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Why I Prefer Functional Programming

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Re: Why I Prefer Functional Programming

#51

Post by jlg23 »

uxp100 wrote: post #28
biznickman wrote: post #2

I think this most effectively demonstrates why I like a lot of OOP: it can be verbose. This is example function is relatively illegible: alignCenter :: [String] -> [String] alignCenter xs = map (\x -> replicate (div (n - length x) 2) ' ' ++ x) xs where n = maximum (map length xs) One of the most verbose languages I've used, Objective C, has made this a best practice. Despite the brackets (which scare people off), it…

I don't really like 'where n' afterwards instead of say 'let n' at the beginning, but I'm not very familiar with haskell (really just enough to know the first line is a type signature) and I found this ok. Maybe objective C is better though.

My first thought, too. OTOH, with indentation like in the example I could live with it.

Re: Why I Prefer Functional Programming

#52

Post by klodolph »

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

This may be more common with Haskell specifically, because Haskell makes currying so easy and has tools like http://pointfree.io/ (which I’ve definitely abused before).

Re: Why I Prefer Functional Programming

#53

Post by jimbokun »

hinkley wrote: post #31
biznickman wrote: post #2

I think this most effectively demonstrates why I like a lot of OOP: it can be verbose. This is example function is relatively illegible: alignCenter :: [String] -> [String] alignCenter xs = map (\x -> replicate (div (n - length x) 2) ' ' ++ x) xs where n = maximum (map length xs) One of the most verbose languages I've used, Objective C, has made this a best practice. Despite the brackets (which scare people off), it…

I'm finding that in Javascript, I really enjoy map() and filter(), but map() caused some friction on code reviews at one place, from someone I don't think had any FP background. The are best when they are one liners, of the form .map((val) => someFunction(val)) or .filter((val) => val.length > 1) reduce() on the other hand is always illegible to me. I get pretty grumpy when I am 'forced' to use a reduce because the c…

"but map() caused some friction on code reviews at one place"

Someone not familiar or comfortable with "map" should not be working as a professional programmer today. Most languages now support "map" or something very similar.

Try to move to a different team or different company with actual professional developers.

Re: Why I Prefer Functional Programming

#54

Post by p4bl0 »

ummonk wrote: post #34
biznickman wrote: post #2

I think this most effectively demonstrates why I like a lot of OOP: it can be verbose. This is example function is relatively illegible: alignCenter :: [String] -> [String] alignCenter xs = map (\x -> replicate (div (n - length x) 2) ' ' ++ x) xs where n = maximum (map length xs) One of the most verbose languages I've used, Objective C, has made this a best practice. Despite the brackets (which scare people off), it…

A list comprehension in python would be more comprehensible than either AND less verbose.

Arguably, list comprehension in Python is already functional programming :).

Re: Why I Prefer Functional Programming

#55

Post by WorldMaker »

BalinKing wrote: post #8
biznickman wrote: post #2

I think this most effectively demonstrates why I like a lot of OOP: it can be verbose. This is example function is relatively illegible: alignCenter :: [String] -> [String] alignCenter xs = map (\x -> replicate (div (n - length x) 2) ' ' ++ x) xs where n = maximum (map length xs) One of the most verbose languages I've used, Objective C, has made this a best practice. Despite the brackets (which scare people off), it…

I honestly think a good amount of legibility is a matter of familiarity. I've used Haskell for a couple of years, and I didn't find this code particularly illegible (if I had to guess, this is probably more easily-understandable to me than the equivalent OOP formulation). That's not to dismiss your criticism, not at all; rather, I think that the challenge would decrease with experience.

To underscore the point that legibility is as much a matter of familiarity as anything else: I think a big difference with an "OOP language" like the above poster seems to prefer versus Haskell has a lot more to do with the English language keyword operators that most contemporary OOP languages favor versus Haskell favoring more mathematical notation.

There exist "OOP Languages" like OG Smalltalk, Self, Io that might make for better comparisons to Haskell by virtue of being closer to the simpler syntax and general focus on more "mathematical" operators. Just as there exist more functional languages that use much more of an English keyword approach than Haskell.

(Some forms of Lisp/Scheme are so English keyword-forward with micro-DSLs that they may be a better example in a lot of posts like these for comparing "contempory OOP languages" and "functional languages". Plus there's all the bits of hybridized "functional languages" embedded directly inside contemporary "OOP" languages such as LINQ syntax in C#. It's interesting to me how many of these sorts of articles jump straight to Haskell.)

Re: Why I Prefer Functional Programming

#56

Post by nnq »

uxp100 wrote: post #28
biznickman wrote: post #2

I think this most effectively demonstrates why I like a lot of OOP: it can be verbose. This is example function is relatively illegible: alignCenter :: [String] -> [String] alignCenter xs = map (\x -> replicate (div (n - length x) 2) ' ' ++ x) xs where n = maximum (map length xs) One of the most verbose languages I've used, Objective C, has made this a best practice. Despite the brackets (which scare people off), it…

I don't really like 'where n' afterwards instead of say 'let n' at the beginning, but I'm not very familiar with haskell (really just enough to know the first line is a type signature) and I found this ok. Maybe objective C is better though.

You can write code without ever using `where ...` :)

It's just how mathematicians are used to express their version of "top down problem solving". It's also similar to what you do when you define a function/method before the smaller ones it calls and before the even smaller ones they call (using what's called "function hoisting" in Javascript for example).

Now, if you really dislike "top down problem solving", you might have an allergic reaction to `where ...` which applies the same pattern but does it down even to the micro level of small functions of few lines...

Re: Why I Prefer Functional Programming

#57

Post by yoz-y »

jimbokun wrote: post #43
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…

"To me this looks like perl golfing" I think that's preposterous and totally unfounded. The identifiers have names like "alignCenter", "replicate", "maximum" and "length". Those are all actual full English words, nothing remotely obfuscated about them. "map", "++" for concatenation, and "x/xs" for an arbitrary list of things are all idiomatic so can be kept short because they are used so often, like pronouns in Engli…

Ok.

My problem with functional programming written like this (I admit that this example is too short) is that once there are too many functions combining with other functions it is very easy to lose thread of what is happening. My comparison with perl is more to the point that these programs are way easier to write than read.

Again, this example is too simplistic to illustrate my point, but what I like with combining imperative and functional programming is that it is easier to keep trace of what is happening by using intermediate variables that hold the state and thus break the chain of functions.

Re: Why I Prefer Functional Programming

#58

Post by tel »

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 can totally be abused. It's also, in my opinion, often very useful for clarity.

It's my experience that, especially with FP code, often the important things to write down are the stages/steps in a transformation and that the intermediate outputs do not, by themselves, hold much semantic meaning.

Pointfree lets you write just those steps. Moving to "point-full" coding forces you to give names to these semantically meaningless intermediates. This can sometimes just be noise.

Terseness is also just shocking sometimes. It can take time to get used to it. I feel like when I read more verbose languages I skim each block of code numerous times and collect the meaning iteratively. When I read Haskell, I depend upon each name having distinct and important semantic meaning, I leverage type information heavily, and when I do read something I read each word carefully.

Totally different styles, but I've found strong preference for terseness.

Re: Why I Prefer Functional Programming

#59

Post by marcosdumay »

nnq wrote: post #47
biznickman wrote: post #2

I think this most effectively demonstrates why I like a lot of OOP: it can be verbose. This is example function is relatively illegible: alignCenter :: [String] -> [String] alignCenter xs = map (\x -> replicate (div (n - length x) 2) ' ' ++ x) xs where n = maximum (map length xs) One of the most verbose languages I've used, Objective C, has made this a best practice. Despite the brackets (which scare people off), it…

What is illegible about that?! It just says, in code: "replace each line of text with itself prefixed by a number of spaces equal with half of the difference between its length and the length of the longest line in the text". It's like the most obvious way to think about this particular problem! Now, how well this scales to different problems, and especially to problems where mutation is a natural way to think about…

As usual in FP code, the order of your words are completely different from the order things appear in the code. Also, most developers aren't used to concise function declarations (yeah, even with JS pushing them), what further adds to the problem.

This is not something people with no experience on FP can read easily. Now, calling it illegible strongly implies that people with no FP experience are the metric one should code for, what is perfectly valid if you are at a company aiming to hire cheap coders, but not something to brag about.

Re: Why I Prefer Functional Programming

#60

Post by thsealienbstrds »

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

Maybe true, but writing readable code is a difficult thing in any language. No matter what language you're using, you're going to have to come up with a set of coding standards in the long run.
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