Title
Generalized iteration and coiteration for higher-order nested datatypes
Abstract
We solve the problem of extending Bird and Paterson's generalized folds for nested datatypes and its dual to inductive and coinductive constructors of arbitrarily high ranks by appropriately generalizing Mendler-style (co)iteration. Characteristically to Mendler-style schemes of disciplined (co)recursion, the schemes we propose do not rest on notions like positivity or monotonicity of a constructor and facilitate programming in a natural and elegant style close to programming with the customary letrec construct, where the typings of the schemes, however, guarantee termination. For rank 2, a smoothened version of Bird and Paterson's generalized folds and its dual are achieved; for rank 1, the schemes instantiate to Mendler's original (re)formulation of iteration and coiteration. Several examples demonstrate the power of the approach. Strong normalization of our proposed extension of system Fω of higher-order parametric polymorphism is proven by a reduction-preserving embedding into pure Fω.
Year
DOI
Venue
2003
10.1007/3-540-36576-1_4
FoSSaCS
Keywords
Field
DocType
generalized fold,guarantee termination,elegant style close,pure f,higher-order nested datatypes,generalized iteration,customary letrec,coinductive constructor,system f,high rank,higher-order parametric polymorphism,mendler-style scheme,higher order,parametric polymorphism
Discrete mathematics,Monotonic function,Inductive type,Normalization (statistics),Embedding,Computer science,Generalization,Parametric polymorphism,Coinduction,Recursion
Conference
Volume
ISSN
ISBN
2620
0302-9743
3-540-00897-7
Citations 
PageRank 
References 
6
0.48
18
Authors
3
Name
Order
Citations
PageRank
Andreas Abel11319.57
Ralph Matthes220121.67
Tarmo Uustalu358055.11