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twovests OP wrote

Reply to comment by Moonside in Floating point considered harmful (for games) (a rant by 1vs) by twovests

I never even considered time in a server or the whole mess of floats in emulators. I hope to dink nobody is using floats for time.

I also haven't considered about probabilities getting outside the bound of 1, but I still reserve my right to be angery at floats here. grrr floats.

I also have not considered rational numbers, because, wow, they sound very satisfying, and also even less supported, and I want to be their friends, where can I use them,

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Moonside wrote (edited )

I actually first stumbled into rational number data type when I was 12 or 13 and learning Lisp (but that story didn't end well and which totally gave me a misleading view of how principled programming languages were). I think all the major functional languages have them as it's not hard to implement as an abstract data type. A super basic is just a product type of two integers and call one the numerator and the other denominator and implement the operations accordingly.

Even Coq has them and if Coq has something implemented, it's probably pretty widespread in Haskell, Standard ML, OCaml, Scala and various Lisps and what have you.

If you really want some numeric nonsense:

  1. Bad implementations of complex numbers. The rectangular form a + bi is good for sums and re^(iθ) for multiplications. Ideally there should be one type for complex numbers and two classes like data Complex = Rectangular a b | Polar r θ in Haskell. This works ok if there are sum types, but apparently this is too avant garde for most languages.
  2. The Haskell numeric tower makes zero sense and is implemented with type classes, which isn't first class and is antimodular to the extent I recommend beginners only use library defined ones and not make your own like at all for a while at least. Like the Num class for numbers: you need to implement the operations (+), (*), abs, signum, fromInteger, (-) where abs and signum are total party poopers as basically what Num is is a mathematical ring with an extra operation. But, for example, complex numbers don't have a notion of absolute value defined for them so this turns sour quickly. I don't know what would make the situation better, however. They'll never fix this, probably.

Also if you want to read a rant about Booleans... this is pretty good. Every time I'm writing a function that takes a boolean parameter, I split it in two functions or somehow avoid testing for equality in the function. Thus pattern matching is bae and matching constructors is heaven sent. The author's piece on why dynamic languages aren't a thing at all is good too.

Phew, I'm glad that I got all that out of my system!

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twovests OP wrote

Ooh I'm actually learning StandardML for a course of mine! I'll have to read these blog posts later too, I luv rants and I luv booleans so I'll probably love this

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