Add post in draft mode.

posts/2017-12-05-getting-started-with-rust-function-struct-and-ref.md

+extends: post.liquid
+comments: true 
+title: 'Getting started with Rust: Function, struct and ref'
+date: 05 Dec 2017 00:00:00 +0000 
+author: Mathieu Nivoliez 
+draft: true
+lang: en
+---
+Hello everyone! Today we continue on our rust serie, we are going to talk about function and struct.
+
+## "Seems like a lot? Are we really going to cover all this?"
+
+Yes and yes.
+
+In order to do all that, we are going to need a variable, let's define that:
+```rust
+// We want to buy a fallout boy, so lets define a number of caps.
+let caps = 5; 
+```
+We just define a variable caps of value 5.
+
+## "Wait a minute! In the previous post, didn't you said that rust was a strongly typed language?"
+
+I did, and it's true. Let me explain you the beautiful world of type inference!
+At compile time, the rust compiler will try to guess the type of `caps` from its use (assignation or operation).
+I said *try* because, sometimes, the rust compiler will not succeded. For example, if the using of caps not allow to define its type.
+The type inference is here to avoid writting types when it can easily be guessed.
+You still can define type with this syntax:
+```rust
+let caps: usize /* type define here */ = 5;
+```
+
+That said, a variable can be shadowed. Imagine that you got the number of caps in the form of a string, it makes senses to still call it caps. That's what shadowing is about.
+Let me show you:
+```rust
+let caps = "five";
+let caps = get_number_from_string(caps); // caps is now 5
+```
+
+It may not be intuitive yet, but through practice, it will.
+
+## "Ok, but what about this *get_number_from_string* thing?"
+
+Excellent transition, it's almost like if I was writting your line.
+*get_number_from_string* is a function. Let see how we can define it:
+```rust
+fn get_number_from_string( num: &'static str ) -> usize {...}
+```
+
+## "HOLD ON!!!! WHAT IS THIS?????"