Abstract type: Difference between revisions
→{{header|Go}}: Rejigged this entry which didn't quite hang together previously.
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=={{header|Go}}==
Go's ''interface type'' is an abstract type. It defines a set of methods that a
<lang go>interface {▼
Name() string▼
SetName(name string)▼
A variable of an interface type can hold a value of any type that implements the methods that are specified in the interface. You don't need to explicitly "declare" that the type "implements" the interface or anything like that -- the compatibility is purely structural based on the methods.
In the following example, the Dog and Cat types both satisfy the Beast interface because they each have the specified methods. The ''bprint'' function can print details for any Beast.
import "fmt"
type Beast interface {
▲ Name() string
}
type
kind string
}▼
func (d Dog) Kind() string { return d.kind }
func (d Dog) Name() string { return d.name }
func (d Dog) Cry() string { return "Woof" }
type Cat struct {
kind string
name string
}
func (
func (c Cat) Name() string { return c.name }
▲}
▲func (p Pet) Cry() string {
func bprint(
fmt.Printf("%s, who's a %s, cries: %q.\n", b.Name(), b.Kind(), b.Cry())
}
func main() {
d := Dog{"labrador", "Max"}
bprint(d)
bprint(c)
}</lang>
{{out}}
<pre>
Max, who's a labrador, cries: "Woof".
Sammy, who's a siamese, cries: "Meow".
</pre>
=={{header|Groovy}}==
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