rand: simplify rand.PRNG, move to optional types for error handling (#13570)

cmd/tools/bench/wyhash.v

@@ -16,11 +16,11 @@ fn main() {
 	mut bgenerating := benchmark.start()
 	mut bytepile := []byte{}
 	for _ in 0 .. sample_size * max_str_len {
-		bytepile << byte(rand.int_in_range(40, 125))
+		bytepile << byte(rand.int_in_range(40, 125) or { 40 })
 	}
 	mut str_lens := []int{}
 	for _ in 0 .. sample_size {
-		str_lens << rand.int_in_range(min_str_len, max_str_len)
+		str_lens << rand.int_in_range(min_str_len, max_str_len) or { min_str_len }
 	}
 	bgenerating.measure('generating strings')
 	println('Hashing each of the generated strings...')

cmd/tools/fuzz/map_fuzz.v

@@ -10,9 +10,9 @@ fn generate_strings(str_len int, arr_len int) []string {
 }
 
 fn fuzz1() {
-	amount := 200000 - rand.intn(100000)
+	amount := 200000 - rand.intn(100000) or { 0 }
-	amount2 := 200000 - rand.intn(100000)
+	amount2 := 200000 - rand.intn(100000) or { 0 }
-	len := 25 - rand.intn(10)
+	len := 25 - rand.intn(10) or { 0 }
 	arr := generate_strings(len, amount)
 	arr2 := generate_strings(len, amount2)
 	mut m := map[string]int{}
@@ -34,8 +34,8 @@ fn fuzz1() {
 
 fn fuzz2() {
 	mut m := map[string]int{}
-	amount := rand.intn(500000) + 1
+	amount := rand.intn(500000) or { 0 } + 1
-	len := 25 - rand.intn(10)
+	len := 25 - rand.intn(10) or { 0 }
 	arr := generate_strings(len, amount)
 	for i, x in arr {
 		m[x] = i
@@ -54,8 +54,8 @@ fn fuzz2() {
 
 fn fuzz3() {
 	mut m := map[string]int{}
-	amount := rand.intn(500000) + 1
+	amount := rand.intn(500000) or { 0 } + 1
-	len := 25 - rand.intn(10)
+	len := 25 - rand.intn(10) or { 0 }
 	arr := generate_strings(len, amount)
 	for i, x in arr {
 		if (i % 10000) == 0 {
@@ -74,8 +74,8 @@ fn fuzz3() {
 }
 
 fn fuzz4() {
-	amount := rand.intn(500000)
+	amount := rand.intn(500000) or { 0 }
-	len := 25 - rand.intn(10)
+	len := 25 - rand.intn(10) or { 0 }
 	arr := generate_strings(len, amount)
 	mut m := map[string]int{}
 	for i in 0 .. amount {
@@ -93,7 +93,7 @@ fn fuzz4() {
 }
 
 fn fuzz5() {
-	amount := rand.intn(500000) + 1
+	amount := rand.intn(500000) or { 0 } + 1
 	arr := generate_strings(20, amount)
 	mut m := map[string]int{}
 	for i in 0 .. amount {
@@ -114,8 +114,8 @@ fn fuzz5() {
 
 fn fuzz6() {
 	mut m := map[string]int{}
-	amount := rand.intn(500000) + 1
+	amount := rand.intn(500000) or { 0 } + 1
-	len := 25 - rand.intn(10)
+	len := 25 - rand.intn(10) or { 0 }
 	arr := generate_strings(len, amount)
 	for i, x in arr {
 		m[x]++

examples/2048/2048.v

@@ -390,10 +390,11 @@ fn (mut b Board) place_random_tile() (Pos, int) {
 		}
 	}
 	if empty_tiles_max > 0 {
-		new_random_tile_index := rand.intn(empty_tiles_max)
+		new_random_tile_index := rand.intn(empty_tiles_max) or { 0 }
 		empty_pos := etiles[new_random_tile_index]
 		// 10% chance of getting a `4` tile
-		random_value := if rand.f64n(1.0) < 0.9 { 1 } else { 2 }
+		value := rand.f64n(1.0) or { 0.0 }
+		random_value := if value < 0.9 { 1 } else { 2 }
 		b.field[empty_pos.y][empty_pos.x] = random_value
 		return empty_pos, random_value
 	}
@@ -465,7 +466,7 @@ fn (mut app App) ai_move() {
 			cboard.place_random_tile()
 			mut cmoves := 0
 			for !cboard.is_game_over() {
-				nmove := possible_moves[rand.intn(possible_moves.len)]
+				nmove := possible_moves[rand.intn(possible_moves.len) or { 0 }]
 				cboard, is_valid = cboard.move(nmove)
 				if !is_valid {
 					continue

examples/fireworks/fireworks.v

@@ -32,7 +32,7 @@ fn on_frame(mut app App) {
 	}
 
 	// chance of firing new rocket
-	if rand.intn(30) == 0 {
+	if rand.intn(30) or { 0 } == 0 {
 		app.rockets << objects.new_rocket()
 	}
 	// simulating rockets

examples/fireworks/modules/objects/color.v

@@ -5,8 +5,8 @@ import rand
 
 pub fn random_color() gx.Color {
 	return gx.Color{
-		r: byte(rand.int_in_range(0, 256))
+		r: rand.byte()
-		g: byte(rand.int_in_range(0, 256))
+		g: rand.byte()
-		b: byte(rand.int_in_range(0, 256))
+		b: rand.byte()
 	}
 }

examples/fireworks/modules/objects/rocket.v

@@ -51,11 +51,11 @@ pub fn new_rocket() Rocket {
 	return Rocket{
 		color: random_color()
 		pos: Vector{
-			x: rand.f32_in_range(50, get_params().width - 50)
+			x: rand.f32_in_range(50, get_params().width - 50) or { 50 }
 		}
 		vel: Vector{
-			x: rand.f32_in_range(-1.5, 1.5)
+			x: rand.f32_in_range(-1.5, 1.5) or { -1.5 }
-			y: rand.f32_in_range(5, 7)
+			y: rand.f32_in_range(5, 7) or { 5 }
 		}
 	}
 }

examples/fireworks/modules/objects/vector.v

@@ -18,7 +18,7 @@ pub fn (vector Vector) mult(scalar f32) Vector {
 }
 
 pub fn random_vector_in_circle() Vector {
-	theta := rand.f32n(2 * math.pi)
+	theta := rand.f32n(2 * math.pi) or { 0 }
 	y := rand.f32()
 
 	return Vector{

examples/gg/stars.v

@@ -60,22 +60,22 @@ fn main() {
 		user_data: app
 	)
 	for i in 0 .. max_stars {
-		app.stars[i].x = rand.f32_in_range(-200.0, 200.0)
+		app.stars[i].x = rand.f32_in_range(-200.0, 200.0) or { -200.0 }
-		app.stars[i].y = rand.f32_in_range(-200.0, 200.0)
+		app.stars[i].y = rand.f32_in_range(-200.0, 200.0) or { -200.0 }
-		app.stars[i].z = rand.f32_in_range(-200.0, -100.0)
+		app.stars[i].z = rand.f32_in_range(-200.0, -100.0) or { -200.0 }
-		app.stars[i].r = rand.f32_in_range(0.1, 1.0)
+		app.stars[i].r = rand.f32_in_range(0.1, 1.0) or { 0.1 }
-		app.stars[i].g = rand.f32_in_range(0.1, 1.0)
+		app.stars[i].g = rand.f32_in_range(0.1, 1.0) or { 0.1 }
-		app.stars[i].b = rand.f32_in_range(0.1, 1.0)
+		app.stars[i].b = rand.f32_in_range(0.1, 1.0) or { 0.1 }
 	}
 	for i in 0 .. max_v_letters {
-		app.v_letters[i].x = rand.f32_in_range(-20.0, 20.0)
+		app.v_letters[i].x = rand.f32_in_range(-20.0, 20.0) or { -20.0 }
-		app.v_letters[i].y = rand.f32_in_range(-20.0, 20.0)
+		app.v_letters[i].y = rand.f32_in_range(-20.0, 20.0) or { -20.0 }
-		app.v_letters[i].z = rand.f32_in_range(-5.0, -1.0)
+		app.v_letters[i].z = rand.f32_in_range(-5.0, -1.0) or { -5.0 }
-		app.v_letters[i].w = rand.f32_in_range(5, 20)
+		app.v_letters[i].w = rand.f32_in_range(5, 20) or { 5 }
 		app.v_letters[i].h = app.v_letters[i].w
-		app.v_letters[i].angle = rand.f32_in_range(0, 6.283184)
+		app.v_letters[i].angle = rand.f32_in_range(0, 6.283184) or { 0 }
-		app.v_letters[i].dangle = rand.f32_in_range(-0.05, 0.05)
+		app.v_letters[i].dangle = rand.f32_in_range(-0.05, 0.05) or { -0.05 }
-		app.v_letters[i].dz = rand.f32_in_range(-0.1, -0.01)
+		app.v_letters[i].dz = rand.f32_in_range(-0.1, -0.01) or { -0.1 }
 	}
 	app.gg.run()
 }
@@ -102,9 +102,9 @@ fn (mut app App) draw() {
 		sgl.v3f_c3f(s.x, s.y, s.z, s.r, s.g, s.b)
 		app.stars[i].z += 0.3
 		if app.stars[i].z > -1.0 {
-			app.stars[i].x = rand.f32_in_range(-200.0, 200.0)
+			app.stars[i].x = rand.f32_in_range(-200.0, 200.0) or { -200.0 }
-			app.stars[i].y = rand.f32_in_range(-200.0, 200.0)
+			app.stars[i].y = rand.f32_in_range(-200.0, 200.0) or { -200.0 }
-			app.stars[i].z = rand.f32_in_range(-200.0, -100.0)
+			app.stars[i].z = rand.f32_in_range(-200.0, -100.0) or { -200.0 }
 		}
 	}
 	sgl.end()
@@ -119,15 +119,15 @@ fn (mut app App) draw() {
 		app.v_letters[i].z += app.v_letters[i].dz
 		app.v_letters[i].angle += app.v_letters[i].dangle
 		if app.v_letters[i].z > -60.0 {
-			app.v_letters[i].x += rand.f32_in_range(-0.05, 0.05)
+			app.v_letters[i].x += rand.f32_in_range(-0.05, 0.05) or { -0.05 }
-			app.v_letters[i].y += rand.f32_in_range(-0.05, 0.05)
+			app.v_letters[i].y += rand.f32_in_range(-0.05, 0.05) or { -0.05 }
 		}
 		if app.v_letters[i].z < -95.0 {
 			app.v_letters[i].h *= 0.8
 			app.v_letters[i].w *= 0.8
 		}
 		if app.v_letters[i].z < -100.0 {
-			app.v_letters[i].z = rand.f32_in_range(-5.0, -1.0)
+			app.v_letters[i].z = rand.f32_in_range(-5.0, -1.0) or { -5.0 }
 			app.v_letters[i].h = 10.0
 			app.v_letters[i].w = 10.0
 		}

examples/quick_sort.v

@@ -8,7 +8,7 @@ const (
 fn main() {
 	mut arr := []int{}
 	for _ in 0 .. gen_len {
-		arr << rand.intn(gen_max)
+		arr << rand.intn(gen_max) or { 0 }
 	}
 	println('length of random array is $arr.len')
 	println('before quick sort whether array is sorted: ${is_sorted<int>(arr)}')

examples/rule110.v

@@ -33,7 +33,7 @@ fn main() {
 
 	mut generation_bin := []int{len: n}
 	for i in 0 .. n {
-		generation_bin[i] = rand.intn(2)
+		generation_bin[i] = rand.intn(2) or { 0 }
 	}
 	print('\n')
 

examples/snek/snek.js.v

@@ -64,8 +64,8 @@ fn (mut app App) reset_game() {
 
 fn (mut app App) move_food() {
 	for {
-		x := rand.int_in_range(0, game_size)
+		x := rand.intn(game_size) or { 0 }
-		y := rand.int_in_range(0, game_size)
+		y := rand.intn(game_size) or { 0 }
 		app.food = Pos{x, y}
 
 		if app.food !in app.snake {

examples/snek/snek.v

@@ -79,8 +79,8 @@ fn (mut app App) reset_game() {
 
 fn (mut app App) move_food() {
 	for {
-		x := rand.int_in_range(0, game_size)
+		x := rand.intn(game_size) or { 0 }
-		y := rand.int_in_range(0, game_size)
+		y := rand.intn(game_size) or { 0 }
 		app.food = Pos{x, y}
 
 		if app.food !in app.snake {

examples/sokol/particles/modules/particle/system.v

@@ -68,10 +68,11 @@ pub fn (mut s System) explode(x f32, y f32) {
 		p = s.bin[i]
 		p.reset()
 		p.location.from(center)
-		p.acceleration = vec2.Vec2{rand.f32_in_range(-0.5, 0.5), rand.f32_in_range(-0.5,
+		p.acceleration = vec2.Vec2{rand.f32_in_range(-0.5, 0.5) or { -0.5 }, rand.f32_in_range(-0.5,
-			0.5)}
+			0.5) or { -0.5 }}
-		p.velocity = vec2.Vec2{rand.f32_in_range(-0.5, 0.5), rand.f32_in_range(-0.5, 0.5)}
+		p.velocity = vec2.Vec2{rand.f32_in_range(-0.5, 0.5) or { -0.5 }, rand.f32_in_range(-0.5,
-		p.life_time = rand.f64_in_range(500, 2000)
+			0.5) or { -0.5 }}
+		p.life_time = rand.f64_in_range(500, 2000) or { 500 }
 		s.pool << p
 		s.bin.delete(i)
 		reserve--

examples/term.ui/rectangles.v

@@ -21,9 +21,9 @@ mut:
 
 fn random_color() tui.Color {
 	return tui.Color{
-		r: byte(rand.intn(256))
+		r: rand.byte()
-		g: byte(rand.intn(256))
+		g: rand.byte()
-		b: byte(rand.intn(256))
+		b: rand.byte()
 	}
 }
 

examples/term.ui/vyper.v

@@ -53,8 +53,8 @@ fn (v Vec) facing() Orientation {
 
 // generate a random vector with x in [min_x, max_x] and y in [min_y, max_y]
 fn (mut v Vec) randomize(min_x int, min_y int, max_x int, max_y int) {
-	v.x = rand.int_in_range(min_x, max_x)
+	v.x = rand.int_in_range(min_x, max_x) or { min_x }
-	v.y = rand.int_in_range(min_y, max_y)
+	v.y = rand.int_in_range(min_y, max_y) or { min_y }
 }
 
 // part of snake's body representation
@@ -192,8 +192,8 @@ fn (mut s Snake) randomize() {
 	for pos.x % 2 != 0 || (pos.x < buffer && pos.x > s.app.width - buffer) {
 		pos.randomize(buffer, buffer, s.app.width - buffer, s.app.height - buffer)
 	}
-	s.velocity.y = rand.int_in_range(-1 * block_size, block_size)
+	s.velocity.y = rand.int_in_range(-1 * block_size, block_size) or { 0 }
-	s.velocity.x = speeds[rand.intn(speeds.len)]
+	s.velocity.x = speeds[rand.intn(speeds.len) or { 0 }]
 	s.direction = s.velocity.facing()
 	s.body[0].pos = pos
 }

examples/tetris/tetris.js.v

@@ -179,7 +179,7 @@ fn main() {
 
 fn (mut g Game) init_game() {
 	g.parse_tetros()
-	g.next_tetro_idx = rand.intn(b_tetros.len) // generate initial "next"
+	g.next_tetro_idx = rand.intn(b_tetros.len) or { 0 } // generate initial "next"
 	g.generate_tetro()
 	g.field = []
 	// Generate the field, fill it with 0's, add -1's on each edge
@@ -307,7 +307,7 @@ fn (mut g Game) generate_tetro() {
 	g.pos_y = 0
 	g.pos_x = field_width / 2 - tetro_size / 2
 	g.tetro_idx = g.next_tetro_idx
-	g.next_tetro_idx = rand.intn(b_tetros.len)
+	g.next_tetro_idx = rand.intn(b_tetros.len) or { 0 }
 	g.rotation_idx = 0
 	g.get_tetro()
 }

examples/tetris/tetris.v

@@ -183,7 +183,7 @@ fn main() {
 
 fn (mut g Game) init_game() {
 	g.parse_tetros()
-	g.next_tetro_idx = rand.intn(b_tetros.len) // generate initial "next"
+	g.next_tetro_idx = rand.intn(b_tetros.len) or { 0 } // generate initial "next"
 	g.generate_tetro()
 	g.field = []
 	// Generate the field, fill it with 0's, add -1's on each edge
@@ -311,7 +311,7 @@ fn (mut g Game) generate_tetro() {
 	g.pos_y = 0
 	g.pos_x = field_width / 2 - tetro_size / 2
 	g.tetro_idx = g.next_tetro_idx
-	g.next_tetro_idx = rand.intn(b_tetros.len)
+	g.next_tetro_idx = rand.intn(b_tetros.len) or { 0 }
 	g.rotation_idx = 0
 	g.get_tetro()
 }

examples/vcasino/vcasino.v

@@ -91,7 +91,7 @@ fn get_bet(money int) int {
 
 fn run_wheel(bet_nbr int, _bet int) int {
 	mut bet := _bet
-	winning_nbr := rand.intn(50)
+	winning_nbr := rand.intn(50) or { 0 }
 	print('Roulette Wheel spinning... and stops on the number $winning_nbr which is a ')
 	if winning_nbr % 2 == 1 {
 		println(odd)

examples/vweb/vweb_example.v

@@ -25,7 +25,7 @@ fn main() {
 
 ['/users/:user']
 pub fn (mut app App) user_endpoint(user string) vweb.Result {
-	id := rand.intn(100)
+	id := rand.intn(100) or { 0 }
 	return app.json({
 		user: id
 	})

vlib/bitfield/bitfield_test.v

@@ -36,10 +36,10 @@ fn test_bf_and_not_or_xor() {
 	mut input2 := bitfield.new(len)
 	mut i := 0
 	for i < len {
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input1.set_bit(i)
 		}
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input2.set_bit(i)
 		}
 		i++
@@ -62,7 +62,7 @@ fn test_clone_cmp() {
 	len := 80
 	mut input := bitfield.new(len)
 	for i in 0 .. len {
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input.set_bit(i)
 		}
 	}
@@ -75,7 +75,7 @@ fn test_slice_join() {
 	len := 80
 	mut input := bitfield.new(len)
 	for i in 0 .. len {
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input.set_bit(i)
 		}
 	}
@@ -98,7 +98,7 @@ fn test_pop_count() {
 	mut count0 := 0
 	mut input := bitfield.new(len)
 	for i in 0 .. len {
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input.set_bit(i)
 			count0++
 		}
@@ -113,7 +113,7 @@ fn test_hamming() {
 	mut input1 := bitfield.new(len)
 	mut input2 := bitfield.new(len)
 	for i in 0 .. len {
-		match rand.intn(4) {
+		match rand.intn(4) or { 0 } {
 			0, 1 {
 				input1.set_bit(i)
 				count++
@@ -152,7 +152,7 @@ fn test_bf_from_str() {
 	len := 80
 	mut input := ''
 	for _ in 0 .. len {
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input = input + '1'
 		} else {
 			input = input + '0'
@@ -172,7 +172,7 @@ fn test_bf_bf2str() {
 	len := 80
 	mut input := bitfield.new(len)
 	for i in 0 .. len {
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input.set_bit(i)
 		}
 	}
@@ -211,7 +211,7 @@ fn test_bf_clear_all() {
 	len := 80
 	mut input := bitfield.new(len)
 	for i in 0 .. len {
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input.set_bit(i)
 		}
 	}
@@ -229,7 +229,7 @@ fn test_bf_reverse() {
 	len := 80
 	mut input := bitfield.new(len)
 	for i in 0 .. len {
-		if rand.intn(2) == 1 {
+		if rand.intn(2) or { 0 } == 1 {
 			input.set_bit(i)
 		}
 	}
@@ -246,9 +246,9 @@ fn test_bf_reverse() {
 
 fn test_bf_resize() {
 	len := 80
-	mut input := bitfield.new(rand.intn(len) + 1)
+	mut input := bitfield.new(rand.intn(len) or { 0 } + 1)
 	for _ in 0 .. 100 {
-		input.resize(rand.intn(len) + 1)
+		input.resize(rand.intn(len) or { 0 } + 1)
 		input.set_bit(input.get_size() - 1)
 	}
 	assert input.get_bit(input.get_size() - 1) == 1
@@ -272,12 +272,12 @@ fn test_bf_pos() {
 			mut needle := bitfield.new(i)
 			// fill the needle with random values
 			for k in 0 .. i {
-				if rand.intn(2) == 1 {
+				if rand.intn(2) or { 0 } == 1 {
 					needle.set_bit(k)
 				}
 			}
 			// make sure the needle contains at least one set bit, selected randomly
-			r := rand.intn(i)
+			r := rand.intn(i) or { 0 }
 			needle.set_bit(r)
 			// create the haystack, make sure it contains the needle
 			mut haystack := needle.clone()
@@ -323,7 +323,7 @@ fn test_bf_printing() {
 	len := 80
 	mut input := bitfield.new(len)
 	for i in 0 .. len {
-		if rand.intn(2) == 0 {
+		if rand.intn(2) or { 0 } == 0 {
 			input.set_bit(i)
 		}
 	}

vlib/crypto/ed25519/internal/edwards25519/element_test.v

@@ -82,16 +82,16 @@ const (
 
 fn generate_weird_field_element() Element {
 	return Element{
-		l0: edwards25519.weird_limbs_52[rand.intn(edwards25519.weird_limbs_52.len)]
+		l0: edwards25519.weird_limbs_52[rand.intn(edwards25519.weird_limbs_52.len) or { 0 }]
-		l1: edwards25519.weird_limbs_51[rand.intn(edwards25519.weird_limbs_51.len)]
+		l1: edwards25519.weird_limbs_51[rand.intn(edwards25519.weird_limbs_51.len) or { 0 }]
-		l2: edwards25519.weird_limbs_51[rand.intn(edwards25519.weird_limbs_51.len)]
+		l2: edwards25519.weird_limbs_51[rand.intn(edwards25519.weird_limbs_51.len) or { 0 }]
-		l3: edwards25519.weird_limbs_51[rand.intn(edwards25519.weird_limbs_51.len)]
+		l3: edwards25519.weird_limbs_51[rand.intn(edwards25519.weird_limbs_51.len) or { 0 }]
-		l4: edwards25519.weird_limbs_51[rand.intn(edwards25519.weird_limbs_51.len)]
+		l4: edwards25519.weird_limbs_51[rand.intn(edwards25519.weird_limbs_51.len) or { 0 }]
 	}
 }
 
 fn (e Element) generate_element() Element {
-	if rand.intn(2) == 0 {
+	if rand.intn(2) or { 0 } == 0 {
 		return generate_weird_field_element()
 	}
 	return generate_field_element()

vlib/crypto/ed25519/internal/edwards25519/scalar.v

@@ -1099,7 +1099,7 @@ fn generate_scalar(size int) ?Scalar {
 	return reflect.ValueOf(s)
 	*/
 	mut s := edwards25519.sc_zero
-	diceroll := rand.intn(100)
+	diceroll := rand.intn(100) or {0}
 	match true {
 		/*
 		case diceroll == 0:

vlib/io/util/util.v

@@ -75,7 +75,7 @@ pub fn temp_dir(tdo TempFileOptions) ?string {
 
 // * Utility functions
 fn random_number() string {
-	s := (1_000_000_000 + (u32(os.getpid()) + rand.u32n(1_000_000_000))).str()
+	s := (1_000_000_000 + (u32(os.getpid()) + rand.u32n(1_000_000_000) or { 0 })).str()
 	return s.substr(1, s.len)
 }
 

vlib/math/big/division_array_ops_test.v

@@ -142,7 +142,7 @@ fn random_number(length int) Integer {
 	numbers := '0123456789'
 	mut stri := ''
 	for _ in 0 .. length {
-		i := rand.intn(10)
+		i := rand.intn(10) or { 0 }
 		nr := numbers[i]
 		stri = stri + nr.ascii_str()
 	}

vlib/net/websocket/utils.v

@@ -20,7 +20,7 @@ fn htonl64(payload_len u64) []byte {
 
 // create_masking_key returs a new masking key to use when masking websocket messages
 fn create_masking_key() []byte {
-	mask_bit := byte(rand.intn(255))
+	mask_bit := rand.byte()
 	buf := []byte{len: 4, init: `0`}
 	unsafe { C.memcpy(buf.data, &mask_bit, 4) }
 	return buf
@@ -48,7 +48,7 @@ fn get_nonce(nonce_size int) string {
 	mut nonce := []byte{len: nonce_size, cap: nonce_size}
 	alphanum := '0123456789ABCDEFGHIJKLMNOPQRSTUVXYZabcdefghijklmnopqrstuvwxyz'
 	for i in 0 .. nonce_size {
-		nonce[i] = alphanum[rand.intn(alphanum.len)]
+		nonce[i] = alphanum[rand.intn(alphanum.len) or { 0 }]
 	}
 	return unsafe { tos(nonce.data, nonce.len) }.clone()
 }

vlib/net/websocket/websocket_test.v

@@ -21,7 +21,7 @@ fn test_ws_ipv6() {
 	if should_skip {
 		return
 	}
-	port := 30000 + rand.intn(1024)
+	port := 30000 + rand.intn(1024) or { 0 }
 	go start_server(.ip6, port)
 	time.sleep(500 * time.millisecond)
 	ws_test(.ip6, 'ws://localhost:$port') or { assert false }
@@ -32,7 +32,7 @@ fn test_ws_ipv4() {
 	if should_skip {
 		return
 	}
-	port := 30000 + rand.intn(1024)
+	port := 30000 + rand.intn(1024) or { 0 }
 	go start_server(.ip, port)
 	time.sleep(500 * time.millisecond)
 	ws_test(.ip, 'ws://localhost:$port') or { assert false }

vlib/rand/dist/dist.v

@@ -49,8 +49,8 @@ pub fn normal_pair(config NormalConfigStruct) (f64, f64) {
 	// See: https://doi.org/10.1137%2F1006063
 	// Also: https://en.wikipedia.org/wiki/Marsaglia_polar_method
 	for {
-		u := rand.f64_in_range(-1, 1)
+		u := rand.f64_in_range(-1, 1) or { 0.0 }
-		v := rand.f64_in_range(-1, 1)
+		v := rand.f64_in_range(-1, 1) or { 0.0 }
 
 		s := u * u + v * v
 		if s >= 1 || s == 0 {

vlib/rand/mt19937/mt19937.v

@@ -3,8 +3,6 @@
 // that can be found in the LICENSE file.
 module mt19937
 
-import math.bits
-
 /*
 C++ functions for MT19937, with initialization improved 2002/2/10.
    Coded by Takuji Nishimura and Makoto Matsumoto.
@@ -133,197 +131,6 @@ pub fn (mut rng MT19937RNG) u64() u64 {
 	return x
 }
 
-// int returns a 32-bit signed (possibly negative) `int`.
-[inline]
-pub fn (mut rng MT19937RNG) int() int {
-	return int(rng.u32())
-}
-
-// i64 returns a 64-bit signed (possibly negative) `i64`.
-[inline]
-pub fn (mut rng MT19937RNG) i64() i64 {
-	return i64(rng.u64())
-}
-
-// int31 returns a 31bit positive pseudorandom `int`.
-[inline]
-pub fn (mut rng MT19937RNG) int31() int {
-	return int(rng.u32() >> 1)
-}
-
-// int63 returns a 63bit positive pseudorandom `i64`.
-[inline]
-pub fn (mut rng MT19937RNG) int63() i64 {
-	return i64(rng.u64() >> 1)
-}
-
-// u32n returns a 32bit `u32` in range `[0, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) u32n(max u32) u32 {
-	if max == 0 {
-		eprintln('max must be positive integer.')
-		exit(1)
-	}
-	// Check SysRNG in system_rng.c.v for explanation
-	bit_len := bits.len_32(max)
-	if bit_len == 32 {
-		for {
-			value := rng.u32()
-			if value < max {
-				return value
-			}
-		}
-	} else {
-		mask := (u32(1) << (bit_len + 1)) - 1
-		for {
-			value := rng.u32() & mask
-			if value < max {
-				return value
-			}
-		}
-	}
-	return u32(0)
-}
-
-// u64n returns a 64bit `u64` in range `[0, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) u64n(max u64) u64 {
-	if max == 0 {
-		eprintln('max must be positive integer.')
-		exit(1)
-	}
-	bit_len := bits.len_64(max)
-	if bit_len == 64 {
-		for {
-			value := rng.u64()
-			if value < max {
-				return value
-			}
-		}
-	} else {
-		mask := (u64(1) << (bit_len + 1)) - 1
-		for {
-			value := rng.u64() & mask
-			if value < max {
-				return value
-			}
-		}
-	}
-	return u64(0)
-}
-
-// u32n returns a pseudorandom `u32` value that is guaranteed to be in range `[min, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) u32_in_range(min u32, max u32) u32 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.u32n(max - min)
-}
-
-// u64n returns a pseudorandom `u64` value that is guaranteed to be in range `[min, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) u64_in_range(min u64, max u64) u64 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.u64n(max - min)
-}
-
-// intn returns a 32bit positive `int` in range `[0, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) intn(max int) int {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return int(rng.u32n(u32(max)))
-}
-
-// i64n returns a 64bit positive `i64` in range `[0, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) i64n(max i64) i64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return i64(rng.u64n(u64(max)))
-}
-
-// int_in_range returns a 32bit positive `int` in range `[min, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) int_in_range(min int, max int) int {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.intn(max - min)
-}
-
-// i64_in_range returns a 64bit positive `i64` in range `[min, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) i64_in_range(min i64, max i64) i64 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.i64n(max - min)
-}
-
-// f32 returns a 32bit real (`f32`) in range `[0, 1)`.
-[inline]
-pub fn (mut rng MT19937RNG) f32() f32 {
-	return f32(rng.f64())
-}
-
-// f64 returns 64bit real (`f64`) in range `[0, 1)`.
-[inline]
-pub fn (mut rng MT19937RNG) f64() f64 {
-	return f64(rng.u64() >> 11) * mt19937.inv_f64_limit
-}
-
-// f32n returns a 32bit real (`f32`) in range [0, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) f32n(max f32) f32 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f32() * max
-}
-
-// f64n returns a 64bit real (`f64`) in range `[0, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) f64n(max f64) f64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f64() * max
-}
-
-// f32_in_range returns a pseudorandom `f32` that lies in range `[min, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) f32_in_range(min f32, max f32) f32 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.f32n(max - min)
-}
-
-// i64_in_range returns a pseudorandom `i64` that lies in range `[min, max)`.
-[inline]
-pub fn (mut rng MT19937RNG) f64_in_range(min f64, max f64) f64 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.f64n(max - min)
-}
-
 // free should be called when the generator is no longer needed
 [unsafe]
 pub fn (mut rng MT19937RNG) free() {

vlib/rand/mt19937/mt19937_test.v

@@ -1,4 +1,5 @@
 import math
+import rand
 import rand.mt19937
 import rand.seed
 
@@ -15,7 +16,7 @@ const (
 )
 
 fn mt19937_basic_test() {
-	mut rng := mt19937.MT19937RNG{}
+	mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 	rng.seed([u32(0xdeadbeef)])
 	target := [u32(956529277), 3842322136, 3319553134, 1843186657, 2704993644, 595827513, 938518626,
 		1676224337, 3221315650, 1819026461]
@@ -27,10 +28,11 @@ fn mt19937_basic_test() {
 fn gen_randoms(seed_data []u32, bound int) []u64 {
 	bound_u64 := u64(bound)
 	mut randoms := []u64{len: (20)}
-	mut rnd := mt19937.MT19937RNG{}
+	x := mt19937.MT19937RNG{}
+	mut rnd := rand.PRNG(x)
 	rnd.seed(seed_data)
 	for i in 0 .. 20 {
-		randoms[i] = rnd.u64n(bound_u64)
+		randoms[i] = rnd.u64n(bound_u64) or { panic("Couldn't obtain random u64") }
 	}
 	return randoms
 }
@@ -46,40 +48,29 @@ fn test_mt19937_reproducibility() {
 	}
 }
 
-// TODO: use the `in` syntax and remove this function
-// after generics has been completely implemented
-fn found(value u64, arr []u64) bool {
-	for item in arr {
-		if value == item {
-			return true
-		}
-	}
-	return false
-}
-
 fn test_mt19937_variability() {
 	// If this test fails and if it is certainly not the implementation
 	// at fault, try changing the seed values. Repeated values are
 	// improbable but not impossible.
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		mut values := []u64{cap: value_count}
 		for i in 0 .. value_count {
 			value := rng.u64()
-			assert !found(value, values)
+			assert value !in values
 			assert values.len == i
 			values << value
 		}
 	}
 }
 
-fn check_uniformity_u64(mut rng mt19937.MT19937RNG, range u64) {
+fn check_uniformity_u64(mut rng rand.PRNG, range u64) {
 	range_f64 := f64(range)
 	expected_mean := range_f64 / 2.0
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
-		diff := f64(rng.u64n(range)) - expected_mean
+		diff := f64(rng.u64n(range) or { panic("Couldn't obtain random u64") }) - expected_mean
 		variance += diff * diff
 	}
 	variance /= sample_size - 1
@@ -92,7 +83,7 @@ fn check_uniformity_u64(mut rng mt19937.MT19937RNG, range u64) {
 fn test_mt19937_uniformity_u64() {
 	ranges := [14019545, 80240, 130]
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for range in ranges {
 			check_uniformity_u64(mut rng, u64(range))
@@ -100,7 +91,7 @@ fn test_mt19937_uniformity_u64() {
 	}
 }
 
-fn check_uniformity_f64(mut rng mt19937.MT19937RNG) {
+fn check_uniformity_f64(mut rng rand.PRNG) {
 	expected_mean := 0.5
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
@@ -117,7 +108,7 @@ fn check_uniformity_f64(mut rng mt19937.MT19937RNG) {
 fn test_mt19937_uniformity_f64() {
 	// The f64 version
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		check_uniformity_f64(mut rng)
 	}
@@ -126,10 +117,10 @@ fn test_mt19937_uniformity_f64() {
 fn test_mt19937_u32n() {
 	max := u32(16384)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32n(max)
+			value := rng.u32n(max) or { panic("Couldn't obtain random u32") }
 			assert value >= 0
 			assert value < max
 		}
@@ -139,10 +130,10 @@ fn test_mt19937_u32n() {
 fn test_mt19937_u64n() {
 	max := u64(379091181005)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64n(max)
+			value := rng.u64n(max) or { panic("Couldn't obtain random u64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -153,10 +144,10 @@ fn test_mt19937_u32_in_range() {
 	max := u32(484468466)
 	min := u32(316846)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32_in_range(min, max)
+			value := rng.u32_in_range(min, max) or { panic("Couldn't obtain random u32 in range.") }
 			assert value >= min
 			assert value < max
 		}
@@ -167,10 +158,10 @@ fn test_mt19937_u64_in_range() {
 	max := u64(216468454685163)
 	min := u64(6848646868)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64_in_range(min, max)
+			value := rng.u64_in_range(min, max) or { panic("Couldn't obtain random u64 in range.") }
 			assert value >= min
 			assert value < max
 		}
@@ -181,7 +172,7 @@ fn test_mt19937_int31() {
 	max_u31 := int(0x7FFFFFFF)
 	sign_mask := int(0x80000000)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int31()
@@ -197,7 +188,7 @@ fn test_mt19937_int63() {
 	max_u63 := i64(0x7FFFFFFFFFFFFFFF)
 	sign_mask := i64(0x8000000000000000)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int63()
@@ -211,10 +202,10 @@ fn test_mt19937_int63() {
 fn test_mt19937_intn() {
 	max := 2525642
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.intn(max)
+			value := rng.intn(max) or { panic("Couldn't obtain random int") }
 			assert value >= 0
 			assert value < max
 		}
@@ -224,10 +215,10 @@ fn test_mt19937_intn() {
 fn test_mt19937_i64n() {
 	max := i64(3246727724653636)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64n(max)
+			value := rng.i64n(max) or { panic("Couldn't obtain random i64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -238,10 +229,10 @@ fn test_mt19937_int_in_range() {
 	min := -4252
 	max := 1034
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.int_in_range(min, max)
+			value := rng.int_in_range(min, max) or { panic("Couldn't obtain random int in range.") }
 			assert value >= min
 			assert value < max
 		}
@@ -252,10 +243,10 @@ fn test_mt19937_i64_in_range() {
 	min := i64(-24095)
 	max := i64(324058)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64_in_range(min, max)
+			value := rng.i64_in_range(min, max) or { panic("Couldn't obtain random i64 in range.") }
 			assert value >= min
 			assert value < max
 		}
@@ -264,7 +255,7 @@ fn test_mt19937_i64_in_range() {
 
 fn test_mt19937_f32() {
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f32()
@@ -276,7 +267,7 @@ fn test_mt19937_f32() {
 
 fn test_mt19937_f64() {
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f64()
@@ -289,10 +280,10 @@ fn test_mt19937_f64() {
 fn test_mt19937_f32n() {
 	max := f32(357.0)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32n(max)
+			value := rng.f32n(max) or { panic("Couldn't obtain random f32") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -302,10 +293,10 @@ fn test_mt19937_f32n() {
 fn test_mt19937_f64n() {
 	max := 1.52e6
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64n(max)
+			value := rng.f64n(max) or { panic("Couldn't obtain random f64") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -316,10 +307,10 @@ fn test_mt19937_f32_in_range() {
 	min := f32(-24.0)
 	max := f32(125.0)
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32_in_range(min, max)
+			value := rng.f32_in_range(min, max) or { panic("Couldn't obtain random f32 in range.") }
 			assert value >= min
 			assert value < max
 		}
@@ -330,10 +321,10 @@ fn test_mt19937_f64_in_range() {
 	min := -548.7
 	max := 5015.2
 	for seed in seeds {
-		mut rng := mt19937.MT19937RNG{}
+		mut rng := &rand.PRNG(&mt19937.MT19937RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64_in_range(min, max)
+			value := rng.f64_in_range(min, max) or { panic("Couldn't obtain random f64 in range.") }
 			assert value >= min
 			assert value < max
 		}

vlib/rand/musl/musl_rng.v

@@ -3,9 +3,7 @@
 // that can be found in the LICENSE file.
 module musl
 
-import math.bits
 import rand.seed
-import rand.constants
 
 // MuslRNG ported from https://git.musl-libc.org/cgit/musl/tree/src/prng/rand_r.c
 pub struct MuslRNG {
@@ -49,197 +47,6 @@ pub fn (mut rng MuslRNG) u64() u64 {
 	return u64(rng.u32()) | (u64(rng.u32()) << 32)
 }
 
-// u32n returns a pseudorandom 32-bit unsigned integer `u32` in range `[0, max)`.
-[inline]
-pub fn (mut rng MuslRNG) u32n(max u32) u32 {
-	if max == 0 {
-		eprintln('max must be positive integer.')
-		exit(1)
-	}
-	// Check SysRNG in system_rng.c.v for explanation
-	bit_len := bits.len_32(max)
-	if bit_len == 32 {
-		for {
-			value := rng.u32()
-			if value < max {
-				return value
-			}
-		}
-	} else {
-		mask := (u32(1) << (bit_len + 1)) - 1
-		for {
-			value := rng.u32() & mask
-			if value < max {
-				return value
-			}
-		}
-	}
-	return u32(0)
-}
-
-// u64n returns a pseudorandom 64-bit unsigned integer (`u64`) in range `[0, max)`.
-[inline]
-pub fn (mut rng MuslRNG) u64n(max u64) u64 {
-	if max == 0 {
-		eprintln('max must be positive integer.')
-		exit(1)
-	}
-	bit_len := bits.len_64(max)
-	if bit_len == 64 {
-		for {
-			value := rng.u64()
-			if value < max {
-				return value
-			}
-		}
-	} else {
-		mask := (u64(1) << (bit_len + 1)) - 1
-		for {
-			value := rng.u64() & mask
-			if value < max {
-				return value
-			}
-		}
-	}
-	return u64(0)
-}
-
-// u32_in_range returns a pseudorandom 32-bit unsigned integer (`u32`) in range `[min, max)`.
-[inline]
-pub fn (mut rng MuslRNG) u32_in_range(min u32, max u32) u32 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.u32n(u32(max - min))
-}
-
-// u64_in_range returns a pseudorandom 64-bit unsigned integer (`u64`) in range `[min, max)`.
-[inline]
-pub fn (mut rng MuslRNG) u64_in_range(min u64, max u64) u64 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.u64n(max - min)
-}
-
-// int returns a 32-bit signed (possibly negative) integer (`int`).
-[inline]
-pub fn (mut rng MuslRNG) int() int {
-	return int(rng.u32())
-}
-
-// i64 returns a 64-bit signed (possibly negative) integer (`i64`).
-[inline]
-pub fn (mut rng MuslRNG) i64() i64 {
-	return i64(rng.u64())
-}
-
-// int31 returns a 31-bit positive pseudorandom integer (`int`).
-[inline]
-pub fn (mut rng MuslRNG) int31() int {
-	return int(rng.u32() >> 1)
-}
-
-// int63 returns a 63-bit positive pseudorandom integer (`i64`).
-[inline]
-pub fn (mut rng MuslRNG) int63() i64 {
-	return i64(rng.u64() >> 1)
-}
-
-// intn returns a 32-bit positive int in range `[0, max)`.
-[inline]
-pub fn (mut rng MuslRNG) intn(max int) int {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return int(rng.u32n(u32(max)))
-}
-
-// i64n returns a 64-bit positive integer `i64` in range `[0, max)`.
-[inline]
-pub fn (mut rng MuslRNG) i64n(max i64) i64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return i64(rng.u64n(u64(max)))
-}
-
-// int_in_range returns a 32-bit positive integer `int` in range `[0, max)`.
-[inline]
-pub fn (mut rng MuslRNG) int_in_range(min int, max int) int {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.intn(max - min)
-}
-
-// i64_in_range returns a 64-bit positive integer `i64` in range `[0, max)`.
-[inline]
-pub fn (mut rng MuslRNG) i64_in_range(min i64, max i64) i64 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.i64n(max - min)
-}
-
-// f32 returns a pseudorandom `f32` value in range `[0, 1)`.
-[inline]
-pub fn (mut rng MuslRNG) f32() f32 {
-	return f32(rng.u32()) / constants.max_u32_as_f32
-}
-
-// f64 returns a pseudorandom `f64` value in range `[0, 1)`.
-[inline]
-pub fn (mut rng MuslRNG) f64() f64 {
-	return f64(rng.u64()) / constants.max_u64_as_f64
-}
-
-// f32n returns a pseudorandom `f32` value in range `[0, max)`.
-[inline]
-pub fn (mut rng MuslRNG) f32n(max f32) f32 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f32() * max
-}
-
-// f64n returns a pseudorandom `f64` value in range `[0, max)`.
-[inline]
-pub fn (mut rng MuslRNG) f64n(max f64) f64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f64() * max
-}
-
-// f32_in_range returns a pseudorandom `f32` in range `[min, max)`.
-[inline]
-pub fn (mut rng MuslRNG) f32_in_range(min f32, max f32) f32 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.f32n(max - min)
-}
-
-// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
-[inline]
-pub fn (mut rng MuslRNG) f64_in_range(min f64, max f64) f64 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.f64n(max - min)
-}
-
 // free should be called when the generator is no longer needed
 [unsafe]
 pub fn (mut rng MuslRNG) free() {

vlib/rand/musl/musl_rng_test.v

@@ -1,4 +1,5 @@
 import math
+import rand
 import rand.musl
 import rand.seed
 
@@ -17,10 +18,10 @@ const (
 fn gen_randoms(seed_data []u32, bound int) []u64 {
 	bound_u64 := u64(bound)
 	mut randoms := []u64{len: (20)}
-	mut rnd := musl.MuslRNG{}
+	mut rnd := &rand.PRNG(&musl.MuslRNG{})
 	rnd.seed(seed_data)
 	for i in 0 .. 20 {
-		randoms[i] = rnd.u64n(bound_u64)
+		randoms[i] = rnd.u64n(bound_u64) or { panic("Couldn't obtain u64") }
 	}
 	return randoms
 }
@@ -36,40 +37,29 @@ fn test_musl_reproducibility() {
 	}
 }
 
-// TODO: use the `in` syntax and remove this function
-// after generics has been completely implemented
-fn found(value u64, arr []u64) bool {
-	for item in arr {
-		if value == item {
-			return true
-		}
-	}
-	return false
-}
-
 fn test_musl_variability() {
 	// If this test fails and if it is certainly not the implementation
 	// at fault, try changing the seed values. Repeated values are
 	// improbable but not impossible.
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		mut values := []u64{cap: value_count}
 		for i in 0 .. value_count {
 			value := rng.u64()
-			assert !found(value, values)
+			assert value !in values
 			assert values.len == i
 			values << value
 		}
 	}
 }
 
-fn check_uniformity_u64(mut rng musl.MuslRNG, range u64) {
+fn check_uniformity_u64(mut rng rand.PRNG, range u64) {
 	range_f64 := f64(range)
 	expected_mean := range_f64 / 2.0
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
-		diff := f64(rng.u64n(range)) - expected_mean
+		diff := f64(rng.u64n(range) or { panic("Couldn't obtain u64") }) - expected_mean
 		variance += diff * diff
 	}
 	variance /= sample_size - 1
@@ -82,7 +72,7 @@ fn check_uniformity_u64(mut rng musl.MuslRNG, range u64) {
 fn test_musl_uniformity_u64() {
 	ranges := [14019545, 80240, 130]
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for range in ranges {
 			check_uniformity_u64(mut rng, u64(range))
@@ -90,7 +80,7 @@ fn test_musl_uniformity_u64() {
 	}
 }
 
-fn check_uniformity_f64(mut rng musl.MuslRNG) {
+fn check_uniformity_f64(mut rng rand.PRNG) {
 	expected_mean := 0.5
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
@@ -107,7 +97,7 @@ fn check_uniformity_f64(mut rng musl.MuslRNG) {
 fn test_musl_uniformity_f64() {
 	// The f64 version
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		check_uniformity_f64(mut rng)
 	}
@@ -116,10 +106,10 @@ fn test_musl_uniformity_f64() {
 fn test_musl_u32n() {
 	max := u32(16384)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32n(max)
+			value := rng.u32n(max) or { panic("Couldn't obtain u32") }
 			assert value >= 0
 			assert value < max
 		}
@@ -129,10 +119,10 @@ fn test_musl_u32n() {
 fn test_musl_u64n() {
 	max := u64(379091181005)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64n(max)
+			value := rng.u64n(max) or { panic("Couldn't obtain u64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -143,10 +133,10 @@ fn test_musl_u32_in_range() {
 	max := u32(484468466)
 	min := u32(316846)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32_in_range(min, max)
+			value := rng.u32_in_range(min, max) or { panic("Couldn't obtain u32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -157,10 +147,10 @@ fn test_musl_u64_in_range() {
 	max := u64(216468454685163)
 	min := u64(6848646868)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64_in_range(min, max)
+			value := rng.u64_in_range(min, max) or { panic("Couldn't obtain u64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -171,7 +161,7 @@ fn test_musl_int31() {
 	max_u31 := int(0x7FFFFFFF)
 	sign_mask := int(0x80000000)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int31()
@@ -187,7 +177,7 @@ fn test_musl_int63() {
 	max_u63 := i64(0x7FFFFFFFFFFFFFFF)
 	sign_mask := i64(0x8000000000000000)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int63()
@@ -201,10 +191,10 @@ fn test_musl_int63() {
 fn test_musl_intn() {
 	max := 2525642
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.intn(max)
+			value := rng.intn(max) or { panic("Couldn't obtain int") }
 			assert value >= 0
 			assert value < max
 		}
@@ -214,10 +204,10 @@ fn test_musl_intn() {
 fn test_musl_i64n() {
 	max := i64(3246727724653636)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64n(max)
+			value := rng.i64n(max) or { panic("Couldn't obtain i64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -228,10 +218,10 @@ fn test_musl_int_in_range() {
 	min := -4252
 	max := 1034
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.int_in_range(min, max)
+			value := rng.int_in_range(min, max) or { panic("Couldn't obtain int in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -242,10 +232,10 @@ fn test_musl_i64_in_range() {
 	min := i64(-24095)
 	max := i64(324058)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64_in_range(min, max)
+			value := rng.i64_in_range(min, max) or { panic("Couldn't obtain i64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -254,7 +244,7 @@ fn test_musl_i64_in_range() {
 
 fn test_musl_f32() {
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f32()
@@ -266,7 +256,7 @@ fn test_musl_f32() {
 
 fn test_musl_f64() {
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f64()
@@ -279,10 +269,10 @@ fn test_musl_f64() {
 fn test_musl_f32n() {
 	max := f32(357.0)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32n(max)
+			value := rng.f32n(max) or { panic("Couldn't obtain f32") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -292,10 +282,10 @@ fn test_musl_f32n() {
 fn test_musl_f64n() {
 	max := 1.52e6
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64n(max)
+			value := rng.f64n(max) or { panic("Couldn't obtain f64") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -306,10 +296,10 @@ fn test_musl_f32_in_range() {
 	min := f32(-24.0)
 	max := f32(125.0)
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32_in_range(min, max)
+			value := rng.f32_in_range(min, max) or { panic("Couldn't obtain f32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -320,10 +310,10 @@ fn test_musl_f64_in_range() {
 	min := -548.7
 	max := 5015.2
 	for seed in seeds {
-		mut rng := musl.MuslRNG{}
+		mut rng := &rand.PRNG(&musl.MuslRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64_in_range(min, max)
+			value := rng.f64_in_range(min, max) or { panic("Couldn't obtain f64 in range") }
 			assert value >= min
 			assert value < max
 		}

vlib/rand/pcg32/pcg32.v

@@ -48,183 +48,6 @@ pub fn (mut rng PCG32RNG) u64() u64 {
 	return u64(rng.u32()) | (u64(rng.u32()) << 32)
 }
 
-// u32n returns a pseudorandom 32-bit unsigned `u32` in range `[0, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) u32n(max u32) u32 {
-	if max == 0 {
-		eprintln('max must be positive')
-		exit(1)
-	}
-	// To avoid bias, we need to make the range of the RNG a multiple of
-	// max, which we do by dropping output less than a threshold.
-	threshold := (-max % max)
-	// Uniformity guarantees that loop below will terminate. In practice, it
-	// should usually terminate quickly; on average (assuming all max's are
-	// equally likely), 82.25% of the time, we can expect it to require just
-	// one iteration. In practice, max's are typically small and only a
-	// tiny amount of the range is eliminated.
-	for {
-		r := rng.u32()
-		if r >= threshold {
-			return r % max
-		}
-	}
-	return u32(0)
-}
-
-// u64n returns a pseudorandom 64-bit unsigned `u64` in range `[0, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) u64n(max u64) u64 {
-	if max == 0 {
-		eprintln('max must be positive')
-		exit(1)
-	}
-	threshold := (-max % max)
-	for {
-		r := rng.u64()
-		if r >= threshold {
-			return r % max
-		}
-	}
-	return u64(0)
-}
-
-// u32_in_range returns a pseudorandom 32-bit unsigned `u32` in range `[min, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) u32_in_range(min u32, max u32) u32 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.u32n(u32(max - min))
-}
-
-// u64_in_range returns a pseudorandom 64-bit unsigned `u64` in range `[min, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) u64_in_range(min u64, max u64) u64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.u64n(max - min)
-}
-
-// int returns a 32-bit signed (possibly negative) `int`.
-[inline]
-pub fn (mut rng PCG32RNG) int() int {
-	return int(rng.u32())
-}
-
-// i64 returns a 64-bit signed (possibly negative) `i64`.
-[inline]
-pub fn (mut rng PCG32RNG) i64() i64 {
-	return i64(rng.u64())
-}
-
-// int31 returns a 31-bit positive pseudorandom `int`.
-[inline]
-pub fn (mut rng PCG32RNG) int31() int {
-	return int(rng.u32() >> 1)
-}
-
-// int63 returns a 63-bit positive pseudorandom `i64`.
-[inline]
-pub fn (mut rng PCG32RNG) int63() i64 {
-	return i64(rng.u64() >> 1)
-}
-
-// intn returns a 32-bit positive `int` in range `[0, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) intn(max int) int {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return int(rng.u32n(u32(max)))
-}
-
-// i64n returns a 64-bit positive `i64` in range `[0, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) i64n(max i64) i64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return i64(rng.u64n(u64(max)))
-}
-
-// int_in_range returns a 32-bit positive `int` in range `[0, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) int_in_range(min int, max int) int {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.intn(max - min)
-}
-
-// i64_in_range returns a 64-bit positive `i64` in range `[0, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) i64_in_range(min i64, max i64) i64 {
-	if max <= min {
-		eprintln('max must be greater than min.')
-		exit(1)
-	}
-	return min + rng.i64n(max - min)
-}
-
-// f32 returns a pseudorandom `f32` value in range `[0, 1)`.
-[inline]
-pub fn (mut rng PCG32RNG) f32() f32 {
-	return f32(rng.u32()) / constants.max_u32_as_f32
-}
-
-// f64 returns a pseudorandom `f64` value in range `[0, 1)`.
-[inline]
-pub fn (mut rng PCG32RNG) f64() f64 {
-	return f64(rng.u64()) / constants.max_u64_as_f64
-}
-
-// f32n returns a pseudorandom `f32` value in range `[0, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) f32n(max f32) f32 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f32() * max
-}
-
-// f64n returns a pseudorandom `f64` value in range `[0, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) f64n(max f64) f64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f64() * max
-}
-
-// f32_in_range returns a pseudorandom `f32` in range `[min, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) f32_in_range(min f32, max f32) f32 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.f32n(max - min)
-}
-
-// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
-[inline]
-pub fn (mut rng PCG32RNG) f64_in_range(min f64, max f64) f64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.f64n(max - min)
-}
-
 // free should be called when the generator is no longer needed
 [unsafe]
 pub fn (mut rng PCG32RNG) free() {

vlib/rand/pcg32/pcg32_test.v

@@ -17,10 +17,10 @@ const (
 
 fn gen_randoms(seed_data []u32, bound int) []u32 {
 	mut randoms := []u32{len: 20}
-	mut rng := pcg32.PCG32RNG{}
+	mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 	rng.seed(seed_data)
 	for i in 0 .. 20 {
-		randoms[i] = rng.u32n(u32(bound))
+		randoms[i] = rng.u32n(u32(bound)) or { panic("Couldn't obtain u32") }
 	}
 	return randoms
 }
@@ -38,40 +38,29 @@ fn test_pcg32_reproducibility() {
 	}
 }
 
-// TODO: use the `in` syntax and remove this function
-// after generics has been completely implemented
-fn found(value u64, arr []u64) bool {
-	for item in arr {
-		if value == item {
-			return true
-		}
-	}
-	return false
-}
-
 fn test_pcg32_variability() {
 	// If this test fails and if it is certainly not the implementation
 	// at fault, try changing the seed values. Repeated values are
 	// improbable but not impossible.
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		mut values := []u64{cap: value_count}
 		for i in 0 .. value_count {
 			value := rng.u64()
-			assert !found(value, values)
+			assert value !in values
 			assert values.len == i
 			values << value
 		}
 	}
 }
 
-fn check_uniformity_u64(mut rng pcg32.PCG32RNG, range u64) {
+fn check_uniformity_u64(mut rng rand.PRNG, range u64) {
 	range_f64 := f64(range)
 	expected_mean := range_f64 / 2.0
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
-		diff := f64(rng.u64n(range)) - expected_mean
+		diff := f64(rng.u64n(range) or { panic("Couldn't obtain u64") }) - expected_mean
 		variance += diff * diff
 	}
 	variance /= sample_size - 1
@@ -84,7 +73,7 @@ fn check_uniformity_u64(mut rng pcg32.PCG32RNG, range u64) {
 fn test_pcg32_uniformity_u64() {
 	ranges := [14019545, 80240, 130]
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for range in ranges {
 			check_uniformity_u64(mut rng, u64(range))
@@ -92,7 +81,7 @@ fn test_pcg32_uniformity_u64() {
 	}
 }
 
-fn check_uniformity_f64(mut rng pcg32.PCG32RNG) {
+fn check_uniformity_f64(mut rng rand.PRNG) {
 	expected_mean := 0.5
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
@@ -109,7 +98,7 @@ fn check_uniformity_f64(mut rng pcg32.PCG32RNG) {
 fn test_pcg32_uniformity_f64() {
 	// The f64 version
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		check_uniformity_f64(mut rng)
 	}
@@ -118,10 +107,10 @@ fn test_pcg32_uniformity_f64() {
 fn test_pcg32_u32n() {
 	max := u32(16384)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32n(max)
+			value := rng.u32n(max) or { panic("Couldn't obtain u32") }
 			assert value >= 0
 			assert value < max
 		}
@@ -131,10 +120,10 @@ fn test_pcg32_u32n() {
 fn test_pcg32_u64n() {
 	max := u64(379091181005)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64n(max)
+			value := rng.u64n(max) or { panic("Couldn't obtain u64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -145,10 +134,12 @@ fn test_pcg32_u32_in_range() {
 	max := u32(484468466)
 	min := u32(316846)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32_in_range(u32(min), u32(max))
+			value := rng.u32_in_range(u32(min), u32(max)) or {
+				panic("Couldn't obtain u32 in range")
+			}
 			assert value >= min
 			assert value < max
 		}
@@ -159,10 +150,10 @@ fn test_pcg32_u64_in_range() {
 	max := u64(216468454685163)
 	min := u64(6848646868)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64_in_range(min, max)
+			value := rng.u64_in_range(min, max) or { panic("Couldn't obtain u64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -173,7 +164,7 @@ fn test_pcg32_int31() {
 	max_u31 := int(0x7FFFFFFF)
 	sign_mask := int(0x80000000)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int31()
@@ -189,7 +180,7 @@ fn test_pcg32_int63() {
 	max_u63 := i64(0x7FFFFFFFFFFFFFFF)
 	sign_mask := i64(0x8000000000000000)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int63()
@@ -203,10 +194,10 @@ fn test_pcg32_int63() {
 fn test_pcg32_intn() {
 	max := 2525642
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.intn(max)
+			value := rng.intn(max) or { panic("Couldn't obtain int") }
 			assert value >= 0
 			assert value < max
 		}
@@ -216,10 +207,10 @@ fn test_pcg32_intn() {
 fn test_pcg32_i64n() {
 	max := i64(3246727724653636)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64n(max)
+			value := rng.i64n(max) or { panic("Couldn't obtain i64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -230,10 +221,10 @@ fn test_pcg32_int_in_range() {
 	min := -4252
 	max := 1034
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.int_in_range(min, max)
+			value := rng.int_in_range(min, max) or { panic("Couldn't obtain int in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -244,10 +235,10 @@ fn test_pcg32_i64_in_range() {
 	min := i64(-24095)
 	max := i64(324058)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64_in_range(min, max)
+			value := rng.i64_in_range(min, max) or { panic("Couldn't obtain i64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -256,7 +247,7 @@ fn test_pcg32_i64_in_range() {
 
 fn test_pcg32_f32() {
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f32()
@@ -268,7 +259,7 @@ fn test_pcg32_f32() {
 
 fn test_pcg32_f64() {
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f64()
@@ -281,10 +272,10 @@ fn test_pcg32_f64() {
 fn test_pcg32_f32n() {
 	max := f32(357.0)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32n(max)
+			value := rng.f32n(max) or { panic("Couldn't obtain f32") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -294,10 +285,10 @@ fn test_pcg32_f32n() {
 fn test_pcg32_f64n() {
 	max := 1.52e6
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64n(max)
+			value := rng.f64n(max) or { panic("Couldn't obtain f64") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -308,10 +299,10 @@ fn test_pcg32_f32_in_range() {
 	min := f32(-24.0)
 	max := f32(125.0)
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32_in_range(min, max)
+			value := rng.f32_in_range(min, max) or { panic("Couldn't obtain f32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -322,10 +313,10 @@ fn test_pcg32_f64_in_range() {
 	min := -548.7
 	max := 5015.2
 	for seed in seeds {
-		mut rng := pcg32.PCG32RNG{}
+		mut rng := &rand.PRNG(&pcg32.PCG32RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64_in_range(min, max)
+			value := rng.f64_in_range(min, max) or { panic("Couldn't obtain f64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -333,5 +324,5 @@ fn test_pcg32_f64_in_range() {
 }
 
 fn test_change_default_random_generator() {
-	rand.set_rng(pcg32.PCG32RNG{})
+	rand.set_rng(&rand.PRNG(&pcg32.PCG32RNG{}))
 }

vlib/rand/rand.c.v

@@ -110,7 +110,7 @@ pub fn string_from_set(charset string, len int) string {
 	mut buf := unsafe { malloc_noscan(len + 1) }
 	for i in 0 .. len {
 		unsafe {
-			buf[i] = charset[intn(charset.len)]
+			buf[i] = charset[intn(charset.len) or { 0 }]
 		}
 	}
 	unsafe {

vlib/rand/rand.v

@@ -4,7 +4,9 @@
 [has_globals]
 module rand
 
+import math.bits
 import rand.config
+import rand.constants
 import rand.wyrand
 
 // PRNG is a common interface for all PRNGs that can be used seamlessly with the rand
@@ -13,29 +15,240 @@ import rand.wyrand
 pub interface PRNG {
 mut:
 	seed(seed_data []u32)
+	// TODO: Support buffering for bytes
+	// byte() byte
+	// bytes(bytes_needed int) ?[]byte
+	// u16() u16
 	u32() u32
 	u64() u64
-	u32n(max u32) u32
-	u64n(max u64) u64
-	u32_in_range(min u32, max u32) u32
-	u64_in_range(min u64, max u64) u64
-	int() int
-	i64() i64
-	int31() int
-	int63() i64
-	intn(max int) int
-	i64n(max i64) i64
-	int_in_range(min int, max int) int
-	i64_in_range(min i64, max i64) i64
-	f32() f32
-	f64() f64
-	f32n(max f32) f32
-	f64n(max f64) f64
-	f32_in_range(min f32, max f32) f32
-	f64_in_range(min f64, max f64) f64
 	free()
 }
 
+// byte returns a uniformly distributed pseudorandom 8-bit unsigned positive `byte`.
+[inline]
+pub fn (mut rng PRNG) byte() byte {
+	// TODO: Reimplement for all PRNGs efficiently
+	return byte(rng.u32() & 0xff)
+}
+
+// bytes returns a buffer of `bytes_needed` random bytes.
+[inline]
+pub fn (mut rng PRNG) bytes(bytes_needed int) ?[]byte {
+	// TODO: Reimplement for all PRNGs efficiently
+	if bytes_needed < 0 {
+		return error('can not read < 0 random bytes')
+	}
+	mut res := []byte{cap: bytes_needed}
+	mut remaining := bytes_needed
+
+	for remaining > 8 {
+		mut value := rng.u64()
+		for _ in 0 .. 8 {
+			res << byte(value & 0xff)
+			value >>= 8
+		}
+		remaining -= 8
+	}
+	for remaining > 4 {
+		mut value := rng.u32()
+		for _ in 0 .. 4 {
+			res << byte(value & 0xff)
+			value >>= 8
+		}
+		remaining -= 4
+	}
+	for remaining > 0 {
+		res << rng.byte()
+		remaining -= 1
+	}
+	return res
+}
+
+// u32n returns a uniformly distributed pseudorandom 32-bit signed positive `u32` in range `[0, max)`.
+[inline]
+pub fn (mut rng PRNG) u32n(max u32) ?u32 {
+	if max == 0 {
+		return error('max must be positive integer')
+	}
+	// Owing to the pigeon-hole principle, we can't simply do
+	// val := rng.u32() % max.
+	// It'll wreck the properties of the distribution unless
+	// max evenly divides 2^32. So we divide evenly to
+	// the closest power of two. Then we loop until we find
+	// an int in the required range
+	bit_len := bits.len_32(max)
+	if bit_len == 32 {
+		for {
+			value := rng.u32()
+			if value < max {
+				return value
+			}
+		}
+	} else {
+		mask := (u32(1) << (bit_len + 1)) - 1
+		for {
+			value := rng.u32() & mask
+			if value < max {
+				return value
+			}
+		}
+	}
+	return u32(0)
+}
+
+// u64n returns a uniformly distributed pseudorandom 64-bit signed positive `u64` in range `[0, max)`.
+[inline]
+pub fn (mut rng PRNG) u64n(max u64) ?u64 {
+	if max == 0 {
+		return error('max must be positive integer')
+	}
+	bit_len := bits.len_64(max)
+	if bit_len == 64 {
+		for {
+			value := rng.u64()
+			if value < max {
+				return value
+			}
+		}
+	} else {
+		mask := (u64(1) << (bit_len + 1)) - 1
+		for {
+			value := rng.u64() & mask
+			if value < max {
+				return value
+			}
+		}
+	}
+	return u64(0)
+}
+
+// u32_in_range returns a uniformly distributed pseudorandom 32-bit unsigned `u32` in range `[min, max)`.
+[inline]
+pub fn (mut rng PRNG) u32_in_range(min u32, max u32) ?u32 {
+	if max <= min {
+		return error('max must be greater than min')
+	}
+	return min + rng.u32n(max - min) ?
+}
+
+// u64_in_range returns a uniformly distributed pseudorandom 64-bit unsigned `u64` in range `[min, max)`.
+[inline]
+pub fn (mut rng PRNG) u64_in_range(min u64, max u64) ?u64 {
+	if max <= min {
+		return error('max must be greater than min')
+	}
+	return min + rng.u64n(max - min) ?
+}
+
+// int returns a (possibly negative) pseudorandom 32-bit `int`.
+[inline]
+pub fn (mut rng PRNG) int() int {
+	return int(rng.u32())
+}
+
+// i64 returns a (possibly negative) pseudorandom 64-bit `i64`.
+[inline]
+pub fn (mut rng PRNG) i64() i64 {
+	return i64(rng.u64())
+}
+
+// int31 returns a positive pseudorandom 31-bit `int`.
+[inline]
+pub fn (mut rng PRNG) int31() int {
+	return int(rng.u32() & constants.u31_mask) // Set the 32nd bit to 0.
+}
+
+// int63 returns a positive pseudorandom 63-bit `i64`.
+[inline]
+pub fn (mut rng PRNG) int63() i64 {
+	return i64(rng.u64() & constants.u63_mask) // Set the 64th bit to 0.
+}
+
+// intn returns a pseudorandom `int` in range `[0, max)`.
+[inline]
+pub fn (mut rng PRNG) intn(max int) ?int {
+	if max <= 0 {
+		return error('max has to be positive.')
+	}
+	return int(rng.u32n(u32(max)) ?)
+}
+
+// i64n returns a pseudorandom int that lies in `[0, max)`.
+[inline]
+pub fn (mut rng PRNG) i64n(max i64) ?i64 {
+	if max <= 0 {
+		return error('max has to be positive.')
+	}
+	return i64(rng.u64n(u64(max)) ?)
+}
+
+// int_in_range returns a pseudorandom `int` in range `[min, max)`.
+[inline]
+pub fn (mut rng PRNG) int_in_range(min int, max int) ?int {
+	if max <= min {
+		return error('max must be greater than min')
+	}
+	// This supports negative ranges like [-10, -5) because the difference is positive
+	return min + rng.intn(max - min) ?
+}
+
+// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
+[inline]
+pub fn (mut rng PRNG) i64_in_range(min i64, max i64) ?i64 {
+	if max <= min {
+		return error('max must be greater than min')
+	}
+	return min + rng.i64n(max - min) ?
+}
+
+// f32 returns a pseudorandom `f32` value in range `[0, 1)`.
+[inline]
+pub fn (mut rng PRNG) f32() f32 {
+	return f32(rng.u32()) / constants.max_u32_as_f32
+}
+
+// f64 returns a pseudorandom `f64` value in range `[0, 1)`.
+[inline]
+pub fn (mut rng PRNG) f64() f64 {
+	return f64(rng.u64()) / constants.max_u64_as_f64
+}
+
+// f32n returns a pseudorandom `f32` value in range `[0, max)`.
+[inline]
+pub fn (mut rng PRNG) f32n(max f32) ?f32 {
+	if max <= 0 {
+		return error('max has to be positive.')
+	}
+	return rng.f32() * max
+}
+
+// f64n returns a pseudorandom `f64` value in range `[0, max)`.
+[inline]
+pub fn (mut rng PRNG) f64n(max f64) ?f64 {
+	if max <= 0 {
+		return error('max has to be positive.')
+	}
+	return rng.f64() * max
+}
+
+// f32_in_range returns a pseudorandom `f32` in range `[min, max)`.
+[inline]
+pub fn (mut rng PRNG) f32_in_range(min f32, max f32) ?f32 {
+	if max <= min {
+		return error('max must be greater than min')
+	}
+	return min + rng.f32n(max - min) ?
+}
+
+// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
+[inline]
+pub fn (mut rng PRNG) f64_in_range(min f64, max f64) ?f64 {
+	if max <= min {
+		return error('max must be greater than min')
+	}
+	return min + rng.f64n(max - min) ?
+}
+
 __global default_rng &PRNG
 
 // new_default returns a new instance of the default RNG. If the seed is not provided, the current time will be used to seed the instance.
@@ -79,22 +292,22 @@ pub fn u64() u64 {
 }
 
 // u32n returns a uniformly distributed pseudorandom 32-bit signed positive `u32` in range `[0, max)`.
-pub fn u32n(max u32) u32 {
+pub fn u32n(max u32) ?u32 {
 	return default_rng.u32n(max)
 }
 
 // u64n returns a uniformly distributed pseudorandom 64-bit signed positive `u64` in range `[0, max)`.
-pub fn u64n(max u64) u64 {
+pub fn u64n(max u64) ?u64 {
 	return default_rng.u64n(max)
 }
 
 // u32_in_range returns a uniformly distributed pseudorandom 32-bit unsigned `u32` in range `[min, max)`.
-pub fn u32_in_range(min u32, max u32) u32 {
+pub fn u32_in_range(min u32, max u32) ?u32 {
 	return default_rng.u32_in_range(min, max)
 }
 
 // u64_in_range returns a uniformly distributed pseudorandom 64-bit unsigned `u64` in range `[min, max)`.
-pub fn u64_in_range(min u64, max u64) u64 {
+pub fn u64_in_range(min u64, max u64) ?u64 {
 	return default_rng.u64_in_range(min, max)
 }
 
@@ -104,18 +317,18 @@ pub fn int() int {
 }
 
 // intn returns a uniformly distributed pseudorandom 32-bit signed positive `int` in range `[0, max)`.
-pub fn intn(max int) int {
+pub fn intn(max int) ?int {
 	return default_rng.intn(max)
 }
 
 // byte returns a uniformly distributed pseudorandom 8-bit unsigned positive `byte`.
 pub fn byte() byte {
-	return byte(default_rng.u32() & 0xff)
+	return default_rng.byte()
 }
 
 // int_in_range returns a uniformly distributed pseudorandom  32-bit signed int in range `[min, max)`.
 // Both `min` and `max` can be negative, but we must have `min < max`.
-pub fn int_in_range(min int, max int) int {
+pub fn int_in_range(min int, max int) ?int {
 	return default_rng.int_in_range(min, max)
 }
 
@@ -130,12 +343,12 @@ pub fn i64() i64 {
 }
 
 // i64n returns a uniformly distributed pseudorandom 64-bit signed positive `i64` in range `[0, max)`.
-pub fn i64n(max i64) i64 {
+pub fn i64n(max i64) ?i64 {
 	return default_rng.i64n(max)
 }
 
 // i64_in_range returns a uniformly distributed pseudorandom 64-bit signed `i64` in range `[min, max)`.
-pub fn i64_in_range(min i64, max i64) i64 {
+pub fn i64_in_range(min i64, max i64) ?i64 {
 	return default_rng.i64_in_range(min, max)
 }
 
@@ -155,33 +368,28 @@ pub fn f64() f64 {
 }
 
 // f32n returns a uniformly distributed 32-bit floating point in range `[0, max)`.
-pub fn f32n(max f32) f32 {
+pub fn f32n(max f32) ?f32 {
 	return default_rng.f32n(max)
 }
 
 // f64n returns a uniformly distributed 64-bit floating point in range `[0, max)`.
-pub fn f64n(max f64) f64 {
+pub fn f64n(max f64) ?f64 {
 	return default_rng.f64n(max)
 }
 
 // f32_in_range returns a uniformly distributed 32-bit floating point in range `[min, max)`.
-pub fn f32_in_range(min f32, max f32) f32 {
+pub fn f32_in_range(min f32, max f32) ?f32 {
 	return default_rng.f32_in_range(min, max)
 }
 
 // f64_in_range returns a uniformly distributed 64-bit floating point in range `[min, max)`.
-pub fn f64_in_range(min f64, max f64) f64 {
+pub fn f64_in_range(min f64, max f64) ?f64 {
 	return default_rng.f64_in_range(min, max)
 }
 
 // bytes returns a buffer of `bytes_needed` random bytes
 pub fn bytes(bytes_needed int) ?[]byte {
-	if bytes_needed < 0 {
+	return default_rng.bytes(bytes_needed)
-		return error('can not read < 0 random bytes')
-	}
-	mut res := []byte{len: bytes_needed}
-	read(mut res)
-	return res
 }
 
 const (

vlib/rand/random_numbers_test.v

@@ -12,7 +12,7 @@ fn get_n_random_ints(seed_data []u32, n int) []int {
 	mut values := []int{cap: n}
 	rand.seed(seed_data)
 	for _ in 0 .. n {
-		values << rand.intn(n)
+		values << rand.intn(n) or { panic("Couldn't obtain int") }
 	}
 	return values
 }
@@ -29,7 +29,7 @@ fn test_rand_reproducibility() {
 fn test_rand_u32n() {
 	max := u32(16384)
 	for _ in 0 .. rnd_count {
-		value := rand.u32n(max)
+		value := rand.u32n(max) or { panic("Couldn't obtain u32") }
 		assert value >= 0
 		assert value < max
 	}
@@ -38,7 +38,7 @@ fn test_rand_u32n() {
 fn test_rand_u64n() {
 	max := u64(379091181005)
 	for _ in 0 .. rnd_count {
-		value := rand.u64n(max)
+		value := rand.u64n(max) or { panic("Couldn't obtain u64") }
 		assert value >= 0
 		assert value < max
 	}
@@ -48,7 +48,7 @@ fn test_rand_u32_in_range() {
 	max := u32(484468466)
 	min := u32(316846)
 	for _ in 0 .. rnd_count {
-		value := rand.u32_in_range(min, max)
+		value := rand.u32_in_range(min, max) or { panic("Couldn't obtain u32 in range") }
 		assert value >= min
 		assert value < max
 	}
@@ -58,7 +58,7 @@ fn test_rand_u64_in_range() {
 	max := u64(216468454685163)
 	min := u64(6848646868)
 	for _ in 0 .. rnd_count {
-		value := rand.u64_in_range(min, max)
+		value := rand.u64_in_range(min, max) or { panic("Couldn't obtain u64 in range") }
 		assert value >= min
 		assert value < max
 	}
@@ -67,7 +67,7 @@ fn test_rand_u64_in_range() {
 fn test_rand_intn() {
 	max := 2525642
 	for _ in 0 .. rnd_count {
-		value := rand.intn(max)
+		value := rand.intn(max) or { panic("Couldn't obtain int") }
 		assert value >= 0
 		assert value < max
 	}
@@ -76,7 +76,7 @@ fn test_rand_intn() {
 fn test_rand_i64n() {
 	max := i64(3246727724653636)
 	for _ in 0 .. rnd_count {
-		value := rand.i64n(max)
+		value := rand.i64n(max) or { panic("Couldn't obtain i64") }
 		assert value >= 0
 		assert value < max
 	}
@@ -86,7 +86,7 @@ fn test_rand_int_in_range() {
 	min := -4252
 	max := 23054962
 	for _ in 0 .. rnd_count {
-		value := rand.int_in_range(min, max)
+		value := rand.int_in_range(min, max) or { panic("Couldn't obtain int in range") }
 		assert value >= min
 		assert value < max
 	}
@@ -96,7 +96,7 @@ fn test_rand_i64_in_range() {
 	min := i64(-24095)
 	max := i64(324058)
 	for _ in 0 .. rnd_count {
-		value := rand.i64_in_range(min, max)
+		value := rand.i64_in_range(min, max) or { panic("Couldn't obtain i64 in range") }
 		assert value >= min
 		assert value < max
 	}
@@ -144,7 +144,7 @@ fn test_rand_f64() {
 fn test_rand_f32n() {
 	max := f32(357.0)
 	for _ in 0 .. rnd_count {
-		value := rand.f32n(max)
+		value := rand.f32n(max) or { panic("Couldn't obtain f32") }
 		assert value >= 0.0
 		assert value < max
 	}
@@ -153,7 +153,7 @@ fn test_rand_f32n() {
 fn test_rand_f64n() {
 	max := f64(1.52e6)
 	for _ in 0 .. rnd_count {
-		value := rand.f64n(max)
+		value := rand.f64n(max) or { panic("Couldn't obtain f64") }
 		assert value >= 0.0
 		assert value < max
 	}
@@ -163,7 +163,7 @@ fn test_rand_f32_in_range() {
 	min := f32(-24.0)
 	max := f32(125.0)
 	for _ in 0 .. rnd_count {
-		value := rand.f32_in_range(min, max)
+		value := rand.f32_in_range(min, max) or { panic("Couldn't obtain f32 in range") }
 		assert value >= min
 		assert value < max
 	}
@@ -173,7 +173,7 @@ fn test_rand_f64_in_range() {
 	min := f64(-548.7)
 	max := f64(5015.2)
 	for _ in 0 .. rnd_count {
-		value := rand.f64_in_range(min, max)
+		value := rand.f64_in_range(min, max) or { panic("Couldn't obtain f64 in range") }
 		assert value >= min
 		assert value < max
 	}
@@ -204,7 +204,7 @@ fn test_rand_string_from_set() {
 	]
 	for charset in sets {
 		for _ in 0 .. string_count {
-			len := rand.intn(rnd_count)
+			len := rand.intn(rnd_count) or { panic("Couldn't obtain int") }
 			str := rand.string_from_set(charset, len)
 			assert str.len == len
 			for character in str {
@@ -275,10 +275,10 @@ fn test_rand_ascii() {
 fn ensure_same_output(mut rng rand.PRNG) {
 	for _ in 0 .. 100 {
 		assert rand.int() == rng.int()
-		assert rand.intn(45) == rng.intn(45)
+		assert rand.intn(45) or { 0 } == rng.intn(45) or { 0 }
 		assert rand.u64() == rng.u64()
 		assert rand.f64() == rng.f64()
-		assert rand.u32n(25) == rng.u32n(25)
+		assert rand.u32n(25) or { 0 } == rng.u32n(25) or { 0 }
 	}
 }
 

vlib/rand/splitmix64/splitmix64.v

@@ -50,180 +50,6 @@ pub fn (mut rng SplitMix64RNG) u64() u64 {
 	return z ^ (z >> (31))
 }
 
-// u32n returns a pseudorandom `u32` less than `bound`.
-[inline]
-pub fn (mut rng SplitMix64RNG) u32n(bound u32) u32 {
-	// This function is kept similar to the u64 version
-	if bound == 0 {
-		eprintln('max must be non-zero')
-		exit(1)
-	}
-	threshold := -bound % bound
-	for {
-		r := rng.u32()
-		if r >= threshold {
-			return r % bound
-		}
-	}
-	return u32(0)
-}
-
-// u64n returns a pseudorandom `u64` less than `bound`.
-[inline]
-pub fn (mut rng SplitMix64RNG) u64n(bound u64) u64 {
-	// See pcg32.v for explanation of comment. This algorithm
-	// existed before the refactoring.
-	if bound == 0 {
-		eprintln('max must be non-zero')
-		exit(1)
-	}
-	threshold := -bound % bound
-	for {
-		r := rng.u64()
-		if r >= threshold {
-			return r % bound
-		}
-	}
-	return u64(0)
-}
-
-// u32n returns a pseudorandom `u32` value that is guaranteed to be in range `[min, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) u32_in_range(min u32, max u32) u32 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.u32n(max - min)
-}
-
-// u64n returns a pseudorandom `u64` value that is guaranteed to be in range `[min, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) u64_in_range(min u64, max u64) u64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.u64n(max - min)
-}
-
-// int returns a pseudorandom 32-bit (possibly negative) `int`.
-[inline]
-pub fn (mut rng SplitMix64RNG) int() int {
-	return int(rng.u32())
-}
-
-// i64 returns a pseudorandom 64-bit (possibly negative) `i64`.
-[inline]
-pub fn (mut rng SplitMix64RNG) i64() i64 {
-	return i64(rng.u64())
-}
-
-// int31 returns a positive pseudorandom 31-bit `int`.
-[inline]
-pub fn (mut rng SplitMix64RNG) int31() int {
-	return int(rng.u32() & constants.u31_mask) // Set the 32nd bit to 0.
-}
-
-// int63 returns a positive pseudorandom 63-bit `i64`.
-[inline]
-pub fn (mut rng SplitMix64RNG) int63() i64 {
-	return i64(rng.u64() & constants.u63_mask) // Set the 64th bit to 0.
-}
-
-// intn returns a pseudorandom `int` in range `[0, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) intn(max int) int {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return int(rng.u32n(u32(max)))
-}
-
-// i64n returns a pseudorandom `i64` in range `[0, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) i64n(max i64) i64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return i64(rng.u64n(u64(max)))
-}
-
-// int_in_range returns a pseudorandom `int` in range `[min, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) int_in_range(min int, max int) int {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	// This supports negative ranges like [-10, -5) because the difference is positive
-	return min + rng.intn(max - min)
-}
-
-// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) i64_in_range(min i64, max i64) i64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.i64n(max - min)
-}
-
-// f32 returns a pseudorandom `f32` value in range `[0, 1)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) f32() f32 {
-	return f32(rng.u32()) / constants.max_u32_as_f32
-}
-
-// f64 returns a pseudorandom `f64` value in range `[0, 1)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) f64() f64 {
-	return f64(rng.u64()) / constants.max_u64_as_f64
-}
-
-// f32n returns a pseudorandom `f32` value in range `[0, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) f32n(max f32) f32 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f32() * max
-}
-
-// f64n returns a pseudorandom `f64` value in range `[0, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) f64n(max f64) f64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f64() * max
-}
-
-// f32_in_range returns a pseudorandom `f32` in range `[min, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) f32_in_range(min f32, max f32) f32 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.f32n(max - min)
-}
-
-// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
-[inline]
-pub fn (mut rng SplitMix64RNG) f64_in_range(min f64, max f64) f64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.f64n(max - min)
-}
-
 // free should be called when the generator is no longer needed
 [unsafe]
 pub fn (mut rng SplitMix64RNG) free() {

vlib/rand/splitmix64/splitmix64_test.v

@@ -1,4 +1,5 @@
 import math
+import rand
 import rand.splitmix64
 import rand.seed
 
@@ -17,10 +18,10 @@ const (
 fn gen_randoms(seed_data []u32, bound int) []u64 {
 	bound_u64 := u64(bound)
 	mut randoms := []u64{len: (20)}
-	mut rnd := splitmix64.SplitMix64RNG{}
+	mut rnd := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 	rnd.seed(seed_data)
 	for i in 0 .. 20 {
-		randoms[i] = rnd.u64n(bound_u64)
+		randoms[i] = rnd.u64n(bound_u64) or { panic("Couldn't obtain u64") }
 	}
 	return randoms
 }
@@ -36,40 +37,29 @@ fn test_splitmix64_reproducibility() {
 	}
 }
 
-// TODO: use the `in` syntax and remove this function
-// after generics has been completely implemented
-fn found(value u64, arr []u64) bool {
-	for item in arr {
-		if value == item {
-			return true
-		}
-	}
-	return false
-}
-
 fn test_splitmix64_variability() {
 	// If this test fails and if it is certainly not the implementation
 	// at fault, try changing the seed values. Repeated values are
 	// improbable but not impossible.
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		mut values := []u64{cap: value_count}
 		for i in 0 .. value_count {
 			value := rng.u64()
-			assert !found(value, values)
+			assert value !in values
 			assert values.len == i
 			values << value
 		}
 	}
 }
 
-fn check_uniformity_u64(mut rng splitmix64.SplitMix64RNG, range u64) {
+fn check_uniformity_u64(mut rng rand.PRNG, range u64) {
 	range_f64 := f64(range)
 	expected_mean := range_f64 / 2.0
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
-		diff := f64(rng.u64n(range)) - expected_mean
+		diff := f64(rng.u64n(range) or { panic("Couldn't obtain u64") }) - expected_mean
 		variance += diff * diff
 	}
 	variance /= sample_size - 1
@@ -82,7 +72,7 @@ fn check_uniformity_u64(mut rng splitmix64.SplitMix64RNG, range u64) {
 fn test_splitmix64_uniformity_u64() {
 	ranges := [14019545, 80240, 130]
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for range in ranges {
 			check_uniformity_u64(mut rng, u64(range))
@@ -90,7 +80,7 @@ fn test_splitmix64_uniformity_u64() {
 	}
 }
 
-fn check_uniformity_f64(mut rng splitmix64.SplitMix64RNG) {
+fn check_uniformity_f64(mut rng rand.PRNG) {
 	expected_mean := 0.5
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
@@ -107,7 +97,7 @@ fn check_uniformity_f64(mut rng splitmix64.SplitMix64RNG) {
 fn test_splitmix64_uniformity_f64() {
 	// The f64 version
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		check_uniformity_f64(mut rng)
 	}
@@ -116,10 +106,10 @@ fn test_splitmix64_uniformity_f64() {
 fn test_splitmix64_u32n() {
 	max := u32(16384)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32n(max)
+			value := rng.u32n(max) or { panic("Couldn't obtain u32") }
 			assert value >= 0
 			assert value < max
 		}
@@ -129,10 +119,10 @@ fn test_splitmix64_u32n() {
 fn test_splitmix64_u64n() {
 	max := u64(379091181005)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64n(max)
+			value := rng.u64n(max) or { panic("Couldn't obtain u64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -143,10 +133,10 @@ fn test_splitmix64_u32_in_range() {
 	max := u32(484468466)
 	min := u32(316846)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32_in_range(min, max)
+			value := rng.u32_in_range(min, max) or { panic("Couldn't obtain u32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -157,10 +147,10 @@ fn test_splitmix64_u64_in_range() {
 	max := u64(216468454685163)
 	min := u64(6848646868)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64_in_range(min, max)
+			value := rng.u64_in_range(min, max) or { panic("Couldn't obtain u64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -171,7 +161,7 @@ fn test_splitmix64_int31() {
 	max_u31 := int(0x7FFFFFFF)
 	sign_mask := int(0x80000000)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int31()
@@ -187,7 +177,7 @@ fn test_splitmix64_int63() {
 	max_u63 := i64(0x7FFFFFFFFFFFFFFF)
 	sign_mask := i64(0x8000000000000000)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int63()
@@ -201,10 +191,10 @@ fn test_splitmix64_int63() {
 fn test_splitmix64_intn() {
 	max := 2525642
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.intn(max)
+			value := rng.intn(max) or { panic("Couldn't obtain int") }
 			assert value >= 0
 			assert value < max
 		}
@@ -214,10 +204,10 @@ fn test_splitmix64_intn() {
 fn test_splitmix64_i64n() {
 	max := i64(3246727724653636)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64n(max)
+			value := rng.i64n(max) or { panic("Couldn't obtain i64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -228,10 +218,10 @@ fn test_splitmix64_int_in_range() {
 	min := -4252
 	max := 230549862
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.int_in_range(min, max)
+			value := rng.int_in_range(min, max) or { panic("Couldn't obtain int in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -242,10 +232,10 @@ fn test_splitmix64_i64_in_range() {
 	min := i64(-24095)
 	max := i64(324058)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64_in_range(min, max)
+			value := rng.i64_in_range(min, max) or { panic("Couldn't obtain i64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -254,7 +244,7 @@ fn test_splitmix64_i64_in_range() {
 
 fn test_splitmix64_f32() {
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f32()
@@ -266,7 +256,7 @@ fn test_splitmix64_f32() {
 
 fn test_splitmix64_f64() {
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f64()
@@ -279,10 +269,10 @@ fn test_splitmix64_f64() {
 fn test_splitmix64_f32n() {
 	max := f32(357.0)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32n(max)
+			value := rng.f32n(max) or { panic("Couldn't obtain f32") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -292,10 +282,10 @@ fn test_splitmix64_f32n() {
 fn test_splitmix64_f64n() {
 	max := 1.52e6
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64n(max)
+			value := rng.f64n(max) or { panic("Couldn't obtain f64") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -306,10 +296,10 @@ fn test_splitmix64_f32_in_range() {
 	min := f32(-24.0)
 	max := f32(125.0)
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32_in_range(min, max)
+			value := rng.f32_in_range(min, max) or { panic("Couldn't obtain f32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -320,10 +310,10 @@ fn test_splitmix64_f64_in_range() {
 	min := -548.7
 	max := 5015.2
 	for seed in seeds {
-		mut rng := splitmix64.SplitMix64RNG{}
+		mut rng := &rand.PRNG(&splitmix64.SplitMix64RNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64_in_range(min, max)
+			value := rng.f64_in_range(min, max) or { panic("Couldn't obtain f64 in range") }
 			assert value >= min
 			assert value < max
 		}

vlib/rand/sys/system_rng.c.v

@@ -5,7 +5,6 @@ module sys
 
 import math.bits
 import rand.seed
-import rand.constants
 
 // Implementation note:
 // ====================
@@ -76,204 +75,6 @@ pub fn (r SysRNG) u64() u64 {
 	return result
 }
 
-// r.u32n(max) returns a pseudorandom u32 value that is guaranteed to be less than max
-[inline]
-pub fn (r SysRNG) u32n(max u32) u32 {
-	if max == 0 {
-		eprintln('max must be positive integer')
-		exit(1)
-	}
-	// Owing to the pigeon-hole principle, we can't simply do
-	// val := rng.u32() % max.
-	// It'll wreck the properties of the distribution unless
-	// max evenly divides 2^32. So we divide evenly to
-	// the closest power of two. Then we loop until we find
-	// an int in the required range
-	bit_len := bits.len_32(max)
-	if bit_len == 32 {
-		for {
-			value := r.u32()
-			if value < max {
-				return value
-			}
-		}
-	} else {
-		mask := (u32(1) << (bit_len + 1)) - 1
-		for {
-			value := r.u32() & mask
-			if value < max {
-				return value
-			}
-		}
-	}
-	return u32(0)
-}
-
-// r.u64n(max) returns a pseudorandom u64 value that is guaranteed to be less than max
-[inline]
-pub fn (r SysRNG) u64n(max u64) u64 {
-	if max == 0 {
-		eprintln('max must be positive integer')
-		exit(1)
-	}
-	// Similar procedure for u64s
-	bit_len := bits.len_64(max)
-	if bit_len == 64 {
-		for {
-			value := r.u64()
-			if value < max {
-				return value
-			}
-		}
-	} else {
-		mask := (u64(1) << (bit_len + 1)) - 1
-		for {
-			value := r.u64() & mask
-			if value < max {
-				return value
-			}
-		}
-	}
-	return u64(0)
-}
-
-// r.u32n(min, max) returns a pseudorandom u32 value that is guaranteed to be in [min, max)
-[inline]
-pub fn (r SysRNG) u32_in_range(min u32, max u32) u32 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + r.u32n(max - min)
-}
-
-// r.u64n(min, max) returns a pseudorandom u64 value that is guaranteed to be in [min, max)
-[inline]
-pub fn (r SysRNG) u64_in_range(min u64, max u64) u64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + r.u64n(max - min)
-}
-
-// r.int() returns a pseudorandom 32-bit int (which may be negative)
-[inline]
-pub fn (r SysRNG) int() int {
-	return int(r.u32())
-}
-
-// r.i64() returns a pseudorandom 64-bit i64 (which may be negative)
-[inline]
-pub fn (r SysRNG) i64() i64 {
-	return i64(r.u64())
-}
-
-// r.int31() returns a pseudorandom 31-bit int which is non-negative
-[inline]
-pub fn (r SysRNG) int31() int {
-	return int(r.u32() & constants.u31_mask) // Set the 32nd bit to 0.
-}
-
-// r.int63() returns a pseudorandom 63-bit int which is non-negative
-[inline]
-pub fn (r SysRNG) int63() i64 {
-	return i64(r.u64() & constants.u63_mask) // Set the 64th bit to 0.
-}
-
-// r.intn(max) returns a pseudorandom int that lies in [0, max)
-[inline]
-pub fn (r SysRNG) intn(max int) int {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return int(r.u32n(u32(max)))
-}
-
-// r.i64n(max) returns a pseudorandom i64 that lies in [0, max)
-[inline]
-pub fn (r SysRNG) i64n(max i64) i64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return i64(r.u64n(u64(max)))
-}
-
-// r.int_in_range(min, max) returns a pseudorandom int that lies in [min, max)
-[inline]
-pub fn (r SysRNG) int_in_range(min int, max int) int {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	// This supports negative ranges like [-10, -5) because the difference is positive
-	return min + r.intn(max - min)
-}
-
-// r.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
-[inline]
-pub fn (r SysRNG) i64_in_range(min i64, max i64) i64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + r.i64n(max - min)
-}
-
-// r.f32() returns a pseudorandom f32 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
-[inline]
-pub fn (r SysRNG) f32() f32 {
-	return f32(r.u32()) / constants.max_u32_as_f32
-}
-
-// r.f64() returns a pseudorandom f64 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
-[inline]
-pub fn (r SysRNG) f64() f64 {
-	return f64(r.u64()) / constants.max_u64_as_f64
-}
-
-// r.f32n() returns a pseudorandom f32 value in [0, max)
-[inline]
-pub fn (r SysRNG) f32n(max f32) f32 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return r.f32() * max
-}
-
-// r.f64n() returns a pseudorandom f64 value in [0, max)
-[inline]
-pub fn (r SysRNG) f64n(max f64) f64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return r.f64() * max
-}
-
-// r.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max)
-[inline]
-pub fn (r SysRNG) f32_in_range(min f32, max f32) f32 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + r.f32n(max - min)
-}
-
-// r.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
-[inline]
-pub fn (r SysRNG) f64_in_range(min f64, max f64) f64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + r.f64n(max - min)
-}
-
 // free should be called when the generator is no longer needed
 [unsafe]
 pub fn (mut rng SysRNG) free() {

vlib/rand/sys/system_rng_test.v

@@ -1,4 +1,5 @@
 import math
+import rand
 import rand.sys
 
 const (
@@ -13,7 +14,7 @@ const (
 	inv_sqrt_12   = 1.0 / math.sqrt(12)
 )
 
-fn get_n_randoms(n int, r sys.SysRNG) []int {
+fn get_n_randoms(n int, mut r rand.PRNG) []int {
 	mut ints := []int{cap: n}
 	for _ in 0 .. n {
 		ints << r.int()
@@ -28,51 +29,40 @@ fn test_sys_rng_reproducibility() {
 	// seed for another batch of data.
 	for seed in seeds {
 		seed_data := [seed]
-		mut r1 := sys.SysRNG{}
+		mut r1 := &rand.PRNG(&sys.SysRNG{})
-		mut r2 := sys.SysRNG{}
+		mut r2 := &rand.PRNG(&sys.SysRNG{})
 		r1.seed(seed_data)
-		ints1 := get_n_randoms(value_count, r1)
+		ints1 := get_n_randoms(value_count, mut r1)
 		r2.seed(seed_data)
-		ints2 := get_n_randoms(value_count, r2)
+		ints2 := get_n_randoms(value_count, mut r2)
 		assert ints1 == ints2
 	}
 }
 
-// TODO: use the `in` syntax and remove this function
-// after generics has been completely implemented
-fn found(value u64, arr []u64) bool {
-	for item in arr {
-		if value == item {
-			return true
-		}
-	}
-	return false
-}
-
 fn test_sys_rng_variability() {
 	// If this test fails and if it is certainly not the implementation
 	// at fault, try changing the seed values. Repeated values are
 	// improbable but not impossible.
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		mut values := []u64{cap: value_count}
 		for i in 0 .. value_count {
 			value := rng.u64()
-			assert !found(value, values)
+			assert value !in values
 			assert values.len == i
 			values << value
 		}
 	}
 }
 
-fn check_uniformity_u64(rng sys.SysRNG, range u64) {
+fn check_uniformity_u64(mut rng rand.PRNG, range u64) {
 	range_f64 := f64(range)
 	expected_mean := range_f64 / 2.0
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
-		diff := f64(rng.u64n(range)) - expected_mean
+		diff := f64(rng.u64n(range) or { panic("Couldn't obtain u64") }) - expected_mean
 		variance += diff * diff
 	}
 	variance /= sample_size - 1
@@ -88,15 +78,15 @@ fn test_sys_rng_uniformity_u64() {
 	ranges := [14019545, 80240, 130]
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for range in ranges {
-			check_uniformity_u64(rng, u64(range))
+			check_uniformity_u64(mut rng, u64(range))
 		}
 	}
 }
 
-fn check_uniformity_f64(rng sys.SysRNG) {
+fn check_uniformity_f64(mut rng rand.PRNG) {
 	expected_mean := 0.5
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
@@ -114,9 +104,9 @@ fn test_sys_rng_uniformity_f64() {
 	// The f64 version
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
-		check_uniformity_f64(rng)
+		check_uniformity_f64(mut rng)
 	}
 }
 
@@ -124,10 +114,10 @@ fn test_sys_rng_u32n() {
 	max := u32(16384)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.u32n(max)
+			value := rng.u32n(max) or { panic("Couldn't obtain u32") }
 			assert value >= 0
 			assert value < max
 		}
@@ -138,10 +128,10 @@ fn test_sys_rng_u64n() {
 	max := u64(379091181005)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.u64n(max)
+			value := rng.u64n(max) or { panic("Couldn't obtain u64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -153,10 +143,10 @@ fn test_sys_rng_u32_in_range() {
 	min := u32(316846)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.u32_in_range(min, max)
+			value := rng.u32_in_range(min, max) or { panic("Couldn't obtain u32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -168,10 +158,10 @@ fn test_sys_rng_u64_in_range() {
 	min := u64(6848646868)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.u64_in_range(min, max)
+			value := rng.u64_in_range(min, max) or { panic("Couldn't obtain u64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -182,10 +172,10 @@ fn test_sys_rng_intn() {
 	max := 2525642
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.intn(max)
+			value := rng.intn(max) or { panic("Couldn't obtain int") }
 			assert value >= 0
 			assert value < max
 		}
@@ -196,10 +186,10 @@ fn test_sys_rng_i64n() {
 	max := i64(3246727724653636)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.i64n(max)
+			value := rng.i64n(max) or { panic("Couldn't obtain i64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -211,10 +201,10 @@ fn test_sys_rng_int_in_range() {
 	max := 23054962
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.int_in_range(min, max)
+			value := rng.int_in_range(min, max) or { panic("Couldn't obtain int in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -226,10 +216,10 @@ fn test_sys_rng_i64_in_range() {
 	max := i64(324058)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.i64_in_range(min, max)
+			value := rng.i64_in_range(min, max) or { panic("Couldn't obtain i64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -241,7 +231,7 @@ fn test_sys_rng_int31() {
 	sign_mask := int(0x80000000)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
 			value := rng.int31()
@@ -258,7 +248,7 @@ fn test_sys_rng_int63() {
 	sign_mask := i64(0x8000000000000000)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
 			value := rng.int63()
@@ -272,7 +262,7 @@ fn test_sys_rng_int63() {
 fn test_sys_rng_f32() {
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
 			value := rng.f32()
@@ -285,7 +275,7 @@ fn test_sys_rng_f32() {
 fn test_sys_rng_f64() {
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
 			value := rng.f64()
@@ -299,10 +289,10 @@ fn test_sys_rng_f32n() {
 	max := f32(357.0)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.f32n(max)
+			value := rng.f32n(max) or { panic("Couldn't obtain f32") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -313,10 +303,10 @@ fn test_sys_rng_f64n() {
 	max := 1.52e6
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.f64n(max)
+			value := rng.f64n(max) or { panic("Couldn't obtain f64") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -328,10 +318,10 @@ fn test_sys_rng_f32_in_range() {
 	max := f32(125.0)
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.f32_in_range(min, max)
+			value := rng.f32_in_range(min, max) or { panic("Couldn't obtain f32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -343,10 +333,10 @@ fn test_sys_rng_f64_in_range() {
 	max := 5015.2
 	for seed in seeds {
 		seed_data := [seed]
-		mut rng := sys.SysRNG{}
+		mut rng := &rand.PRNG(&sys.SysRNG{})
 		rng.seed(seed_data)
 		for _ in 0 .. range_limit {
-			value := rng.f64_in_range(min, max)
+			value := rng.f64_in_range(min, max) or { panic("Couldn't obtain f64 in range") }
 			assert value >= min
 			assert value < max
 		}

vlib/rand/util/util.v

@@ -30,7 +30,7 @@ pub fn sample_r<T>(array []T, k int) []T {
 	n := array.len
 	mut results := []T{len: k}
 	for i in 0 .. k {
-		results[i] = array[rand.intn(n)]
+		results[i] = array[rand.intn(n) or { 0 }]
 	}
 	return results
 }
@@ -43,7 +43,7 @@ pub fn shuffle<T>(mut a []T, n int) {
 	}
 	cnt := if n == 0 { a.len - 1 } else { n }
 	for i in 0 .. cnt {
-		x := rand.int_in_range(i, a.len)
+		x := rand.int_in_range(i, a.len) or { 0 }
 		// swap
 		a_i := a[i]
 		a[i] = a[x]

vlib/rand/wyrand/wyrand.v

@@ -3,7 +3,6 @@
 // that can be found in the LICENSE file.
 module wyrand
 
-import math.bits
 import rand.seed
 import rand.constants
 import hash
@@ -58,195 +57,3 @@ pub fn (mut rng WyRandRNG) u64() u64 {
 	}
 	return 0
 }
-
-// u32n returns a pseudorandom `u32` less than `max`.
-[inline]
-pub fn (mut rng WyRandRNG) u32n(max u32) u32 {
-	if max == 0 {
-		eprintln('max must be positive integer')
-		exit(1)
-	}
-	// Check SysRNG in system_rng.c.v for explanation
-	bit_len := bits.len_32(max)
-	if bit_len == 32 {
-		for {
-			value := rng.u32()
-			if value < max {
-				return value
-			}
-		}
-	} else {
-		mask := (u32(1) << (bit_len + 1)) - 1
-		for {
-			value := rng.u32() & mask
-			if value < max {
-				return value
-			}
-		}
-	}
-	return u32(0)
-}
-
-// u64n returns a pseudorandom `u64` less than `max`.
-[inline]
-pub fn (mut rng WyRandRNG) u64n(max u64) u64 {
-	if max == 0 {
-		eprintln('max must be positive integer')
-		exit(1)
-	}
-	bit_len := bits.len_64(max)
-	if bit_len == 64 {
-		for {
-			value := rng.u64()
-			if value < max {
-				return value
-			}
-		}
-	} else {
-		mask := (u64(1) << (bit_len + 1)) - 1
-		for {
-			value := rng.u64() & mask
-			if value < max {
-				return value
-			}
-		}
-	}
-	return u64(0)
-}
-
-// u32n returns a pseudorandom `u32` value that is guaranteed to be in range `[min, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) u32_in_range(min u32, max u32) u32 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.u32n(max - min)
-}
-
-// u64n returns a pseudorandom `u64` value that is guaranteed to be in range `[min, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) u64_in_range(min u64, max u64) u64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.u64n(max - min)
-}
-
-// int returns a (possibly negative) pseudorandom 32-bit `int`.
-[inline]
-pub fn (mut rng WyRandRNG) int() int {
-	return int(rng.u32())
-}
-
-// i64 returns a (possibly negative) pseudorandom 64-bit `i64`.
-[inline]
-pub fn (mut rng WyRandRNG) i64() i64 {
-	return i64(rng.u64())
-}
-
-// int31 returns a positive pseudorandom 31-bit `int`.
-[inline]
-pub fn (mut rng WyRandRNG) int31() int {
-	return int(rng.u32() & constants.u31_mask) // Set the 32nd bit to 0.
-}
-
-// int63 returns a positive pseudorandom 63-bit `i64`.
-[inline]
-pub fn (mut rng WyRandRNG) int63() i64 {
-	return i64(rng.u64() & constants.u63_mask) // Set the 64th bit to 0.
-}
-
-// intn returns a pseudorandom `int` in range `[0, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) intn(max int) int {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return int(rng.u32n(u32(max)))
-}
-
-// i64n returns a pseudorandom int that lies in `[0, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) i64n(max i64) i64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return i64(rng.u64n(u64(max)))
-}
-
-// int_in_range returns a pseudorandom `int` in range `[min, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) int_in_range(min int, max int) int {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	// This supports negative ranges like [-10, -5) because the difference is positive
-	return min + rng.intn(max - min)
-}
-
-// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) i64_in_range(min i64, max i64) i64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.i64n(max - min)
-}
-
-// f32 returns a pseudorandom `f32` value in range `[0, 1)`.
-[inline]
-pub fn (mut rng WyRandRNG) f32() f32 {
-	return f32(rng.u32()) / constants.max_u32_as_f32
-}
-
-// f64 returns a pseudorandom `f64` value in range `[0, 1)`.
-[inline]
-pub fn (mut rng WyRandRNG) f64() f64 {
-	return f64(rng.u64()) / constants.max_u64_as_f64
-}
-
-// f32n returns a pseudorandom `f32` value in range `[0, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) f32n(max f32) f32 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f32() * max
-}
-
-// f64n returns a pseudorandom `f64` value in range `[0, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) f64n(max f64) f64 {
-	if max <= 0 {
-		eprintln('max has to be positive.')
-		exit(1)
-	}
-	return rng.f64() * max
-}
-
-// f32_in_range returns a pseudorandom `f32` in range `[min, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) f32_in_range(min f32, max f32) f32 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.f32n(max - min)
-}
-
-// i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
-[inline]
-pub fn (mut rng WyRandRNG) f64_in_range(min f64, max f64) f64 {
-	if max <= min {
-		eprintln('max must be greater than min')
-		exit(1)
-	}
-	return min + rng.f64n(max - min)
-}

vlib/rand/wyrand/wyrand_test.v

@@ -1,4 +1,5 @@
 import math
+import rand
 import rand.seed
 import rand.wyrand
 
@@ -17,10 +18,10 @@ const (
 fn gen_randoms(seed_data []u32, bound int) []u64 {
 	bound_u64 := u64(bound)
 	mut randoms := []u64{len: (20)}
-	mut rnd := wyrand.WyRandRNG{}
+	mut rnd := &rand.PRNG(&wyrand.WyRandRNG{})
 	rnd.seed(seed_data)
 	for i in 0 .. 20 {
-		randoms[i] = rnd.u64n(bound_u64)
+		randoms[i] = rnd.u64n(bound_u64) or { panic("Couldn't obtain u64") }
 	}
 	return randoms
 }
@@ -36,40 +37,29 @@ fn test_wyrand_reproducibility() {
 	}
 }
 
-// TODO: use the `in` syntax and remove this function
-// after generics has been completely implemented
-fn found(value u64, arr []u64) bool {
-	for item in arr {
-		if value == item {
-			return true
-		}
-	}
-	return false
-}
-
 fn test_wyrand_variability() {
 	// If this test fails and if it is certainly not the implementation
 	// at fault, try changing the seed values. Repeated values are
 	// improbable but not impossible.
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		mut values := []u64{cap: value_count}
 		for i in 0 .. value_count {
 			value := rng.u64()
-			assert !found(value, values)
+			assert value !in values
 			assert values.len == i
 			values << value
 		}
 	}
 }
 
-fn check_uniformity_u64(mut rng wyrand.WyRandRNG, range u64) {
+fn check_uniformity_u64(mut rng rand.PRNG, range u64) {
 	range_f64 := f64(range)
 	expected_mean := range_f64 / 2.0
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
-		diff := f64(rng.u64n(range)) - expected_mean
+		diff := f64(rng.u64n(range) or { panic("Couldn't obtain u64") }) - expected_mean
 		variance += diff * diff
 	}
 	variance /= sample_size - 1
@@ -82,7 +72,7 @@ fn check_uniformity_u64(mut rng wyrand.WyRandRNG, range u64) {
 fn test_wyrand_uniformity_u64() {
 	ranges := [14019545, 80240, 130]
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for range in ranges {
 			check_uniformity_u64(mut rng, u64(range))
@@ -90,7 +80,7 @@ fn test_wyrand_uniformity_u64() {
 	}
 }
 
-fn check_uniformity_f64(mut rng wyrand.WyRandRNG) {
+fn check_uniformity_f64(mut rng rand.PRNG) {
 	expected_mean := 0.5
 	mut variance := 0.0
 	for _ in 0 .. sample_size {
@@ -107,7 +97,7 @@ fn check_uniformity_f64(mut rng wyrand.WyRandRNG) {
 fn test_wyrand_uniformity_f64() {
 	// The f64 version
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		check_uniformity_f64(mut rng)
 	}
@@ -116,10 +106,10 @@ fn test_wyrand_uniformity_f64() {
 fn test_wyrand_u32n() {
 	max := u32(16384)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32n(max)
+			value := rng.u32n(max) or { panic("Couldn't obtain u32") }
 			assert value >= 0
 			assert value < max
 		}
@@ -129,10 +119,10 @@ fn test_wyrand_u32n() {
 fn test_wyrand_u64n() {
 	max := u64(379091181005)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64n(max)
+			value := rng.u64n(max) or { panic("Couldn't obtain u64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -143,10 +133,10 @@ fn test_wyrand_u32_in_range() {
 	max := u32(484468466)
 	min := u32(316846)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u32_in_range(min, max)
+			value := rng.u32_in_range(min, max) or { panic("Couldn't obtain u32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -157,10 +147,10 @@ fn test_wyrand_u64_in_range() {
 	max := u64(216468454685163)
 	min := u64(6848646868)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.u64_in_range(min, max)
+			value := rng.u64_in_range(min, max) or { panic("Couldn't obtain u64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -171,7 +161,7 @@ fn test_wyrand_int31() {
 	max_u31 := int(0x7FFFFFFF)
 	sign_mask := int(0x80000000)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int31()
@@ -187,7 +177,7 @@ fn test_wyrand_int63() {
 	max_u63 := i64(0x7FFFFFFFFFFFFFFF)
 	sign_mask := i64(0x8000000000000000)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.int63()
@@ -201,10 +191,10 @@ fn test_wyrand_int63() {
 fn test_wyrand_intn() {
 	max := 2525642
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.intn(max)
+			value := rng.intn(max) or { panic("Couldn't obtain int") }
 			assert value >= 0
 			assert value < max
 		}
@@ -214,10 +204,10 @@ fn test_wyrand_intn() {
 fn test_wyrand_i64n() {
 	max := i64(3246727724653636)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64n(max)
+			value := rng.i64n(max) or { panic("Couldn't obtain i64") }
 			assert value >= 0
 			assert value < max
 		}
@@ -228,10 +218,10 @@ fn test_wyrand_int_in_range() {
 	min := -4252
 	max := 1034
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.int_in_range(min, max)
+			value := rng.int_in_range(min, max) or { panic("Couldn't obtain int in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -242,10 +232,10 @@ fn test_wyrand_i64_in_range() {
 	min := i64(-24095)
 	max := i64(324058)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.i64_in_range(min, max)
+			value := rng.i64_in_range(min, max) or { panic("Couldn't obtain i64 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -254,7 +244,7 @@ fn test_wyrand_i64_in_range() {
 
 fn test_wyrand_f32() {
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f32()
@@ -266,7 +256,7 @@ fn test_wyrand_f32() {
 
 fn test_wyrand_f64() {
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
 			value := rng.f64()
@@ -279,10 +269,10 @@ fn test_wyrand_f64() {
 fn test_wyrand_f32n() {
 	max := f32(357.0)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32n(max)
+			value := rng.f32n(max) or { panic("Couldn't obtain f32") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -292,10 +282,10 @@ fn test_wyrand_f32n() {
 fn test_wyrand_f64n() {
 	max := 1.52e6
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64n(max)
+			value := rng.f64n(max) or { panic("Couldn't obtain f64") }
 			assert value >= 0.0
 			assert value < max
 		}
@@ -306,10 +296,10 @@ fn test_wyrand_f32_in_range() {
 	min := f32(-24.0)
 	max := f32(125.0)
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f32_in_range(min, max)
+			value := rng.f32_in_range(min, max) or { panic("Couldn't obtain f32 in range") }
 			assert value >= min
 			assert value < max
 		}
@@ -320,10 +310,10 @@ fn test_wyrand_f64_in_range() {
 	min := -548.7
 	max := 5015.2
 	for seed in seeds {
-		mut rng := wyrand.WyRandRNG{}
+		mut rng := &rand.PRNG(&wyrand.WyRandRNG{})
 		rng.seed(seed)
 		for _ in 0 .. range_limit {
-			value := rng.f64_in_range(min, max)
+			value := rng.f64_in_range(min, max) or { panic("Couldn't obtain f64 in range") }
 			assert value >= min
 			assert value < max
 		}

vlib/sync/channels.c.v

@@ -592,10 +592,10 @@ pub fn channel_select(mut channels []&Channel, dir []Direction, mut objrefs []vo
 	mut event_idx := -1 // negative index means `timed out`
 
 	outer: for {
-		rnd := rand.u32_in_range(0, u32(channels.len))
+		rnd := rand.intn(channels.len) or { 0 }
 		mut num_closed := 0
 		for j, _ in channels {
-			mut i := j + int(rnd)
+			mut i := j + rnd
 			if i >= channels.len {
 				i -= channels.len
 			}

vlib/time/misc/misc.v

@@ -9,5 +9,5 @@ const (
 
 // random returns a random time struct in *the past*.
 pub fn random() time.Time {
-	return time.unix(int(rand.i64n(misc.start_time_unix)))
+	return time.unix(int(rand.i64n(misc.start_time_unix) or { 0 }))
 }

vlib/v/tests/const_init_order_test.v

@@ -1,7 +1,7 @@
 import rand
 
 const (
-	my_random_letter_const = byte(65 + rand.u32n(25))
+	my_random_letter_const = byte(65) + (rand.byte() % 26)
 )
 
 fn test_rand_is_initialized_before_main() {

vlib/v/tests/generics_with_recursive_generics_fn_test.v

@@ -8,7 +8,7 @@ const (
 fn test_generics_with_recursive_generics_fn() {
 	mut arr := []int{}
 	for _ in 0 .. gen_len {
-		arr << rand.intn(gen_max)
+		arr << rand.intn(gen_max) or { 0 }
 	}
 	println('before quick sort whether array is sorted: ${is_sorted<int>(arr)}')
 	assert !is_sorted<int>(arr)

vlib/v/tests/keep_args_alive_test.v

@@ -49,9 +49,9 @@ fn tt(mut sem sync.Semaphore) int {
 fn waste_mem(n int, mut sem sync.Semaphore) {
 	mut m := []voidptr{len: 30}
 	for j := 0; n < 0 || j < n; j++ {
-		i := rand.intn(30)
+		i := rand.intn(30) or { 0 }
 		m[i] = unsafe { malloc(10000) }
-		fill := rand.intn(256)
+		fill := rand.intn(256) or { 0 }
 		unsafe { C.memset(m[i], fill, 10000) }
 		if n < 0 && sem.try_wait() {
 			break

vlib/v/tests/valgrind/rand_module.v

@@ -1,7 +1,7 @@
 import rand
 
 fn main() {
-	n := rand.intn(1000)
+	n := rand.intn(1000) or { 0 }
 	println(n)
 	u := rand.uuid_v4()
 	println(u)