mirror of
https://github.com/vlang/v.git
synced 2023-08-10 21:13:21 +03:00
54 lines
1011 B
V
54 lines
1011 B
V
// declare interface
|
|
interface MyInterface {
|
|
val() int
|
|
}
|
|
|
|
// define struct type
|
|
struct St {
|
|
mut:
|
|
n int
|
|
}
|
|
|
|
// make the struct type implement the interface
|
|
fn (x St) val() int {
|
|
return x.n
|
|
}
|
|
|
|
fn owerwrite_stack() f64 {
|
|
a := 12.5
|
|
b := 3.5
|
|
c := a + b
|
|
return c
|
|
}
|
|
|
|
// nothing special so far, but now some functions that return an interfaces
|
|
// these used to cause memory corruptions, but work with this PR:
|
|
fn gen_interface() MyInterface {
|
|
x := St{
|
|
n: -123
|
|
} // `x`will be allocated on heap
|
|
return x // because an interface object is returned here that contains the address of x
|
|
}
|
|
|
|
fn return_interface(x St) MyInterface {
|
|
// x will be copied to stack (requires #10528)
|
|
return x // because it's address is returned inside the interface
|
|
}
|
|
|
|
fn test_gen_interface() {
|
|
i1 := gen_interface()
|
|
d := owerwrite_stack()
|
|
assert i1.val() == -123
|
|
assert d == 16.0
|
|
}
|
|
|
|
fn test_convert_to_interface() {
|
|
x := St{
|
|
n: 5
|
|
}
|
|
i2 := return_interface(x)
|
|
d := owerwrite_stack()
|
|
assert i2.val() == 5
|
|
assert d == 16.0
|
|
}
|