v/vlib/v/tests/generics_test.v

fn test_todo() {
}

fn simple<T>(p T) T {
	return p
}

fn plus<T>(xxx T, b T) T {
	// x := a
	// y := b
	// ww := ww
	// q := xx + 1
	return xxx + b
}

fn test_generic_fn() {
	assert simple<int>(1) == 1
	assert simple<int>(1 + 0) == 1
	assert simple<string>('g') == 'g'
	assert simple<string>('g') + 'h' == 'gh'
	a := plus<int>(2, 3)
	println(a)
	assert a == 5
	assert plus<int>(10, 1) == 11
	assert plus<string>('a', 'b') == 'ab'
}

fn sum<T>(l []T) T {
	mut r := T(0)
	for e in l {
		r += e
	}
	return r
}

fn test_foo() {
	b := [1, 2, 3]
	assert sum<int>(b) == 6
}

fn create<T>() {
	a := T{}
	println(a.name)
	mut xx := T{}
	xx.name = 'foo'
	println(xx.name)
	assert xx.name == 'foo'
	xx.init()
}

struct User {
mut:
	name string
}

struct City {
mut:
	name string
}

fn (u User) init() {
}

fn (c City) init() {
}

fn mut_arg<T>(mut x T) {
	println(x.name) // = 'foo'
}

fn mut_arg2<T>(mut x T) T {
	println(x.name) // = 'foo'
	return *x
}

fn test_create() {
	create<User>()
	create<City>()
	mut u := User{}
	mut_arg<User>(mut u)
	mut_arg2<User>(mut u)
}

fn return_array<T>(arr []T) []T {
	return arr
}

fn test_return_array() {
	a1 := return_array<int>([1, 2, 3])
	assert a1 == [1, 2, 3]
	a2 := return_array<f64>([1.1, 2.2, 3.3])
	assert a2 == [1.1, 2.2, 3.3]
	a3 := return_array<string>(['a', 'b', 'c'])
	assert a3 == ['a', 'b', 'c']
	a4 := return_array<bool>([true, false, true])
	assert a4 == [true, false, true]
}

/*
fn map_f<T,U>(l []T, f fn(T)U) []U {
	mut r := []U{}
	for e in l {
		r << f(e)
	}
	return r
}

fn foldl<T>(l []T, nil T, f fn(T,T)T) T {
	mut r := nil
	for e in l {
		r = f(r, e)
	}
	return r
}

fn square(x int) int {
	return x*x
}

fn mul_int(x int, y int) int {
	return x*y
}

fn assert_eq<T>(a, b T) {
	r := a == b
	println('$a == $b: ${r.str()}')
	assert r
}

fn print_nice<T>(x T, indent int) {
	mut space := ''
	for _ in 0..indent {
		space = space + ' '
	}
	println('$space$x')
}

fn test_generic_fn() {
	assert_eq(simple(0+1), 1)
	assert_eq(simple('g') + 'h', 'gh')
	assert_eq(sum([5.1,6.2,7.0]), 18.3)
	assert_eq(plus(i64(4), i64(6)), i64(10))
	a := [1,2,3,4]
	b := map_f(a, square)
	assert_eq(sum(b), 30)     // 1+4+9+16 = 30
	assert_eq(foldl(b, 1, mul_int), 576)   // 1*4*9*16 = 576
	print_nice('str', 8)
}

struct Point {
mut:
	x f64
	y f64
}

fn (mut p Point) translate<T>(x, y T) {
	p.x += x
	p.y += y
}

fn test_generic_method() {
	mut p := Point{}
	p.translate(2, 1.0)
	assert p.x == 2.0 && p.y == 1.0
}

fn get_values<T>(i T) []T {
	return [i]
}

fn test_generic_fn_in_for_in_expression() {
	for value in get_values(1) {
		assert value == 1
	}

	for i, val in get_values(0) {
		assert i == val
	}

	for value in get_values('a') {
		assert value == 'a'
	}
}
*/
// test generic struct
struct DB {
	driver string
}

struct Group {
pub mut:
	name       string
	group_name string
}

struct Permission {
pub mut:
	name string
}

struct Repo<T, U> {
	db         DB
pub mut:
	model      T
	permission U
}

// TODO: multiple type generic struct  needs fixing in return for fn
// fn new_repo<T>(db DB) Repo<T,U> {
// return Repo<T,Permission>{db: db}
// }
fn test_generic_struct() {
	mut a := Repo<User, Permission>{
		model: User{
			name: 'joe'
		}
	}
	// a.model.name = 'joe'
	assert a.model.name == 'joe'
	println('a.model.name: $a.model.name')
	mut b := Repo<Group, Permission>{
		permission: Permission{
			name: 'superuser'
		}
	}
	b.model.name = 'admins'
	assert b.model.name == 'admins'
	assert b.permission.name == 'superuser'
	println('b.model.name: $b.model.name')
	println('b.permission.name: $b.permission.name')
	assert typeof(a.model) == 'User'
	assert typeof(b.model) == 'Group'
	println('typeof(a.model): ' + typeof(a.model))
	println('typeof(b.model): ' + typeof(b.model))
	// mut x := new_repo<User>(DB{})
	// x.model.name = 'joe2'
	// println(x.model.name)
}

struct Foo<T> {
pub:
	data T
}

fn (f Foo<int>) value() string {
	return f.data.str()
}

fn test_generic_struct_method() {
	foo_int := Foo<int>{2}
	assert foo_int.value() == '2'
}

/*
struct Abc{ x int y int z int }

fn p<T>(args ...T) {
	size:=sizeof(T)
	print('p called with size: ${size:3d} | ')
	for _,x in args {
		print(x)
		print(' ')
	}
	println('')
	assert true
}

fn test_generic_fn_with_variadics(){
	s:='abc'
	i:=1
	abc:=Abc{1,2,3}
	// these calls should all compile, and print the arguments,
	// even though the arguments are all a different type and arity:
	p(s)
	p(i)
	p(abc)
	p('Good', 'morning', 'world')
}
*/