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0 pointsrak15074y ago0 comments

An anonymous function is defined (can't find a better word) between braces like {x+1}, in python (lambda x: x+1). There is an inner one, {x,+/-2#x}, and the outer one (the entire thing).

/ (like a lot of k symbols) does a few different things depending on context. In this case, if you do n f/x, where f takes a single argument (is a unary/monadic function), it applies f to x n times.

-2#x: yeah, it seems reasonable that it might negate the first two elements, APL uses ¯2 instead of -2 for this reason. In k however -2 is parsed as one number, as - then 2#...

Sure, there may be some complexities or questions, but there are in all languages, and in this case they were fairly simple things anyway to me.

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gjulianm4y ago

> here is an inner one, {x,+/-2#x}, and the outer one (the entire thing

So in the inner one, x is the argument of the inner function or the argument of the outer one? Is x always an argument to anonymous functions?

> / (like a lot of k symbols) does a few different things depending on context

That's a recipe for confusion.

> Sure, there may be some complexities or questions, but there are in all languages

I can go back to the initial example: just browse other implementations of Fibonacci in different languages. For most of them you can actually understand a bit what's happening, even if it's a different paradigm (e.g, I can understand the Haskell or Clojure implementations without too many issues, and in fact I can learn things about the language from that). But operators that do different things depending on context, insistence on non-standard symbols, weird scope issues... That's not "complexities or questions that are in all languages", that's a recipe for confusion and extra complexity that you need to have in mind on top of the complexity of whatever you are coding.

rak1507OP4y ago

Default arguments to anonymous functions are x, y, and z. You can also name arguments like this. {[foo; bar] foo+bar} is the same as {x+y}

I'm not denying it is probably more possible to gain a superficial understanding of what code written in other languages does than code written in k to someone who's never seen k before. This just doesn't seem like that important of a language feature. The 'confusion and extra complexity' you mention wouldn't really confuse anyone who'd tried k for more than a couple of hours (at most).

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