From 8bc64a02e975450209b69ddaf8290c93e514270b Mon Sep 17 00:00:00 2001
From: Marcello Lamonaca <marcello@lamonaca.eu>
Date: Sun, 11 Feb 2024 11:47:23 +0100
Subject: [PATCH] rust: add function pointers notes

---
 docs/languages/rust/rust.md | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/docs/languages/rust/rust.md b/docs/languages/rust/rust.md
index d0febe6..bc218a6 100644
--- a/docs/languages/rust/rust.md
+++ b/docs/languages/rust/rust.md
@@ -1242,6 +1242,23 @@ This technique is mostly useful when passing a closure to a new thread to move t
 let closure = move |param| <expr>;
 ```
 
+## Function Pointers
+
+**Function pointer** types, written using the `fn` keyword, refer to a function whose identity is not necessarily known at compile-time.  
+They can be created via a coercion from both *function items* and *non-capturing closures*.
+
+```rs
+fn add_one(x: usize) -> usize {
+    x + 1
+}
+
+let ptr: fn(usize) -> usize = add_one;
+assert_eq!(ptr(5), 6);
+
+let clos: fn(usize) -> usize = |x| x + 5;
+assert_eq!(clos(5), 10);
+```
+
 ## Iterators
 
 The *iterator pattern* allows to perform some task on a sequence of items in turn. An iterator is responsible for the logic of iterating over each item and determining when the sequence has finished.