<p>Just start to learn golang. I apologise if this has been asked before.</p>
<p>I want to define a function that recursively calls itself, <em>inside</em> a function, e.g. a fibonacci function inside another function.</p>
<pre><code>func bar() {
func fib(n int) int {
if n < 2 {
return n
}
return fib(n-1) + fib(n-2)
}
r := fib(10)
// some further work
}
</code></pre>
<p>Of course, the above code has compile error.</p>
<p>Any way I can do this? (Without lifting <code>fib()</code> to top level outside <code>bar()</code>.) Or golang just forbids this style?</p>
<hr/>**评论：**<br/><br/>gargamelus: <pre><pre><code>func bar() {
var fib func(n int) int
fib = func(n int) int {
if n < 2 {
return n
}
return fib(n-1) + fib(n-2)
}
r := fib(10)
fmt.Println(r)
}
</code></pre></pre>jeffrallen: <pre><p>Explanation: This is a rare case in Go where something like a C prototype is needed. At the time you call fib inside the function you are defining, the compiler does not yet know what its signature is. By making the fib variable first, and letting it start with a zero value, when you come back to set it later the thing you set it to (the anonymous function) can refer to it, since it already has a type set.</p>
<p>-jeff</p></pre>justinisrael: <pre><p>One way to solve this is to create "fib" as a variable pointing to a function:</p>
<p><a href="https://play.golang.org/p/HX-dIcPBs7" rel="nofollow">https://play.golang.org/p/HX-dIcPBs7</a></p>
<p>That way the reference to fib exists at the correct scope.</p></pre>flyee: <pre><p>thank you and @gargamelus </p>
<p>this is exactly what i am looking for.</p></pre>
