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A guideline like "three arguments to a function" says nothing about the type of those three arguments. You are right that there are many jobs that require 8 or

A guideline like "three arguments to a function" says nothing about the type of those three arguments. You are right that there are many jobs that require 8 or more pieces of information, but often those parameters can be grouped into structures which each hold multiple pieces of information. The point is not to create types for every function just to hold their arguments, but that well-thought-out data abstraction can simplify things by factoring data into named structures that are used in multiple functions. For example you could have a drawRectangle function which takes four parameters (x1, y1, x2, y2) of some primitive numeric type, or you could create a Point type and use just two of those. This improves clarity because it is obvious just from the signature of drawRectangle(Point a, Point b) that you are specifying the endpoints of the rectangle, whereas four numeric arguments could mean (x1, y1, x2, y2) or (x, y, width, height).

jblow 9y ago
(a) This kind of thing in many cases is just tedious busywork that you are now making someone do every time they call the routine. What if they have a MyPoint and your procedure takes a YourPoint? And what if your point is 8-dimensional, anyway, what does that constructor look like? (b) This has performance implications, not least because of the ABI. And depending on what language you are using, they can be quite severe (good luck if you are using one of those languages that always puts classes on the heap).
- lmm 9y ago
  > What if they have a MyPoint and your procedure takes a YourPoint? Then you get early warning that you need to be paying attention, rather than silently corrupting your data by swapping some coordinates around. > And what if your point is 8-dimensional, anyway, what does that constructor look like? You don't want an 8-dimensional point literal that takes 8 arguments directly, that's never going to be readable. You might want to use a builder. More likely you want to load it from a data file or something on those lines rather than constructing it directly. Where are you even getting these 8-dimensional points from? > This has performance implications, not least because of the ABI. And depending on what language you are using, they can be quite severe (good luck if you are using one of those languages that always puts classes on the heap). In Haskell (or indeed in C) it doesn't necessarily have performance implications; an 8-element structure may have exactly the same runtime representation as those 8 elements being passed distinctly. (In my experience performance concerns are always overblown in any case. If you have actual performance constraints then profile; if you don't, don't worry about it. Too often performance is used as an excuse)
  - jblow 9y ago
    Then you get early warning that you need to be paying attention, rather than silently corrupting your data by swapping some coordinates around. No, a real-world case is that I have a giant program that uses my own geometric primitives, and now I want to start heavily using a library. I know they are just fricking 3D points or quaternions or whatever. Yet because of some weird ideology you want to increase the amount of gruntwork I have to do, and make my life much less pleasant. You don't want an 8-dimensional point literal that takes 8 arguments directly, that's never going to be readable. You might want to use a builder. More likely you want to load it from a data file or something on those lines rather than constructing it directly. Where are you even getting these 8-dimensional points from? WHAT ARE YOU TALKING ABOUT In Haskell (or indeed in C) it doesn't necessarily have performance implications; an 8-element structure may have exactly the same runtime representation as those 8 elements being passed distinctly. Wow, okay, this conversation is over.
    - codygman 9y ago
      >> In Haskell (or indeed in C) it doesn't necessarily have performance implications; an 8-element structure may have exactly the same runtime representation as those 8 elements being passed distinctly. > Wow, okay, this conversation is over. I'm confused as to why this was a conversation ender. An 8 element structure using newtypes in haskell would have the same runtime. For more info, see: https://skillsmatter.com/skillscasts/5296-safe-zero-cost-coercions-in-haskell https://skillsmatter.com/skillscasts/5296-safe-zero-cost-coe...
      - jblow 9y ago
        It was the "or indeed in C" that ended it for me right there (though that was compounded by the 'you want to load your 8-dimensional points from a file, where else could you possibly be getting them?' stuff, which shows that the correspondent has not done any scientific or geometric programming, or computer graphics, or video games, which are some of the main fields where performance matters most, so if someone is going to make a performance argument ... maybe he should actually know about performance programming). If you want to talk about Haskell, fine ... I don't know anything about Haskell, though, and I am interested in high-performance programming, which is an area where Haskell cannot currently play (nor can any GC'd language). Making claims about how the performance of an operation in a slow language doesn't get any slower under certain circumstances isn't that interesting to me.

jblow 9y ago

(a) This kind of thing in many cases is just tedious busywork that you are now making someone do every time they call the routine. What if they have a MyPoint and your procedure takes a YourPoint? And what if your point is 8-dimensional, anyway, what does that constructor look like? (b) This has performance implications, not least because of the ABI. And depending on what language you are using, they can be quite severe (good luck if you are using one of those languages that always puts classes on the heap).

lmm 9y ago
> What if they have a MyPoint and your procedure takes a YourPoint? Then you get early warning that you need to be paying attention, rather than silently corrupting your data by swapping some coordinates around. > And what if your point is 8-dimensional, anyway, what does that constructor look like? You don't want an 8-dimensional point literal that takes 8 arguments directly, that's never going to be readable. You might want to use a builder. More likely you want to load it from a data file or something on those lines rather than constructing it directly. Where are you even getting these 8-dimensional points from? > This has performance implications, not least because of the ABI. And depending on what language you are using, they can be quite severe (good luck if you are using one of those languages that always puts classes on the heap). In Haskell (or indeed in C) it doesn't necessarily have performance implications; an 8-element structure may have exactly the same runtime representation as those 8 elements being passed distinctly. (In my experience performance concerns are always overblown in any case. If you have actual performance constraints then profile; if you don't, don't worry about it. Too often performance is used as an excuse)
- jblow 9y ago
  Then you get early warning that you need to be paying attention, rather than silently corrupting your data by swapping some coordinates around. No, a real-world case is that I have a giant program that uses my own geometric primitives, and now I want to start heavily using a library. I know they are just fricking 3D points or quaternions or whatever. Yet because of some weird ideology you want to increase the amount of gruntwork I have to do, and make my life much less pleasant. You don't want an 8-dimensional point literal that takes 8 arguments directly, that's never going to be readable. You might want to use a builder. More likely you want to load it from a data file or something on those lines rather than constructing it directly. Where are you even getting these 8-dimensional points from? WHAT ARE YOU TALKING ABOUT In Haskell (or indeed in C) it doesn't necessarily have performance implications; an 8-element structure may have exactly the same runtime representation as those 8 elements being passed distinctly. Wow, okay, this conversation is over.
  - codygman 9y ago
    >> In Haskell (or indeed in C) it doesn't necessarily have performance implications; an 8-element structure may have exactly the same runtime representation as those 8 elements being passed distinctly. > Wow, okay, this conversation is over. I'm confused as to why this was a conversation ender. An 8 element structure using newtypes in haskell would have the same runtime. For more info, see: https://skillsmatter.com/skillscasts/5296-safe-zero-cost-coercions-in-haskell https://skillsmatter.com/skillscasts/5296-safe-zero-cost-coe...
    - jblow 9y ago
      It was the "or indeed in C" that ended it for me right there (though that was compounded by the 'you want to load your 8-dimensional points from a file, where else could you possibly be getting them?' stuff, which shows that the correspondent has not done any scientific or geometric programming, or computer graphics, or video games, which are some of the main fields where performance matters most, so if someone is going to make a performance argument ... maybe he should actually know about performance programming). If you want to talk about Haskell, fine ... I don't know anything about Haskell, though, and I am interested in high-performance programming, which is an area where Haskell cannot currently play (nor can any GC'd language). Making claims about how the performance of an operation in a slow language doesn't get any slower under certain circumstances isn't that interesting to me.