bound: Combinators for manipulating locally-nameless generalized de Bruijn terms

[ bsd3, compilers-interpreters, language, library ] [ Propose Tags ]

The goal of this package is to make it as easy as possible to deal with name binding without forcing an awkward monadic style on the user. To that end we provide haskell 98 combinators for manipulating locally-nameless generalized de Bruijn terms, build over user-supplied term types. A generalized de Bruijn term is one where you can succ whole trees instead of just individual variables.

The approach was first elaborated in Bird and Patterson, "de Bruijn notation as a nested data type":

However, the combinators they used required higher rank types. Here we use a monad transformer to encapsulate the novel recursion pattern in their generalized de Bruijn representation. It is named Scope to match up with the terminology from Conor McBride and James McKinna's "I am not a number: I am a free variable", while providing stronger type safety guarantees.

There are three worked examples in the examples folder:

Versions [faq] 0.1, 0.1.1, 0.1.2, 0.1.3, 0.1.4, 0.2, 0.2.1, 0.3.1, 0.3.2, 0.4, 0.5,,, 0.5.1, 0.6, 0.6.1, 0.7, 0.8, 0.8.1, 0.9,, 0.9.1,, 1.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.0.6, 1.0.7, 2, 2.0.1
Dependencies base (==4.*), bifunctors (>=0.1.3 && <0.2), prelude-extras (==0.2.*), transformers (>=0.2 && <0.4) [details]
License BSD-3-Clause
Copyright Copyright (C) 2012 Edward A. Kmett
Author Edward A. Kmett
Maintainer Edward A. Kmett <>
Category Language, Compilers/Interpreters
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Source repo head: git clone git://
Uploaded by EdwardKmett at Sat Jun 16 08:18:05 UTC 2012
Distributions LTSHaskell:2.0.1, NixOS:2.0.1, Stackage:2.0.1
Downloads 15888 total (492 in the last 30 days)
Rating 2.5 (votes: 4) [estimated by rule of succession]
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