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63 lines
1.2 KiB
Go

package span
import (
"constraints"
"github.com/jordanorelli/generic/iter"
)
3 years ago
// Span represents some range of integers
type Span[T constraints.Integer] struct {
Start T
End T
Step T
}
type spanIter[T constraints.Integer] struct {
start T
end T
step T
next T
}
func (s Span[T]) Iter() iter.Ator[T] {
return &spanIter[T]{
start: s.Start,
end: s.End,
step: s.Step,
next: s.Start,
}
}
func (s *spanIter[T]) Next(n *T) bool {
if s.step == 0 || s.next < s.start || s.next >= s.end {
return false
}
*n = s.next
s.next += s.step
return true
}
func (s spanIter[T]) Iter() iter.Ator[T] { return &s }
// New creates a span of integers between start and end. The is analagous to
// the "range" function in Python, but since range already means something in
// Go, span is the chosen name to avoid confusion with Go's concept of range.
// The created span is given a step size of 1.
func New[T constraints.Integer](start, end T) Span[T] {
return Span[T]{
Start: start,
End: end,
Step: 1,
}
}
// Step is the same as creating a span with a provided step value
func Step[T constraints.Integer](start, end, step T) Span[T] {
return Span[T]{
Start: start,
End: end,
Step: step,
}
}