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## std.ranges: Ranges of integers and other things. For iteration.
## This module is imported by default.
type Range[T] = struct
start: T
end: T
type RangeIncl[T] = struct
start: T
end: T
done: bool
## Exclusive ranges. Useful for iteration.
## Includes `from`, does not include `to`.
pub func ..(from: int, to: int): Range[int] =
{ from, to }
## Inclusive ranges. Useful for ranges.
## Includes `from` and `to`.
pub func ..=(from: int, to: int): RangeIncl[int] =
{ from, to, done: false }
# todo: implement for all types that can increment or smth idk
pub func next[T: int](self: mut Range[T]): T? =
if self.start < self.end then
self.start += 1
Some(self.start - 1)
else
None
# todo: We don't need a mutable Range here to peek.
# How does this interact with classes?
pub func peek[T: int](self: mut Range[T]): T? =
self.peek_nth(0)
pub func peek_nth[T: int](self: mut Range[T], i: uint): T? =
let res = self.start + i
if res < self.end then
return Some(res)
else
return None
pub func next[T: int](self: mut RangeIncl[T]): T? =
if self.done then
None
elif self.start < self.end then
let res = self.start
self.start += 1
Some(res)
elif self.start == self.end then
self.done = true
Some(self.start)
else
self.done = true
None
pub func peek[T: int](self: mut RangeIncl[T]): T? =
self.peek_nth(0)
pub func peek_nth[T: int](self: mut RangeIncl[T], i: uint): T? =
let res = self.start + i
if res <= self.end
then Some(res)
else None
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