Category Archives: Types

Type safety, Validation and verification

Ad-Hoc External State Models

Posted on 2013 March 23 by

Encapsulation, Accessibility, Security One of the main reasons we encapsulate state is to gain more control over how it updates. For example, take your traditional, imperative, mutable state variables that respond to get and put actions. We might use one … Continue reading →

Posted in Concurrency, Language Design, Modularity, Open Systems Programming, Reactive Demand Programming, State, Types | 1 Comment

Stone Soup Programming

Posted on 2012 September 12 by

Stone soup programming is meant to evoke an image of throwing software components into a pot – in no particular order, and paying little attention to the ingredients – and the result being a nice application. The glue code between … Continue reading →

Posted in Language Design, Live Programming, Modularity, Reactive Demand Programming, Stability, Types | 6 Comments

Exponential Decay of History

Posted on 2012 August 20 by

There are many problems for which it is useful to keep a history. A few examples of such problems: keep history of control-flow in an application for debugging purposes keep history of updates to a document for undo purposes keep … Continue reading →

Posted in Language Design, Stability, State, Types, User Interface | 3 Comments

Make for Haskell values, part alpha

Posted on 2012 April 12 by

…Make is a monad transformer… I commanded Google to search the web on my behalf for word of Dependency Injection in Haskell. I was disappointed to see only a few ruminations on using typeclasses. Inflexible, static, global typeclasses. Impenetrability! That’s … Continue reading →

Posted in Language Design, Modularity, Open Systems Programming, Types | Leave a comment

Freedom and Crutches in Language Design

Posted on 2011 October 13 by

Language designers aim to optimize an experience for their prospective users, but the criteria and heuristics by which they ‘optimize’ are widely varied and inconsistent (often within a single designer). In this article, I’ll present two common points of contention … Continue reading →

Posted in Language Design, Types | 19 Comments

Trouble with Typestate

Posted on 2011 September 26 by

If you are unfamiliar with it, typestate is a property explored by several new general purpose programming languages such as Plaid and Rust. The idea is to lift object states into the type system – i.e. initialization status, or whether … Continue reading →

Posted in Language Design, Types | Leave a comment

Linear Types and RDP?

Posted on 2011 August 31 by

I’ve been thinking recently about how I might achieve linearity types for RDP. A type is ‘linear’ if it must be consumed at least once… and at most once. Linear types are very useful. They can be used to enforce … Continue reading →

Posted in Language Design, Reactive Demand Programming, State, Types | 2 Comments

Signals in RDP

Posted on 2011 July 19 by

Reactive Demand Programming (RDP) describes behavior as signal transformers, in continuous time, with side-effects. For example, I might push a control signal to a camera (to influence pan, zoom, tilt, and focus), and the camera will provide a response signal … Continue reading →

Posted in Concurrency, Distributed Programming, Language Design, Reactive Demand Programming, Types | 2 Comments

Protect Your Semantics

Posted on 2011 June 22 by

A FIFO is a valid strategy to implement actors model, in the sense that it doesn’t violate any actors model semantics. But there are serious problems with using this strategy: developers will test their programs with it and never see … Continue reading →

Posted in Language Design, Types | Leave a comment