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> One of the big reasons why FP languages have so little penetration is because the advocacy usually feels like someone trying to talk you into a religion. Eh,

> One of the big reasons why FP languages have so little penetration is because the advocacy usually feels like someone trying to talk you into a religion. Eh, I doubt it. I've encountered a few Haskell snobs in my time, but most people that I know who use FP do so completely silently and will discuss the merits and (and challenges) with you freely. I think the real issues with FP are lack of good tooling, package management, and being a major shift in thinking for most developers. It's a common theme for someone to say that learning FP (seriously) was the most impactful thing they've done to improve their software chops. > The other major impediment is gatekeeping ??? what? I guess you could argue that pure vs non-pure functions are gatekeeping, but there are absolutely legitimate benefits to pure functions that basically everyone can agree on.

AnimalMuppet 4y ago
"A monad is just a monoid in the category of endofunctors". Anyone who says that - or anything anywhere close to it - is gatekeeping, no matter how true the statement is. And it's not just the statement. It seems to me (from my outside perspective) that category theory is often used in a gatekeeping way. In contrast, take SQL. How much of the mathematical theory of relations do you need to know to be able to write SQL queries? Yes, it might help, but the SQL gurus don't try to drag you into it every time you get close to a database.
- lliamander 4y ago
  > "A monad is just a monoid in the category of endofunctors". Anyone who says that - or anything anywhere close to it - is gatekeeping, no matter how true the statement is. Quite frankly, if you don't understand that sentence then you are in no position to judge whether the concepts could be made more accessible. Sometimes the important question is not "could this be easier to learn?" but "is learning it worth the effort?".
- Iceland_jack 4y ago
  Notions of Computation as Monoids https://www.fceia.unr.edu.ar/~mauro/pubs/Notions_of_Computation_as_Monoids.pdf https://www.fceia.unr.edu.ar/~mauro/pubs/Notions_of_Computat...
- packetlost 4y ago
  SQL is intrinsically tied to set theory and borrows a ton of terminology and logic from set theory. Whether you understand that it's from mathematics or not doesn't really matter. You are using set theory and it's terminology regardless. I've only really ever seen monoids referred to in Haskell. If you actually read my comment, Haskell is not all FP (no PL is). It's not even a significant portion of FP. So just don't use Haskell, it's hardly the first FP language I would reach for and it's probably not the one you should either. Also, any person willing to learn would be intrigued by the terminology, not reject it as something that's "gatekeeping". Such a defeatist attitude will not get you very far in a field as complex as this.
  - tsimionescu 4y ago
    SQL was explicitly designed to appeal to business people, and uses strictly familiar words and phrases. It was very explicitly designed (though I would say it has mostly failed) to read like pseudo-natural language. SQL DBs and the precise semantics of SQL are somewhat based on relational algebra, but SQL syntax is definitely not. It's also not using set theoretic terms in general, with the exception of UNION and INTERSECT.
  - TexanFeller 4y ago
    SQL tables are not actually sets at all since you can insert duplicate rows! In practice they usually are though.
    - packetlost 4y ago
      You can't actually insert a complete duplicate row because the ROWID (or whatever your particular RDBMS calls it) is a implicit, but unique property of each row (and corresponds to the offset in the file the row is located at). Further, while tables can be the identity element of all records they contain, they themselves aren't really a set. Usually when people associate set theory with SQL, it's with queries (and their results).
- marcosdumay 4y ago
  Nobody says that seriously. It tells a lot how people go for common jokes to complain about a community. It's easy to fall for that if you never actually interacted with the people.
- the_af 4y ago
  Nobody claims you have to understand category theory to write Haskell. In fact, most will tell you it's not needed. The saying "a monad is just a monoid..." is a cliché and an in-joke, not gatekeeping. It's the community having a laugh at itself.
  - jimbob45 4y ago
    I've had someone do that on this very website. I was assured that affine types in Rust are too difficult to understand without a solid grounding in Category Theory. The years have proven that ease of programming and the burden of knowledge are the two most important elements of a programming language. FP zealots simply won't accept that their chosen paradigm is opaque to most for benefits that can't seem to be written out in human language.
    - the_af 4y ago
      > I've had someone do that on this very website On this website you will hear anyone say the wildest assertions. There's the whole human range of expression here. But what makes you think actual FP practitioners (and Haskelers) really believe this? The proof wouldn't be what some random person here on HN tells you. The proof would be you getting involved in an actual FP community trying to write an actual FP project and being told that you just cannot do this unless you understand category theory. Which, as I said, is not something that happens... at least not in my (limited) experience. Never confuse what people tell you here on HN, random forums or even throwaway StackOverflow comments with what actually happens in the actual communities when trying to achieve real goals and not just chat about stuff.
  - AnimalMuppet 4y ago
    But why is it funny? Isn't it funny because the community knows it comes off that way, at least some of the time (and/or some of the people)? > Nobody claims you have to understand category theory to write Haskell. I've seem the claim that you can't really use Haskell without it, here on HN, more than once. (Or at least something that I interpreted as being that claim...)
- wiseowise 4y ago
  > "A monad is just a monoid in the category of endofunctors". Anyone who says that - or anything anywhere close to it - is gatekeeping, no matter how true the statement is. You just tried to badmouth whole community of FP programmers by taking serious a running gag, wow.
- DonaldPShimoda 4y ago
  > "A monad is just a monoid in the category of endofunctors". Anyone who says that - or anything anywhere close to it - is gatekeeping, no matter how true the statement is. The original attribution of this line about monads comes from the (intentionally) comedic article "A Brief, Incomplete, and Mostly Wrong History of Programming Languages", published by James Iry in 2009: http://james-iry.blogspot.com/2009/05/brief-incomplete-and-mostly-wrong.html http://james-iry.blogspot.com/2009/05/brief-incomplete-and-m... It is not a stance I have ever seen taken up in a serious manner by anybody in the FP community, and I work in PL academia (the region of the community from which I would expect to see the most snobbery). Please stop misrepresenting people based on a misunderstood joke. There are people in the FP community who gatekeep and take on a snobbish tone — with that I do not disagree. However, their prevalence is generally overstated; it's a vocal minority situation. Most people I know or have talked to are very welcoming.
  - momentoftop 4y ago
    That article went round the Edinburgh mailing list when it was published, and Phil Wadler, who got monads into Haskell, replied saying something like "I didn't know this. Does anyone have the proof?" The actual quote that monads are monoids in the category of endofunctors comes from MacLane, and is intended for mathematicians.
    - DonaldPShimoda 4y ago
      I'm honestly not sure the MacLane reference applies here. Although the abstract phrasing can be traced to him, the particular use of "just" in the parent comment's quote tells me they're specifically thinking of the (deliberately condescending) version from the Iry post, especially since that's the version that gets memed throughout the FP community. After all, that particular phrasing is meant to convey a sense of "this is obvious and you are stupid if you don't understand it immediately", which is a far cry from the MacLane version (since that one is, as you said, intended for mathematicians). But I probably ought to have included the full provenance regardless; thank you for bringing it up!
      - 4y ago

AnimalMuppet 4y ago

"A monad is just a monoid in the category of endofunctors". Anyone who says that - or anything anywhere close to it - is gatekeeping, no matter how true the statement is. And it's not just the statement. It seems to me (from my outside perspective) that category theory is often used in a gatekeeping way. In contrast, take SQL. How much of the mathematical theory of relations do you need to know to be able to write SQL queries? Yes, it might help, but the SQL gurus don't try to drag you into it every time you get close to a database.

lliamander 4y ago
> "A monad is just a monoid in the category of endofunctors". Anyone who says that - or anything anywhere close to it - is gatekeeping, no matter how true the statement is. Quite frankly, if you don't understand that sentence then you are in no position to judge whether the concepts could be made more accessible. Sometimes the important question is not "could this be easier to learn?" but "is learning it worth the effort?".
Iceland_jack 4y ago
Notions of Computation as Monoids https://www.fceia.unr.edu.ar/~mauro/pubs/Notions_of_Computation_as_Monoids.pdf https://www.fceia.unr.edu.ar/~mauro/pubs/Notions_of_Computat...
packetlost 4y ago
SQL is intrinsically tied to set theory and borrows a ton of terminology and logic from set theory. Whether you understand that it's from mathematics or not doesn't really matter. You are using set theory and it's terminology regardless. I've only really ever seen monoids referred to in Haskell. If you actually read my comment, Haskell is not all FP (no PL is). It's not even a significant portion of FP. So just don't use Haskell, it's hardly the first FP language I would reach for and it's probably not the one you should either. Also, any person willing to learn would be intrigued by the terminology, not reject it as something that's "gatekeeping". Such a defeatist attitude will not get you very far in a field as complex as this.
- tsimionescu 4y ago
  SQL was explicitly designed to appeal to business people, and uses strictly familiar words and phrases. It was very explicitly designed (though I would say it has mostly failed) to read like pseudo-natural language. SQL DBs and the precise semantics of SQL are somewhat based on relational algebra, but SQL syntax is definitely not. It's also not using set theoretic terms in general, with the exception of UNION and INTERSECT.
- TexanFeller 4y ago
  SQL tables are not actually sets at all since you can insert duplicate rows! In practice they usually are though.
  - packetlost 4y ago
    You can't actually insert a complete duplicate row because the ROWID (or whatever your particular RDBMS calls it) is a implicit, but unique property of each row (and corresponds to the offset in the file the row is located at). Further, while tables can be the identity element of all records they contain, they themselves aren't really a set. Usually when people associate set theory with SQL, it's with queries (and their results).
marcosdumay 4y ago
Nobody says that seriously. It tells a lot how people go for common jokes to complain about a community. It's easy to fall for that if you never actually interacted with the people.
the_af 4y ago
Nobody claims you have to understand category theory to write Haskell. In fact, most will tell you it's not needed. The saying "a monad is just a monoid..." is a cliché and an in-joke, not gatekeeping. It's the community having a laugh at itself.
- jimbob45 4y ago
  I've had someone do that on this very website. I was assured that affine types in Rust are too difficult to understand without a solid grounding in Category Theory. The years have proven that ease of programming and the burden of knowledge are the two most important elements of a programming language. FP zealots simply won't accept that their chosen paradigm is opaque to most for benefits that can't seem to be written out in human language.
  - the_af 4y ago
    > I've had someone do that on this very website On this website you will hear anyone say the wildest assertions. There's the whole human range of expression here. But what makes you think actual FP practitioners (and Haskelers) really believe this? The proof wouldn't be what some random person here on HN tells you. The proof would be you getting involved in an actual FP community trying to write an actual FP project and being told that you just cannot do this unless you understand category theory. Which, as I said, is not something that happens... at least not in my (limited) experience. Never confuse what people tell you here on HN, random forums or even throwaway StackOverflow comments with what actually happens in the actual communities when trying to achieve real goals and not just chat about stuff.
- AnimalMuppet 4y ago
  But why is it funny? Isn't it funny because the community knows it comes off that way, at least some of the time (and/or some of the people)? > Nobody claims you have to understand category theory to write Haskell. I've seem the claim that you can't really use Haskell without it, here on HN, more than once. (Or at least something that I interpreted as being that claim...)
wiseowise 4y ago
> "A monad is just a monoid in the category of endofunctors". Anyone who says that - or anything anywhere close to it - is gatekeeping, no matter how true the statement is. You just tried to badmouth whole community of FP programmers by taking serious a running gag, wow.
DonaldPShimoda 4y ago
> "A monad is just a monoid in the category of endofunctors". Anyone who says that - or anything anywhere close to it - is gatekeeping, no matter how true the statement is. The original attribution of this line about monads comes from the (intentionally) comedic article "A Brief, Incomplete, and Mostly Wrong History of Programming Languages", published by James Iry in 2009: http://james-iry.blogspot.com/2009/05/brief-incomplete-and-mostly-wrong.html http://james-iry.blogspot.com/2009/05/brief-incomplete-and-m... It is not a stance I have ever seen taken up in a serious manner by anybody in the FP community, and I work in PL academia (the region of the community from which I would expect to see the most snobbery). Please stop misrepresenting people based on a misunderstood joke. There are people in the FP community who gatekeep and take on a snobbish tone — with that I do not disagree. However, their prevalence is generally overstated; it's a vocal minority situation. Most people I know or have talked to are very welcoming.
- momentoftop 4y ago
  That article went round the Edinburgh mailing list when it was published, and Phil Wadler, who got monads into Haskell, replied saying something like "I didn't know this. Does anyone have the proof?" The actual quote that monads are monoids in the category of endofunctors comes from MacLane, and is intended for mathematicians.
  - DonaldPShimoda 4y ago
    I'm honestly not sure the MacLane reference applies here. Although the abstract phrasing can be traced to him, the particular use of "just" in the parent comment's quote tells me they're specifically thinking of the (deliberately condescending) version from the Iry post, especially since that's the version that gets memed throughout the FP community. After all, that particular phrasing is meant to convey a sense of "this is obvious and you are stupid if you don't understand it immediately", which is a far cry from the MacLane version (since that one is, as you said, intended for mathematicians). But I probably ought to have included the full provenance regardless; thank you for bringing it up!
    - 4y ago