A general purpose library offering functional helpers for Golang.
// Find the first 5 even numbers
evens := iter.Count().Filter(filters.IsEven).Take(5).Collect()
reflect.DeepEqual(evens, []int{0, 2, 4, 6, 8})
This library introduces two core concepts, the Iterator
and the Option
.
Using these two concepts this library derives many pre-defined iterators for
use.
The Option
is simply a type that represents the presence or absence of a
value. Options behave somewhat like enumerations with two variants:
Some(value)
and None
.
type Iterator[T any] interface {
Next() option.Option[T]
}
The Iterator
is an interface that defines the behaviour of some type that
"yields" values. Each call to Next()
on an Iterator
will yield another
value as defined by that specific Iterator
. For example, the iterator
iter.Count()
yields 0, 1, 2, 3, etc. and onwards to infinity (or the integer
limit!).
Iterators will yield Some(value)
for as long as they have values to yield.
Iterators that have exhausted all their values will then always yield None
.
This library defines many iterators and a few are demonstrated below. For the entire set simply visit the package documentation.
Here are a few trivial example of what's possible using the iterators in this library.
// All odd natural numbers (1, 3, 5, 7...)
odds := iter.Count().Drop(1).Filter(filters.IsOdd).Collect()
// All lines from a file
lines := iter.CollectResult(iter.LinesString(file)).Unwrap()
// String representations of numbers
numbers := iter.Map(iter.Count(), strconv.Itoa)