Functional programming is a paradigm which attempts to solve computational problems by the chained evaluation of functions whose output is determined by their inputs rather than the programme state. In this style of programming, side effects and mutable data are deprecated and usually strictly ...

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parallel computing list of objects

I have a list of objects that all require the exact same filtering, basically a set of conditionals in a function which outputs if the object is "good" or "bad". I want to keep all of my "good" ...
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In functional programming, are local mutable variables with no side effects still considered “bad practice”?

Is having mutable local variables in a function that are only used internally, (e.g. the function has no side effects, at least not intentionally) still considered "non functional"? e.g. in the ...
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177 views

Functional Programming: efficiently handling whole world changes? [duplicate]

Imagine we're creating a multiplayer dungeon crawl (a roguelike) using FP where we emphasize pure functions and immutable data structures. We generate a dungeon composed of rooms, corridors, heroes, ...
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Functional Programming: right ideas about concurrency and state?

FP proponents have claimed that concurrency is easy because their paradigm avoids mutable state. I don't get it. Imagine we're creating a multiplayer dungeon crawl (a roguelike) using FP where we ...
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Is there any difference between pointers and references? [duplicate]

References and pointers do the same thing as I know. Is there any difference between them? If there is no difference, why we call them reference not pointer?
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Is Haskell/Clojure actually unsuited for dynamic systems such as particle simulation?

I've been told in previous questions that functional programming languages are unsuited for dynamic systems such as a physics engine, mainly because it's costly to mutate objects. How realistic is ...
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190 views

What is “Semantics visibility”?

I'm reading 97 Things Every Programmer Should Know, now I'm positioned in "Apply Functional Programming Principles", and there is a paragraph that says: ...A leading cause of defects in imperative ...
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428 views

Functional Reactive/Relational Programming – Is there a difference?

I've been using Reactive Cocoa (by GitHub), a Functional Reactive Programming API for use with the Cocoa libraries for a while now, but have just read "Out of the Tar Pit", the paper that supposedly ...
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583 views

Ring of numbers where adjacent entries sum up to a prime

Given a number n, find a permutation of the numbers 1...n such that all adjacent entries sum up to primes. If such a permutation does not exist, throw an error. Is there a purely-functional way to do ...
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109 views

Permuting a list of numbers by pushing and popping onto a stack

Suppose we have some long stack of numbers. There is another intermediate stack, and a destination stack to be returned in the end. The only two operations allowed is transferring the top of the old ...
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594 views

Performance of single-assignment ADT oriented code on modern CPUs

Working in immutable data with single assignments has the obvious effect of requiring more memory, one would presume, because you're constantly creating new values (though compilers under the covers ...
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615 views

Are “normal order” and “call-by-name” the same thing?

I was studying the book Structure and Interpretation of Computer Programs and in section 1.1.5 The Substitution Model for Procedure Application the author explains the concepts of normal order and ...
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implement cons function in Java - type safety question

I am working on a small functional library written in Java, which mimics the a functional style of programming. I am stuck with a undesirable type cast in one of my method definitions and would love ...
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143 views

LOOP program only need inc and zero

I have 4 different commands in LOOP programming language: y=Zero() y=Val(x)=copy x and put it in register y y=Inc(x)=x+1 y=Dec(x)=x-1 Finally I also have loop n times { ... ...
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1answer
150 views

LOOP-computable functions

I was just reading a chapter about LOOP-computable functions and I have the following question: Is it possible to numerate every LOOP program with an algorithm? Formally: Is it possible to have a ...
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What is the functional-programming alternative to an interface?

If I want to program in a "functional" style, with what would I replace an interface? interface IFace { string Name { get; set; } int Id { get; } } class Foo : IFace { ... } Maybe a ...
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Is Rebol a functional programming language?

I ran into Rebol and I was wondering about it. I ran into the following script from here: use [feed questions answers][ feed: load-xml/dom http://stackoverflow.com/feeds/tag/rebol ...
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10answers
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How to write useful Java programs without using mutable variables

I was reading an article about functional programming where the writer states (take 25 (squares-of (integers))) Notice that it has no variables. Indeed, it has nothing more than three ...
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210 views

Practical reference for learning about graph reduction

Are there any practical references (with actual examples) for getting started implementing a small, lazy functional programming language with graph reduction? A reference that included the lexing and ...
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720 views

Functional reactive programming — is Fay expressive enough?

So I'm doing a fairly involved javascript/html client with lots of ajax calls and other involvements of callback-ism. I'm entertaining the thought of using Fay for this purpose. I'm aware of Elm. ...
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273 views

Who first coined the term Higher Order Function and/or First Class Citizen?

I've come to understand that long before Haskell, O'Caml or LISP, higher order functions were an academic research subject and in mathematics, Schönfinkel (in 1967) and Haskell Curry (in 1968) already ...
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419 views

What's a good math textbook to have on my desk while studying Haskell? [closed]

I just started learning Haskell and it seems like you can't get too far in the language without being comfortable ( or at least exposed ) to certain branches of mathematics. Unfortunately I have major ...
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What is the advantage of currying?

I just learned about currying, and while I think I understand the concept, I'm not seeing any big advantage in using it. As a trivial example I use a function that adds two values (written in ML). ...
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What's the difference in content between Chris Okasaki's 1996 thesis and 1999 book, Purely Functional Data Structures?

I want to read Purely Functional Data Structures. I've easily found the thesis (which is freely available as a PDF), but see that there's a book available also. So I'd like to know what the ...
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What is the current state of SECD and SKI machine use and research? [closed]

I'm doing some independent research/study with a professor who's a very functional guy. The goal is to examine more of what's happening behind the scenes with functional languages than we normally ...
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Better to use error monad with validation in your monadic functions, or implement your own monad with validation directly in your bind?

I'm wondering what's better design wise for usability/maintainability, and what's better as far as fitting with the community. Given the data model: type Name = String data Amount = Out | Some | ...
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Why (or why not) are existential types considered bad practice in functional programming?

What are some techniques I might use to consistently refactor code removing the reliance on existential types? Typically these are used to disqualify undesired constructions of your type as well as to ...
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How to code in a more functional style in Java?

I code Java for at least 5 years now and I really appreciate how the language works. When looking at new JVM languages (e.g. Scala, Clojure) there is a trend to more functional ways to code and this ...
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364 views

Devising test of Haskell's value/reference semantics

In imperative languages, it is trivial to devise a programming test of language's use of "value semantics" or "reference semantics". One could do the following and check the value of a (where Vertex ...
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Java memory management (thunks/lazyness)

If I want to create an infinite list of integers in Java like so: ArrayList<Integer> list = new ArrayList<Integer>(); for(int i = 0;;i++){ list.add(i); } I run out of memory. My ...
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Sorting : Useful for more than just viewing data?

Context I'm currently working on a personal project involving functional reactive JavaScript, and I've come up with an odd question. Note that this question is not JavaScript specific, but that is ...
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1answer
543 views

Is Clojure a 3GL or a 4GL?

A bit of background (in case I'm mistaken)... I think I understand that (it's an oversimplification): manually entering codes into memory (or on a punchcard) is "first generation language" using ...
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Reasons for removal of function types in Java 8

I have been trying to understand why the JDK 8 Lambda Expert Group (EG) decided not to include a new function type into the Java programming language. Going over the mailing list I found a thread ...
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Determinism of functions using PRNG in Clojure and functional languages

I'm a bit surprised by a sentence found in the book "Clojure Programming" (1st [and only as I write this!?] edition), page 78: It should be obvious that it's impossible to deterministically test a ...
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In functional programming, does having most of the data structures immutable require more memory usage?

In functional programming since almost all data structure are immutable, when the state has to change a new structure is created. Does this mean a lot more memory usage? I know the object oriented ...
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C++ Design: Functional Programming vs OOP

Design Question Recently, I've been doing more and more FP in C++, mostly in the form of function templates and lambdas, and heavy overloading of a single function name. I really like FP for some ...
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1answer
137 views

Network computation

I'm pretty sure that someone has already thought about it and researched it extensively, but I'm having trouble finding any materials or even keywords to look for, for the idea that I was thinking ...
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2answers
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Misconceptions about purely functional languages?

I often encounter the following statements / arguments: Pure functional programming languages do not allow side effects (and are therefore of little use in practice because any useful program does ...
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6answers
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Functional programming compared to OOP with classes

I have been interested in some of the concepts of functional programming lately. I have used OOP for some time now. I can see how I would build a fairly complex app in OOP. Each object would know how ...
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4answers
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Performance: recursion vs. iteration in Javascript

I have read recently some articles (e.g. http://dailyjs.com/2012/09/14/functional-programming/) about the functional aspects of Javascript and the relationship between Scheme and Javascript (the ...
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Fastest Functional Language

I've recently been delving into functional programming especially Haskell and F#, the prior more so. After some googling around I could not find a benchmark comparison of the more prominent functional ...
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299 views

What does “polyadic” mean in the context of functional programming and type systems?

And how does it (or does not) correspond to "polymorphic"? Occasionally I see this notion like in: Implement and represent polyadic operations. I checked Wiktionary but it only gives a general ...
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3answers
913 views

Why can't we write nested shorthand functions in Clojure?

I tried to evaluate a Clojure expression with nested shorthand functions today, and it wouldn't let me. The expression was: (#(+ % (#(+ % (* % %)) %)) 5) ; sorry for the eye bleed The output was: ...
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4answers
788 views

What's special about currying or partial application?

I've been reading articles on Functional programming everyday and been trying to apply some practices as much as possible. But I don't understand what is unique in currying or partial application. ...
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1answer
142 views

Does automatic returning affect performance?

There's a bunch of languages that automatically return the last value in a function (mostly functional) like Ruby, Haskell, Lisp, etc. Does this feature (or what do you call it) affect the ...
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3answers
316 views

Is there a name for this functional programming construct/pattern?

I wrote a function and I'd like to find out if it is an implementation of some functional programming pattern or construct. I'd like to find out the name of this pattern or construct (if it exists)? ...
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5answers
530 views

Compute if a function is pure

As per Wikipedia: In computer programming, a function may be described as pure if both these statements about the function hold: The function always evaluates the same result value given the ...
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2answers
331 views

What's the benefit of the Nothing constructor in Haskell?

I'm new to Haskell and I'm not really sold on the Nothing constructor. It sounds like just another silent fail that's going to create headaches down the line. It seems much more useful to throw an ...
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Using foldr to append two lists together (Haskell)

I have been given the following question as part of a college assignment. Due to the module being very short, we are using only a subset of Haskell, without any of the syntactic sugar or idiomatic ...
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Functional Methods on Collections

I'm learning Scala and am a little bewildered by all the methods (higher-order functions) available on the collections. Which ones produce more results than the original collection, which ones ...