Unamb

Abstract

unamb is a package containing the unambiguous choice operator unamb, which wraps thread racing up in a purely functional, semantically simple wrapper. Given any two arguments u and v that agree unless bottom, the value of unamb u v is the more terminating of u and v. Operationally, the value of unamb u v becomes available when the earlier of u and v does. The agreement precondition ensures unamb's referential transparency. For more info about unamb and its use, see the paper Simply Efficient Functional Reactivity, sections 10 and 11.

unamb was originally a part of Reactive. I moved it to its own package in order to encourage experimentation.

Besides this wiki page, here are more ways to find out about unamb:

• Visit the Hackage page for library documentation and to download & install.
• Or install with cabal install unamb.
• Get the code repository: darcs get http://code.haskell.org/unamb.

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