We introduce a new lambda calculus with futures, Lambda(fut), that models the operational semantics of concurrent statically typed functional programming languages with mixed eager and lazy threads such as Alice ML, a concurrent extension of Standard ML. Lambda(fut) is a minimalist extension of the call-by-value lambda-calculus that is sufficiently expressive to define and combine a variety of standard concurrency abstractions, such as channels, semaphores, and ports. Despite its minimality, the basic machinery of Lambda(fut) is sufficiently powerful to support explicit recursion and call-by-need evaluation. We present a static type system for Lambda(fut) and distinguish a fragment of Lambda(fut) that we prove to be uniformly confluent. This result confirms our intuition that reference cells are the sole source of indeterminism.
Dependent type theory is rich enough to express that a program satisfies an input/output relational specification, but it could be hard to construct the proof term. On the other hand, squiggolists know very well how to show that one relation is included in another by algebraic reasoning. We demonstrate how to encode functional and relational derivations in a dependently typed programming language. A program is coupled with an algebraic derivation from a specification, whose correctness is guaranteed by the type system. Code accompanying the paper has been developed into an Agda library AoPA.
The cb2Bib is a free, open source, and multiplatform application for rapidly extracting unformatted, or unstandardized bibliographic references from email alerts, journal Web pages, and PDF files. The cb2Bib facilitates the capture of single references from unformatted and non standard sources. Output references are written in BibTeX. Article files can be easily linked and renamed by dragging them onto the cb2Bib window. Additionally, it permits editing and browsing BibTeX files, citing references, searching references and the full contents of the referenced documents, inserting bibliographic metadata to documents, and writing short notes that interrelate several references.
This is CamlPDF, an OCaml library for reading, writing and manipulating Adobe portable document files. CamlPDF consists of a set of low level modules for representing, reading and writing the basic structure of PDF, together with an initial attempt at a higher level API.
We create concept maps, a type of model, to explore and learn about complex information spaces. By showing everything—the forest and the trees—in a single view, concept maps help people create mental models and clarify thoughts. We create concept maps to share understanding— with our clients, peers, and others interested in the subjects. Please note: many of our concept maps are poster size. They can be printed at smaller sizes (11 x 17), but may be difficult to read. A few of the maps have been printed and are available through our office.
Daniel Fridlender Mia Indrika March 2001 Inspired by Danvy, we describe a technique for defining, within the Hindley-Milner type system, some functions which seem to require a language with dependent types. We illustrate this by giving a general definition of zipWith for which the Haskell library provides a family of functions, each member of the family having a different type and arity. Our technique consists in introducing ad hoc codings for natural numbers which resemble numerals in lambda-calculus
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