au:chlipala Ur introduces richer type system features into FP. Ur is functional, pure, statically-typed, and strict. Ur supports metaprogramming based on row types. Ur/Web is standard library and associated rules for parsing and optimization. Ur/Web supports construction of dynamic web applications backed by SQL databases. The signature of the standard library is such that well-typed Ur/Web programs "don't go wrong" in a very broad sense. They also may not: * Suffer from any kinds of code-injection attacks * Return invalid HTML * Contain dead intra-application links * Have mismatches between HTML forms and the fields expected by their handlers It is also possible to use metaprogramming to build significant application pieces by analysis of type structure - demo includes an ML-style functor for building an admin interface for an arbitrary SQL table. The Ur/Web compiler also produces very efficient object code that does not use gc
A Tutorial Implementation of a Dependently Typed Lambda Calculus Andres Löh, Conor McBride and Wouter Swierstra We present the type rules for a dependently-typed core calculus together with a straightforward implementation in Haskell. We explicitly highlight the changes necessary to shift from a simply-typed lambda calculus to the dependently-typed lambda calculus. We also describe how to extend our core language with data types and write several small example programs. The paper is accompanied by an executable interpreter and example code that allows immediate experimentation with the system we describe. Download Draft Paper (submitted to FI) Haskell source code (executable Haskell file containing all the code from the paper plus the interpreter; automatically generated from the paper sources) prelude.lp (prelude for the LambdaPi interpreter, containing several example programs) Instructions (how to get started with the LambdaPi interpreter)
In denotational semantics and functional programming, the terms monad morphism, monad layering, monad constructor, and monad transformer have by now accumulated 20 years of twisted history. The exchange between Eric Kidd and sigfpe about the probability monad prompted me to investigate this history