4 ms·

I'm not positive on what you are aiming at. I'd assume "algebraic effects" are to talk about performing algebra on the effects. That is, you are specifically

by taeric 1y ago

I'm not positive on what you are aiming at. I'd assume "algebraic effects" are to talk about performing algebra on the effects. That is, you are specifically going to talk about how different things combine effects, preferably in ways that honor + and * that we are used to. If you are just pointing out that this is not, necessarily, "type" related. Agreed. Apologies if I mislead there. I was highlighting that algebraic data types has a similar problem. I did not mean to imply that these were the same topic. My point is simply that there is no value in the program that says an effect has or has not completed. This is why I compare it to stepping through the program. The "line of code" that is active in executing code is not a first class value in your program. It is very much there, of course. But it is not a value of the program.

oisdk 1y ago
> I'd assume "algebraic effects" are to talk about performing algebra on the effects. That is, you are specifically going to talk about how different things combine effects This is a misconception. The "algebra" does not refer to an algebra of effects, or combining effects in any way. It's more like it's the other way around: "algebraic effects" are effects generated from algebras. These algebras are precisely-defined mathematical objects (like groups, monoids, etc.), so you have an "effect" that corresponds to monoids, an "effect" that corresponds to groups, and so on. > My point is simply that there is no value in the program that says an effect has or has not completed. This is why I compare it to stepping through the program. The "line of code" that is active in executing code is not a first class value in your program. I know: I'm trying to say that the "algebra" of "algebraic effects" do refer to first-class values. The + and * from other algebraic operations are the algebraic operations you might use for an algebraic effect.
- taeric 1y ago
  I feel that you just spelled potato and then pronounced it differently. :D If you have examples you recommend, I'd be game to look over them. What is a first class "value" that is referenced in algebraic effects?
  - oisdk 1y ago
    I mean, the program snippet that I gave above contains 3 first-class values. If you write `x = y + z + 0`, or any other statement that uses the group algebra (or any other algebra), you can use algebraic effects to describe the semantics. The “first-class values” here are the x, y, and z: there’s nothing fancy going on. You can even use the group laws to show that the statement is equivalent to `x = y + z` (or whatever). It’s just normal, value-level algebra.
    - taeric 1y ago
      Right, but this is just explaining algebra. Which, I get that. Connect this to effects, for me. (And fair that just because I assert that I get it, I would wager I don't have as strong of a handle as I should have.) My understanding for effects was more like "writes to stdout" and such. Probably better to have "opens a stream," "writes to an open stream," and "closes a stream." The algebra that I typically see is to show that you can combine some of these in such a way to either highlight a bug, or to help prevent them. I got this because many effects typically go through hurdles to find a way to let you log to stderr without it polluting your entire effects system.
      - oisdk 1y ago
        For an algebra, you have some operations and some equations. The group algebra has the + operation, and 0 and -, and all the relevant equations. You can also form an algebra from logging. One operation might be “write to stdout”. And then a law might be `write x; write y = write (x ++ y)` where ++ is string concatenation. This is the algebra, the algebra isn’t for combining effects at all. (Yes, you can combine algebraic effects, and the fact that they’re algebraic does help, but that’s for technical reasons that aren’t relevant) The paper I linked in another comment has a good overview of the topic. It’s really not the kind of thing you can understand from reading a few comments, and the paper is well-written and goes over all of the main points from a pretty basic starting point.
        taeric 1y ago

by taeric 1y ago

oisdk 1y ago

> I'd assume "algebraic effects" are to talk about performing algebra on the effects. That is, you are specifically going to talk about how different things combine effects This is a misconception. The "algebra" does not refer to an algebra of effects, or combining effects in any way. It's more like it's the other way around: "algebraic effects" are effects generated from algebras. These algebras are precisely-defined mathematical objects (like groups, monoids, etc.), so you have an "effect" that corresponds to monoids, an "effect" that corresponds to groups, and so on. > My point is simply that there is no value in the program that says an effect has or has not completed. This is why I compare it to stepping through the program. The "line of code" that is active in executing code is not a first class value in your program. I know: I'm trying to say that the "algebra" of "algebraic effects" do refer to first-class values. The + and * from other algebraic operations are the algebraic operations you might use for an algebraic effect.

taeric 1y ago
I feel that you just spelled potato and then pronounced it differently. :D If you have examples you recommend, I'd be game to look over them. What is a first class "value" that is referenced in algebraic effects?
- oisdk 1y ago
  I mean, the program snippet that I gave above contains 3 first-class values. If you write `x = y + z + 0`, or any other statement that uses the group algebra (or any other algebra), you can use algebraic effects to describe the semantics. The “first-class values” here are the x, y, and z: there’s nothing fancy going on. You can even use the group laws to show that the statement is equivalent to `x = y + z` (or whatever). It’s just normal, value-level algebra.
  - taeric 1y ago
    Right, but this is just explaining algebra. Which, I get that. Connect this to effects, for me. (And fair that just because I assert that I get it, I would wager I don't have as strong of a handle as I should have.) My understanding for effects was more like "writes to stdout" and such. Probably better to have "opens a stream," "writes to an open stream," and "closes a stream." The algebra that I typically see is to show that you can combine some of these in such a way to either highlight a bug, or to help prevent them. I got this because many effects typically go through hurdles to find a way to let you log to stderr without it polluting your entire effects system.
    - oisdk 1y ago
      For an algebra, you have some operations and some equations. The group algebra has the + operation, and 0 and -, and all the relevant equations. You can also form an algebra from logging. One operation might be “write to stdout”. And then a law might be `write x; write y = write (x ++ y)` where ++ is string concatenation. This is the algebra, the algebra isn’t for combining effects at all. (Yes, you can combine algebraic effects, and the fact that they’re algebraic does help, but that’s for technical reasons that aren’t relevant) The paper I linked in another comment has a good overview of the topic. It’s really not the kind of thing you can understand from reading a few comments, and the paper is well-written and goes over all of the main points from a pretty basic starting point.
      - taeric 1y ago