Questions tagged [functional-programming]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
590
votes
6answers
120k views

What's new in purely functional data structures since Okasaki?

Since Chris Okasaki's 1998 book "Purely functional data structures", I haven't seen too many new exciting purely functional data structures appear; I can name just a few: IntMap (also invented by ...
29
votes
1answer
1k views

Programming languages with canonical functions

Are there any (functional?) programming languages where all functions have a canonical form? That is, any two functions that return the same values for all set of input is represented in the same way, ...
52
votes
2answers
6k views

What are the outstanding questions in purely functional data structures?

This question is inspired by another question about what's new in PFDS since the publication of Okasaki's book in 1998. I'll start with two questions I have: Is there a purely functional set data ...
46
votes
2answers
6k views

Explaining Applicative functor in categorical terms - monoidal functors

I'd like to understand Applicative in terms of category theory. The documentation for Applicative says that it's a strong lax ...
17
votes
2answers
2k views

What persistent data structure for a set of partially ordered elements?

I need to store sets of elements of type a. Type a is partially ordered, so comparing $a_1$ and $a_2$ can return smaller, greater, equal or incomparable. One problem with hashtables is that two equal ...
9
votes
8answers
6k views

What are the simplest turing-complete systems? [closed]

Lambda Calculus is very simple. Are there even simpler turing-complete systems? Which is the simplest of them all?
15
votes
1answer
1k views

A mathematical (categorical) description of type classes

A functional language can be viewed as a category where its objects are types and morphisms functions between them. How do type classes fit in this model? I assume we should only consider those ...
14
votes
0answers
361 views

Are there simple core languages which are consistent and expressive?

The Calculus of Constructions is a very simple core functional language with dependent types. Per curry-howard isomorphism, it could, potentially, be very useful for writing programs and proofs. It, ...
14
votes
3answers
598 views

Associative hash mixing

Consider the lowly singly-linked list in a purely functional setting. Its praises have been sung from the mountain tops and will continue to be sung. Here I will address one among its many strengths ...
10
votes
1answer
793 views

Algorithm to determine function equality on the simply typed lambda calculus?

We know that beta-equality of simply typed lambda-terms is decidable. Given M,N:σ→τ, is it decidable whether for all X:σ, MX $≃_β$ NX?
4
votes
0answers
496 views

Is it possible to derive induction by extending CoC with recursion?

Suppose we extended the CoC with primitive recursion; that is, we added a term µ x . t such that equality allowed unrolling recursive terms: ...
7
votes
1answer
196 views

Is it possible to unambiguously read back λ terms from interaction nets without node types?

A class of lambda terms can be evaluated using Lamping's abstract algorithm - that is, converting them to interaction nets and applying a set of rules. In order to get the result, you have to read ...
3
votes
1answer
323 views

Learning road map for functional programming from the viewpoint of category theory

I am now considering about studying functional programming from the viewpoint of category theory. There are a lot of books about functional programming and category theory, I want some suggestions ...
3
votes
0answers
204 views

Is it possible to check equality of equi-recursive types, or recursive λ-terms?

Can we determine if two λ-terms are equal? Given two lambda terms, let's say they are equal if their (possibly infinite) Bohm trees are. Under this definition, for example, ...
1
vote
0answers
44 views

Is it possible to use arbitrary fixpoint values on EAL without losing strong normalization?

From this question, the answerer states EAL-based languages can use arbitrary fixpoint types without losing strong normalization, because their normalization (and complexity) properties comes from ...