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Why I Prefer Functional Programming

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Re: Why I Prefer Functional Programming

#141

Post by Traubenfuchs »

Dear functional programmer, please do not slam on languages you do not even know how to program in. To be honest, I have no idea what this code is even supposed to do and which idea of "centering" it satisfies. Whether this mess of Java or the mess of Haskell the blog writer created is more readable is up to you. C# has been functional forever and Java caught up a lot.

  int maxLength = Stream.of(text).map(String::length).max(Integer::compareTo).get();
  IntStream.range(0, text.length).forEach(i -> text[i] = " ".repeat((maxLength - text[i].length()) / 2) + text[i]);
(This becomes significantly more readable if you change the contract from passing an array of Strings to passing a list and returning a list. Since functional programmers are so in love with immutability: Java now provides immutable lists in the standard lib.)

Re: Why I Prefer Functional Programming

#142

Post by imtringued »

AlexCoventry wrote: post #18

I prefer functional programming because referentially transparent functions are easier to reason about and test. Brevity of control flow hasn't brought me much benefit.

Unfortunately nowadays the majority of my functions are not referentially transparent.

Re: Why I Prefer Functional Programming

#143

Post by almostdeadguy »

AllegedAlec wrote: post #137

> Obviously, composition over inheritance strives a bit against one of the original key concepts of OOP - which is inheritance. I don't understand why people keep pushing this idea of OOP as requiring classes and inheritance, when it very much does not. Also, it's really easy to say that FP is better than OOP, or the other way around, when people keep comparing their favourite with a straw-manned version of the other…

I assume you're referring to the definition of OOP coming from the Alan Kay quote: “OOP to me means only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things."

This definition includes nearly every language with modules, polymorphism, and depending what counts as message passing might either dis-include statically typed languages, languages without a defined model of concurrency that disallows shared mutable state, or languages without message passing library support.

If that's what canonically counts as OOP, there's no straw-manning going on here, the discussion is just a comparison against a pretty well-defined category of programming languages with different features that are often described as and understood to be object-oriented.

Whenever people bring this up I often hear that Erlang is supposed to be the canonical object-oriented language, and if that's the case, I'm not sure how we could call this discussion straw-manning, because it's just talking about totally different languages.

Re: Why I Prefer Functional Programming

#145

Post by n4r9 »

apta wrote: post #112
isodude wrote: post #87

Earlier quoted context omitted.

A simple thing like a DNS resolve is much simpler in non FP. FP shines when it's more complex, but not when it's simple. I find Go-lang a reasonable crossover where you could do a lot of FP in it where it is needed and keep it simple and boring in the rest. It's like me as an engineer: Don't use me for simple tasks because I will make them really complex.

> I find Go-lang a reasonable crossover where you could do a lot of FP in it When people talk about FP, they usually include things like pattern matching and generics, none of which golang has. Not to mention it actively prohibits chaining functions that return errors because of the botched way it decided to handle errors as a product type instead of the correct way as sum type. golang is a very imperative language w…

tbh if you have the ability to easily treat functions as first class citizens in a language then it's fair enough to say you can code functionally in it.

I think the attitude "X is inherently a functional language" is being replaced by the idea that there are clusters of language properties with labels like "functional" or "object-oriented" or "array-based" or whatever, and that a language may overlap with bits of various clusters to a greater or lesser degree.

Re: Why I Prefer Functional Programming

#146

Post by n4r9 »

0xcoffee wrote: post #92
yoz-y wrote: post #17

Earlier quoted context omitted.

To me this looks like perl golfing, but for some reason perl golfing is bad but writing extremely terse functional programs is not. Personally I like to combine both approaches. In swift I would write something like this: let l = ["abc", "ab", "abcdef", "abcdefgh"] width = l.reduce(0, { max($0, $1.count) }) let centered = l.map({ (line: String) -> String in var padding = (width - line.count) / 2 return String(repeati…

Obligatory C#: var input = new string[] { "abc", "ab", "abcdef", "abcdefgh" }; var maxLength = input.Select(e => e.Length).Max(); var output = input.Select(e => { var padding = (maxLength - e.Length) / 2; return new String(' ', padding) + e; }); Most modern `oop` languages these days all support functional constructs and achieve the same thing in same amount of code & style. Language and oop/functional style are not…

I tend to avoid doing a Select followed straight by a Max when you can just pass the select function directly into the max. Also multiline lambda expressions feel ugly but that's probably just me! This is what I would do these days:

    string pad(this string e, int padLength) => new String(' ', padLength) + e;
    var input = new string[] { "abc", "ab", "abcdef", "abcdefgh" };
    var maxLength = input.Max(e => e.Length);
    var output = input.Select(e => e.pad((maxLength - e.Length) / 2));

Re: Why I Prefer Functional Programming

#147

Post by itsbruce »

roywiggins wrote: post #40
andolanra wrote: post #30

Earlier quoted context omitted.

I think this is a question that's orthogonal to OOP-versus-functional-programming, but is rather about programming style. Haskell programmers like being terse, but there's also nothing stopping you from writing Haskell like this: alignCenter :: [String] -> [String] alignCenter lines = let maxLineLength = maximum (map length lines) in [ leftPadding ++ line | line You could have verbose and easy-to-read functional code…

Functional programming seems to let people lapse into "point-free style" fairly easily, which (imho) has a much greater chance of becoming rapidly unreadable. Not to say FP can't be readable as you've demonstrated very well. https://en.wikipedia.org/wiki/Tacit_programming

Point free style possible in languages like Haskell and SML where the syntax makes it practical. Haskell and SML make it easy, Scala does not. If you made an OOP language with the right syntax features, you could have point-free style in that language too. You can do point-free style in Python with just a little effort. It's orthogonal to the FP/OOP debate.

Re: Why I Prefer Functional Programming

#148

Post by newen »

misja wrote: post #122
newen wrote: post #113

Earlier quoted context omitted.

Honestly...how is that more readable? It's more verbose sure but the first example is much more readable and straightforward. Here, you have to remember Haskell's list comprehension syntax and you have to scan up and down a few times to keep track of the variables.

The main benefit of example 2 IMO is that some variables got readable names. E.g. n became maxLineLength and x became line. But bad naming practices have nothing to do with FP per se. Although it does seem to be fashionable in part of the FP community to have everything as terse as possible including variable names.

To me, code with terse variables are much more readable since it's much easier to keep track of the variables when scanning the code. When I read that piece of code above, I didn't try to ascertain meaning from the variable names which, it's arguable whether I (or anyone) should or not since coders can assign variables arbitrary names.

Re: Why I Prefer Functional Programming

#149

Post by apta »

isodude wrote: post #114
apta wrote: post #112

Earlier quoted context omitted.

> I find Go-lang a reasonable crossover where you could do a lot of FP in it When people talk about FP, they usually include things like pattern matching and generics, none of which golang has. Not to mention it actively prohibits chaining functions that return errors because of the botched way it decided to handle errors as a product type instead of the correct way as sum type. golang is a very imperative language w…

Agreed, it's still relatively possible to invent stuff that is missing though. It will grow :)

Not without having a proper way to handle errors, and generics at the very least.

Re: Why I Prefer Functional Programming

#150

Post by tombert »

iainmerrick wrote: post #131
tombert wrote: post #110

Earlier quoted context omitted.

Sorry, you'd need to use the MyType* x to use the `new` keyword; it's been awhile. It doesn't really deter from my point though; in order to heap-allocate something you have to use a pointer, and you end up doing something not that dissimilar from Java . > C++ is nothing at all like Java. Is that supposed to be a joke? Java was marketed specifically towards C++ engineers...

Javascript was marketed towards Java programmers, and those languages are pretty different from each other too.

I would say that C++ is closer to Java than JavaScript is; it's fairly easy to copy-paste and edit C++ code into a Java file with, just changing a small amount of syntax and get rid of the manual memory allocations.

Try copy-pasting JS into a Java file, and there are semantics there that are completely foreign; you can't simply translate it.

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