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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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 ...
23
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6answers
3k views

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 ...
13
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4answers
6k views

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 ...
9
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3answers
6k views

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 ...
1
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1answer
403 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 ...
8
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3answers
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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: ...
8
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4answers
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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. ...
2
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1answer
143 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 ...
3
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3answers
342 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)? ...
10
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5answers
707 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 ...
3
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2answers
347 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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4answers
4k views

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 ...
6
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3answers
549 views

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 ...
2
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2answers
575 views

design a model for a system of dependent variables

I'm dealing with a modeling system (financial) that has dozens of variables. Some of the variables are independent, and function as inputs to the system; most of them are calculated from other ...
25
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5answers
3k views

Does immutability entirely eliminate the need for locks in multi-processor programming?

Part 1 Clearly Immutability minimizes the need for locks in multi-processor programming, but does it eliminate that need, or are there instances where immutability alone is not enough? It seems to ...
5
votes
2answers
345 views

Can higher-order functions in FP be interpreted as some kind of dependency injection?

According to this article, in object-oriented programming / design dependency injection involves a dependent consumer, a declaration of a component's dependencies, defined as interface contracts, an ...
2
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1answer
1k views

What is the difference between functional relational programming and functional programming?

After reading both this thread and the linked paper, I don't understand how FRP (functional relational programming) is different from (FP) functional programming. Does FRP augment or replace FP? Can ...
7
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1answer
3k views

C++11 support for higher-order list functions

Most functional programming languages (e.g. Common Lisp, Scheme / Racket, Clojure, Haskell, Scala, Ocaml, SML) support some common higher-order functions on lists, such as map, filter, takeWhile, ...
2
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1answer
160 views

Guidelines for creating referentially transparent callables

In some cases, I want to use referentially transparent callables while coding in Python. My goals are to help with handling concurrency, memoization, unit testing, and verification of code ...
9
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5answers
800 views

What's the proper term for a function inverse to a constructor - to unwrap a value from a data type?

Edit: I'm rephrasing the question a bit. Apparently I caused some confusion because I didn't realize that the term destructor is used in OOP for something quite different - it's a function invoked ...
3
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3answers
556 views

Internal Mutation of Persistent Data Structures

To clarify, when I mean use the terms persistent and immutable on a data structure, I mean that: The state of the data structure remains unchanged for its lifetime. It always holds the same data, ...
11
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8answers
2k views

Why isn't functional language syntax more close to human language?

I'm interested in functional programming and decided to get head to head with Haskell. My head hurts... but I'll eventually get it... I have one curiosity though, why is the syntax so cryptic (in lack ...
5
votes
5answers
908 views

When to use functional programming approach and when not? (in Java)

let's assume I have a task to create a Set of class names. To remove duplication of .getName() method calls for each class, I used org.apache.commons.collections.CollectionUtils and ...
7
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1answer
2k views

Why does Scala require functions to have explicit return type?

I recently began learning to program in Scala, and it's been fun so far. I really like the ability to declare functions within another function which just seems to intuitive thing to do. One pet ...
12
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2answers
544 views

Are there any specific workflows or design patterns that are commonly used to create large functional programming applications?

I have been exploring Clojure for a while now, although I haven't used it on any nontrivial projects. Basically, I have just been getting comfortable with the syntax and some of the idioms. Coming ...
11
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2answers
432 views

FP for simulation and modelling

I'm about to start a simulation/modelling project. I already know that OOP is used for this kind of projects. However, studying Haskell made me consider using the FP paradigm for modelling a system of ...
4
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3answers
801 views

From Imperative to Functional Programming

As an Electronic Engineer, my programming experience started with Assembly and continue with PL/M, C, C++, Delphi, Java, C# among others (imperative programming is in my blood). I'm interested in ...
5
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2answers
493 views

How to have a maintainable and manageable Javascript code base [closed]

I am starting a new job soon as a frontend developer. The App I would be working on is 100% Javascript on the client side. all the server returns is an index page that loads all the Javascript files ...
15
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2answers
2k views

Equivalent of SOLID principles for functional programming

I've found the SOLID principles quite useful when thinking about object-oriented design. Is there a similar / equivalent set of language-agnostic principles tailored for functional programming?
18
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8answers
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Why is the concept of lazy evaluation useful?

It seems lazy evaluation of expressions can cause a programmer to lose control over the order in which their code is executed. I am having trouble understanding why this would be acceptable or desired ...
23
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6answers
3k views

Is functional programming a superset of object oriented?

The more functional programming I do, the more I feel like it adds an extra layer of abstraction that seems like how an onion's layer is- all encompassing of the previous layers. I don't know if this ...
8
votes
5answers
2k views

Functional programming readability

I'm curious about this because I recall before learning any functional languages, I thought them all horribly, awfully, terribly unreadable. Now that I know Haskell and f#, I find it takes a little ...
19
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3answers
1k views

Why is the rec keyword needed in F#?

In F# it is necessary to use the rec keyword. In Haskell there is no need to explicitly tell if a given function is recursive or not. Given the role of recursion in functional programming, the F# ...
6
votes
2answers
1k views

Differences between imperative-language and functional-language debuggers

Up to now I have always worked with imperative languages like Pascal, C, C++, Java in a production environment, so I have experience with debuggers for these languages (Turbo Pascal, Turbo C, GDB / ...
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5answers
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Critique of the IO monad being viewed as a state monad operating on the world

The IO monad in Haskell is often explained as a state monad where the state is the world. So a value of type IO a monad is viewed as something like worldState -> (a, worldState). Some time ago I ...
23
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3answers
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Different ways to see a monad

While learning Haskell I have faced a lot of tutorials trying to explain what are monads and why monads are important in Haskell. Each of them used analogies so it would be easier to catch the ...
14
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1answer
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Does Clojure have the continuation?

I started programming with Python. When using python, concepts like coroutine, closure made me really confusing. Now I think I know them some superficial level, but I want to get the "enlightement" ...
6
votes
3answers
5k views

Is it a better practice pre-initialize attributes in a class, or to add them along the way?

I'm sorry if this is a ABSOLUTELY sophomoric question, but I'm curious what the best practices are out there, and I can't seem to find a good answer on Google. In Python, I usually use an empty class ...
5
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4answers
865 views

How are objects modelled in a functional programming language?

In an answer to this question (written by Pete) there are some considerations about OOP versus FP. In particular, it is suggested that FP languages are not very suitable for modelling (persistent) ...
7
votes
3answers
613 views

What statements and approaches should I avoid when learning functional programming?

I have 6 years of programming experience, mostly following the object oriented paradigm, and I'm interested in learning functional programming. My main goal is to become a functional paradigm ...
4
votes
3answers
236 views

Is an Inner Function Justified in this Situation

I'm new to the functional programming concepts in C#, but I have some experience with higher order functions via Haskell, Scala, Python and Ruby. I'm currently going through an old .NET 2.0 codebase ...
38
votes
7answers
4k views

Are small amounts of functional programming understandable by non-FP people?

Case: I'm working at a company, writing an application in Python that is handling a lot of data in arrays. I'm the only developer of this program at the moment, but it will probably be ...
0
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2answers
667 views

I cannot understand the application of oops How can I develop the understanding of application of oops? [on hold]

I am a developer in PHP technology, I am aware of almost all the basics of OOPS, but still cannot find out the way to apply these concepts over a procedural programming. I do it in very orthodox way, ...
2
votes
2answers
1k views

Performance of concurrent software on multicore processors [closed]

Recently I have often read that, since the trend is to build processors with multiple cores, it will be increasingly important to have programming languages that support concurrent and parallel ...
2
votes
2answers
741 views

Functional Programming, JavaScript and UI - some neophyte questions

In the discussion here, the comments in the accepted answer suggest that I approach the given code from a functional perspective, which was new to me at the time. Wikipedia said, among other things, ...
17
votes
2answers
886 views

What are the typical applications of Lisp macros?

I am trying to learn some LISP and I have read a lot about the importance of LISP macros so I would like to get some working experience with them. Can you suggest a practical application area that ...
7
votes
3answers
717 views

A deque based on binary trees

This is a simple immutable deque based on binary trees. What do you think about it? Does this kind of data structure, or possibly an improvement thereof, seem useful? How could I improve it, ...
6
votes
3answers
687 views

Am I getting Scheme wrong?

Inspired by the numerous posts about the importance of learning Lisp/Scheme I started to learn Scheme two days back, I am using the book "The little Schemer" and have completed half of it. But I ...
3
votes
2answers
2k views

Equivalent of Domain Driven Design for functional programming languages

I really love the idea of domain driven design, however, as I'm learning Go, I'm wondering if there's the equivalent of DDD that's aimed at an effectively more functional language?
2
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2answers
490 views

How do functional languages handle a mocking situation when using Interface based design?

Typically in C# I use dependency injection to help with mocking; public void UserService { public UserService(IUserQuery userQuery, IUserCommunicator userCommunicator, IUserValidator userValidator) ...