Tmp: Difference between revisions

From NovaOrdis Knowledge Base
Jump to navigation Jump to search
(Blanked the page)
Tag: Blanking
 
Line 1: Line 1:
==Passing Interfaces to Functions==


With the example above, we declare a function f() that expects an interface A and we pass a B instance when invoking the function:
<pre>
...
type A interface {
    m()
}
func (b B) m() {
    ...
}
func f(a A) {
    a.m()
}
...
b := B{1}
f(b)
...
</pre>
Note that the B instance can be passed by value (as in the example above) or by reference (as in the example below). Both cases work for reasons explained in the [[#Method_Set_associated_with_the_Pointers_of_a_Type|Method Set associated with the Pointers of a Type]] section:
<pre>
...
b := B{1}
f(&b)
...
</pre>
or (same thing)
<pre>
...
bPtr := new(B)
f(bPtr)
...
</pre>
==Interfaces as Fields==
Interfaces can be used as [[Go_Structs#Fields|fields]] in <tt>[[Go_Structs|struct]]</tt>s.
==Implementation Details==
An interface variable is a two-word data structure.
The first word contains a pointer to an internal table called ''iTable'', which contains type information about the stored value: the concrete type of the value that has been stored and a list of methods associated with the value. The second word is a reference to the stored value.
The combination of type information and pointer binds the relationship between the two values.
DEPLETE: [[Go Concepts - The Type System]]

Latest revision as of 22:37, 13 August 2024

Retrieved from "https://kb.novaordis.com/index.php?title=Tmp&oldid=112055"