Functional programming in C++

Abstract

This paper describes FC++: a rich library supporting functional programming in C++. Prior approaches to encoding higher order functions in C++ have suffered with respect to polymorphic functions from either lack of expressiveness or high complexity. In contrast, FC++ offers full and concise support for higher-order polymorphic functions through a novel use of C++ type inference.Another new element in FC++ is that it implements a subtype polymorphism policy for functions, in addition to the more common parametric polymorphism facilities. Subtype polymorphism is common in object oriented languages and ensures that functions in FC++ fit well within the C++ object model.Apart from these conceptual differences, FC++ is also an improvement in technical terms over previous efforts in the literature. Our function objects are reference-counted and can be aliased without needing to be copied, resulting in an efficient implementation. The reference-counting mechanism is also exported to the user as a general-purpose replacement of native C++ pointers. Finally, we supply a number of useful functional operators (a large part of the Haskell Standard Prelude) to facilitate programming with FC++. The end result is a library that is usable and efficient, while requiring no extensions to the base C++ language.

Implementing Persistent O(1) Stacks and Queues in R

“…Further work might consider implementing additional persistent data structures, such as red-black trees or heaps. Because persistent versions of these are often O(log n) amortized insertion and removal, it may be beneficial to implement them via Rcpp and functional approaches for C++ (McNamara and Smaragdakis, 2000;Eddelbuettel and François, 2011;Eddelbuettel, 2013).…”

Simple algebraic data types for C

“…Second, it is possible to use ADTs and pattern matching in a standard language, usually C + +. For example McNamara and Smaragdakis 16 focus on the polymorphic typing issues and Läufer 17 focuses on the higher order issues. The Boost libraries for C + + 18 have also been used to build a library for ADTs.…”

Implementing exact real arithmetic in python, C++ and C

“…To achieve this in a way that is convenient for the programmer to use is possible, but not simple. Of several attempts at this I have selected the FC++ library by McNamara and Smaragdakis [14]. I will briefly describe the features of this library which make it particularly appropriate for implementing exact real arithmetic.…”