Bluefin is an effect system for Haskell which allows you, through value-level handles, to freely mix a variety of effects including

• Bluefin.EarlyReturn, for early return
• Bluefin.Exception, for exceptions
• Bluefin.IO, for I/O
• Bluefin.State, for mutable state
• Bluefin.Stream, for streams

For an introduction to Bluefin, see the docs in the Bluefin module.

There is an bluefin-examples package which you can see in this repository at bluefin-examples/src/Bluefin/Examples.

Tom Ellis would like to thank many individuals for their work related to effect systems. Without the work of these individuals, Bluefin would not exist.

• Oleg Kiselyov, particularly for his work on effects and delimited continuations

• Michael Snoyman, particularly for his work on conduit and the ReaderT IO pattern

• Gabriella Gonzalez, particularly for her work on pipes

• Alexis King, particularly for her work on effect systems and delimited continuations

• David Feuer, particularly for his observation about handlers and rank-2 types

• Andrzej Rybczak for his work on effectful

• Francois Pottier for "Wandering through linear types, capabilities, and regions"

• Jasper van de Jeugt, particularly for promoting the handle pattern

• Michael Thompson, for his work on streaming

• Ningning Xie and Daan Leijen, for their work on Koka

• Andrej Bauer and Matija Pretnar, for their work on Eff