Recursive calls over recursive data are useful for generating probability distributions, and
probabilistic programming allows computations over these distributions to be expressed in a …

The expression problem describes how most types can easily be extended with new ways to
produce the type or new ways to consume the type, but not both. When abstract syntax trees …

We characterize the relation between generalized algebraic datatypes (GADTs) with pattern
matching on their constructors one hand, and generalized algebraic co-datatypes …

Static types are a great form of lightweight static analysis. But sometimes a type like List is
too coarse–we would also like to work with its refinements like non-empty lists, or lists …

The expression problem describes a fundamental trade-off in program design: Should a
program's primary decomposition be determined by the way its domain objects are …

Data types and codata types are, as the names suggest, often seen as duals of each other.
However, most programming languages do not support both of them in their full generality …

Functional programming language design has been shaped by the framework of natural
deduction, in which language constructs are divided into introduction and elimination rules …

Programming languages are embracing both functional and object-oriented paradigms. A
key difference between the two paradigms is the way of achieving data abstraction. That is …

Traditionally, formal languages are defined as sets of words. More recently, the alternative
coalgebraic or coinductive representation as infinite tries, ie, prefix trees branching over the …

The lambda calculus and algebraic data types are the two pillars on which the theory of
statically typed functional programming languages is built. The lambda calculus was …