Yampa

Yampa is a domain-specific embedded language for the programming of hybrid (discrete and continuous time) systems using the concepts of Functional Reactive Programming (FRP). Yampa is structured using Arrows, which greatly reduce the chance of introducing space- and time-leaks into reactive, time-varying systems.

Yampa was originally developed by the Yale Haskell Group based on the original idea of Conal Elliott's Fran.

Download Animas (most up to date Yampa fork, or download original Yampa)

Introduction

• Henrik Nilsson - A Brief Introduction to Functional Reactive Programming and Yampa
• Henrik Nilsson - ITU-FRP2010
  • ITU-FRP2010 01
  • ITU-FRP2010 02
  • ITU-FRP2010 03
  • ITU-FRP2010 04
  • ITU-FRP2010 05
  • ITU-FRP2010 06
  • ITU-FRP2010 07
• Paul Hudak - Yampa, Arrows, and Robots
• Yampa tutorials by Gerold Meisinger
  • Running primitive signal functions in Yampa
  • Yampa/SDL program stub
  • Learning Yampa and Functional Reactive Programming
  • Diagrams of Yampa switches
  • Dataflow diagram of Yampa reactimate
  • Activity diagram of Yampa reactimate
• shaleny LazyFoo SDL examples translated to Haskell/Yampa (lecture 16-)
• References: ps, pdf
• Videos
  • Safe Functional Reactive Programming through Dependent Types
  • Causal Commutative Arrows and Their Optimization
  • Euterpea: From signals to symphonies

Primitive signal functions

(download original Image:Yampa signal functions.svg‎)

Switches

• switch
• rSwitch
• kSwitch
• pSwitchB
• pSwitch
• rpSwitchB
• rpSwitch

Each switch comes in two different flavors:

1. immediate: switch to the new behaviour immediately and also calculate the return value based on the new behaviour.
2. delayed: return the value based on the old behaviour, but use the new behaviour afterwards. To use delayed switch prefix the switching functions with the letter 'd', f.e. 'drpSwitchB'.

Reactimation

• reactimate
• Game engine

External Links

• Yampa-Users mailing list - Yampa-related comments, questions, discussions, and announcements. You can also send bug reports to yampa-bugs@cs.yale.edu.
• George Giorgidze created YampaSynth, a modular music synthesizer written in Haskell and using Yampa.
• [1] - Hai (Paul) Liu papers and slides
• Blog about Yampa - introduction tutorials and diagrams
• Demonstrating a Time Leak in Arrowized FRP
  • answer

Known users

• YampaSynth - is a software synthesizer implemented in Haskell using Yampa. It contains a framework of sound generating and sound shaping modules (e.g. oscillator, amplifier, mixer, envelope generator, filter, etc.) and example applications.
• Frag; a simple Quake 3 clone, using a very early version of Yampa called arrowized functional reactive programming (AFRP)
• Space Invaders; a video game, demonstrating the usage of Yampa
• Nettle - Programming Network Routers
• Euterpea - computer music development (also uses CCA)

Known forks

• Animas
  • code cleanup
  • Facts and Theories blog by Edward Amsden
• FRVR
  • restructuring of modules
  • DIVE project
  • Kristopher J. Blom - Dynamic, Interactive Virtual Environments section 8.3