use struct update syntax in with_step()

README.md

@@ -3,7 +3,7 @@
 The `ranges` module provides tools for creating ranges of numbers.
 
 Ranges are represented by the generic `Range` iterator, which has start and
-end points, and a step size.
+end points and a step size.
 
 ```v
 import ranges

ranges.v

@@ -4,7 +4,8 @@ import strconv
 import math.big
 
 struct Range[T] {
-	limit  T
+	start  T
+	end    T
 	step   T
 	is_neg bool
 mut:
@@ -13,7 +14,7 @@ mut:
 
 // next returns the new element from range or none if range end is reached.
 pub fn (mut r Range[T]) next() ?T {
-	if (r.is_neg && r.cur < r.limit) || (!r.is_neg && r.cur > r.limit) {
+	if (r.is_neg && r.cur < r.end) || (!r.is_neg && r.cur > r.end) {
 		return none
 	}
 	defer {
@@ -22,6 +23,21 @@ pub fn (mut r Range[T]) next() ?T {
 	return r.cur
 }
 
+// reset resets the internal iterator state to its initial value, after which the iterator can be reused.
+// Note: `for i in iter {` does not modify the internal iterator state, but direct `next()` call does.
+pub fn (mut r Range[T]) reset() {
+	r.cur = r.start
+}
+
+// with_step returns copy of the range with new step value.
+pub fn (r Range[T]) with_step[T](step T) Range[T] {
+	return Range[T]{
+		...r
+		step: step
+		cur:  r.start
+	}
+}
+
 // range creates new Range iterator with given start, end and step values.
 //
 // Generally numbers are expected. If type is a struct the following operators
@@ -33,7 +49,8 @@ pub fn (mut r Range[T]) next() ?T {
 // Note: Zero step value will cause an infitite loop!
 pub fn range[T](start T, end T, step T) Range[T] {
 	return Range[T]{
-		limit:  end
+		start:  start
+		end:    end
 		step:   step
 		cur:    start
 		is_neg: start > end
@@ -52,7 +69,7 @@ pub:
 // Use from_string_custom if you want to use custom type with special string
 // convertion rules.
 //
-// Supported string formats are `start-end`, `start[:step]end`. start and end
+// Supported string formats are `start-end` and `start[:step]end`. start and end
 // values are sepatared by 'sep' which is hypen (`-`) by default. Single number
 // will be interpreted as range of one element. Several ranges can be specified
 // in a line, separated by 'group_sep' (comma by default). 'sep' and 'group_sep'

ranges_test.v

@@ -145,3 +145,36 @@ fn test_range_from_string_custom_type() {
 		sep: '..'
 	)! == [ranges.range[Int](Int{0}, Int{10}, Int{1})]
 }
+
+fn test_range_reset() {
+	mut result := []int{}
+	mut iter := ranges.range(0, 5, 1)
+
+	for {
+		if elem := iter.next() {
+			result << elem
+		} else {
+			break
+		}
+	}
+	assert result == [0, 1, 2, 3, 4, 5]
+
+	iter.reset()
+
+	result = []int{}
+
+	for i in iter {
+		result << i
+	}
+	assert result == [0, 1, 2, 3, 4, 5]
+}
+
+fn test_range_new_with_step() {
+	mut result := []int{}
+	mut iter := ranges.range(0, 5, 1)
+
+	for i in iter.with_step(2) {
+		result << i
+	}
+	assert result == [0, 2, 4]
+}

v.mod

@@ -1,7 +1,7 @@
 Module {
 	name: 'ranges'
 	description: 'Operating with ranges of numbers'
-	version: '0.2.0'
+	version: '0.3.0'
 	license: 'Unlicense'
 	dependencies: []
 }