Methods

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Methods
V does not have classes. But one can define methods for types. A method is a function that has a special receiver argument, only a receiver of the specified type can execute this function. The receiver has its own argument list between fn and the method name.
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struct User {
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    name string
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    email string
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mut:
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    age int
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}
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​
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fn (u User) can_register() bool {
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    return u.age > 15
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}
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​
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fn (u mut User) has_birthday() {
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    u.age += 1
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}
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​
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fn main() {
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    mut bob := User {
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        name: 'Bob'
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        email: '[email protected].com'
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        age: 15
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    }
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    alice := User {
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        name: 'Alice'
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        email: '[email protected]-mail.com'
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        age: 17
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    }
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    println(bob.can_register())                                             // false
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    println('Bob needs to be 16 to register, but he only is ${bob.age}.')   // Bob needs to be 16 to register, but he only is 15.
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    println(alice.can_register())                                           // true
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    bob.has_birthday()
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    println(bob.age)                                                        // 16
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}
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This code above realizes two methods for receivers u of type User. Note that the method has_birthday() has a mut receiver, this is needed here since we want to change its data. The convention of V is not to use receiver names like self, this or similar things but a short, preferably one letter long, name.
Exercises
1.Create a method for the type Person that determines whether a person is underage or not.
2.Create a method that determines whether an Animal has fur or not.
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Last modified 2yr ago
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