I’ve never worked with Haskell, but I’ve been meaning to expand my programming repertoire (particularly since I don’t get to do much coding at work, let alone learn new languages) and this makes for a nice opportunity, so I wanna try to parse this / guess at the syntax.
I assume iterate function arg
applies some function
to arg
repeatedly, presumably until some exit condition is met? Or does it simply create an infinite, lazily evaluated sequence?
( )
would be an inline function definition then, in this case returning the result of applying ++suffix
to its argument (which other languages might phrase something like arg += suffix
), thereby appending " Is Not an Emulator" to the function argument, which is initially “WINE”.
So as a result, the code would produce an infinite recurring “WINE Is Not an Emulator Is Not an Emulator…” string. If evaluated eagerly, it would result in an OOM error (with tail recursion) or a stack overflow (without). If evaluated lazily, it would produce a lazy string, evaluated only as far as it is queried (by some equivalent of a head
function reading the first X characters from it).
How far off am I? What pieces am I missing?
I think that’s the part I was most confused by. I’m coming mostly from Java and C, where
++
would be the unary operator to increment a number. I would have expected that symbol in a functional language context to be a shorthand for+ 1
. The idea of it being an infix function didn’t occur to me.Partial applications I remember from a class on Clojure I took years ago, but as far as I remember, the functions always had to come first in any given expression. Also, I believe
partial
fills the arguments from the left, so to add a suffix, I’d have to use a reversedstr
function. At that point, it would probably be more idiomatic to just create an inline function to suffix it. So if my distant recollection doesn’t fail me, the Clojure equivalent of that partial function would be#(str % " Is Not an Emulator")
.iterate
works the same though, I think, so the whole expression would be(def wine (iterate #(str % " Is Not an Emulator") "WINE") )
This code was typed on a mobile phone in a quick break based off of years-old memories, so there might be errors, and given it was a single class without ever actually applying it to any problems, I have no real sense for how idiomatic it really is. I’ll gladly take any corrections.
NGL though, that last, readable version is sexy as hell.