I was working on the pangram exercise on exercism.io, and this was my solution:
from strutils import toLowerAscii
from sequtils import toSeq
import sets
const letters = toSeq("abcdefghijklmnopqrstuvwxyz".items).toSet()
func isPangram*(text: string): bool =
return toSet(toSeq(text.toLowerAscii().items)) >= letters
Run
The thing is, sets doesn't even have a >= operator declared. I can't for the
life of me find where it comes from, because if I try to explicitly import it
from the sets package, it doesn't work.
I decided to rewrite my code to get rid of the missing operator. I also wanted
to be a bit more explicit just to make sure the typing system isn't doing
strange things:
from strutils import toLowerAscii
from sequtils import toSeq
import sets
const letters : HashSet[char] =
toSeq("abcdefghijklmnopqrstuvwxyz".items).toSet()
func isPangram*(text: string): bool =
var mySet : HashSet[char] = toSet(toSeq(text.toLowerAscii().items))
return sets.`<=`(letters, mySet)
Run
So far so good, it still works. And, sets has a <= operator. So it must be
coming from the sets package. I will try to fully qualify everything again:
from strutils import toLowerAscii
from sequtils import toSeq
from sets import HashSet, toSet, `<=`
const letters : HashSet[char] =
toSeq("abcdefghijklmnopqrstuvwxyz".items).toSet()
func isPangram*(text: string): bool =
var mySet : HashSet[char] = toSet(toSeq(text.toLowerAscii().items))
return sets.`<=`(letters, mySet)
Run
And now it doesn't work. mySet and letters are clearly the same type, but the
compiler complains: > C:Appsnim-0.19.4libpurecollectionssets.nim(590, 15)
Error: type mismatch: got <HashSet[system.char]> > but expected one of: >
iterator items[T](s: HSlice[T, T]): T > iterator items(a: cstring): char >
iterator items[T](a: seq[T]): T > iterator items[T](a: openArray[T]): T >
iterator items(a: string): char > iterator items[T](a: set[T]): T > iterator
items(E: typedesc[enum]): E:type > iterator items[IX, T](a: array[IX, T]): T >
> expression: items(s)
I'm quite confused, perhaps someone here could help me. Thank you!
