

In the polymorphic -calculus, one may explicitly define functions that take a type as input and return a term as output. This work focuses on how such functions depend on their input types. Indeed, these functions are generally understood to have an essentially constant meaning on input types. We show how the proof theory of the polymorphic -calculus suggests a clear syntactic description of th...

By polymorphic Π1 types we mean types of the polymorphic lambda calculus (system F) in which Π only occurs positively. For such types the question of inhabitation is decidable and observational equivalence corresponds to βη-equivalence and is representable by a term. Furthermore, in the PER-model based on untyped λ-terms universality holds for all Π1 types (all elements can be typed). At the en...

We formalise and study the notion of polymorphic algebraic theory, as understood in the mathematical vernacular as a theory presented by equations between polymorphically-typed terms with both type and term variable binding. The prototypical example of a polymorphic algebraic theory is System F, but our framework applies more widely. The extra generality stems from a mathematical analysis that ...

The capability calculus is a framework for statically reasoning about program resources such as deallocatable memory regions. Fractional capabilities, originally proposed by Boyland for checking the determinism of parallel reads in multi-thread programs, extend the capability calculus by extending the capabilities to range over the rational numbers. Fractional capabilities have since found nume...

Continuing the study of reconfigurable architectures, two other architectures with finer grain reconfiguration are covered: PipeRench [1] and MIT RAW processor [2]. MIT RAW processor consists of sixteen single issue cores connected via a low latency communication network over the chip. PipeRench is a reconfigurable array of processing elements and programmable interconnection networks between t...

Existing type literature has conflicting views on desugaring polymorphic lets to lambda terms. The conflict arises because, in certain cases, desugaring does not preserve typing. We describe a transformation of polymorphic lets to monomorphic lets such that, when the monomorphic lets are desugared, the typing is preserved. Our transformation requires no changes to either term or type syntax. Th...

This paper describes a tool suite for the ACL2 programming language which incorporates certain ideas from the Hindley-Milner paradigm of functional programming (as exemplified in popular languages like ML and Haskell), including a “typed” style of programming with the ability to define polymorphic types. These ideas are introduced via macros into the language of ACL2, taking advantage of ACL2’s...

In the domain of spatial computing, it appears that platforms based on either reconfigurable datapath units or on hybrid microprocessor/logic cell organizations are in the ascendancy as they appear to offer the most efficient means of providing resources across the greatest range of hardware designs. This paper encompasses an initial exploration of an alternative organization. It looks at the e...