Day 3 - Back at it

Let's play with using Rust to process private to public notes.
Leonardo Notebook
| 'Leonardo Notebook' by twid is licensed under CC BY-SA 2.0. |

Project Scope and ToDos

  1. Pull public-marked notes from the notebook to the new repo
  2. Create website that treats them like a wiki and links pages together
  3. Support the basic YAML in

Day 3

Ok, I think I've got stuff basically working!

git commit -am "Adding more conventions."

So I got the object, I can read metadata out of the file. Now I need to do something with that file! Step one, let's copy that file! I may want to edit it at the point of copying it over. I've read the file into a variable, so that should be the first step. Now how to write it?

First I want to check if the YAML public value is true. Hey, is this my first Rust if statement? I think so. Ok, so we cast it as bool and unrap it is what I'm seeing. Let's try that.

    if yamlObj["public"].as_bool().unwrap() {
println!("Public is true");

Hey, it works! Ok, now I want to write it.

Ok, just like node there's a clearly labeled fs library. Looks like it has a basic write function. Let's give it a try!

I've been passing everything (pretty much) by reference. But I'm actually done with this variable, so good behavior would be to actually clear it out when I'm done with it. So I should pass it not by reference, right? Let's try that. I've used expect in the past to handle errors, but the documentation says it isn't the preferred way to handle it. It looks like there is chaining to handle errors instead. Hmmm, whatever the syntax is supposed to be here, I'm not getting it right. I'll have to look around.

Ok, it might not be the right error handling process for this. It looks like perhaps I could use a ? after to early return an error. But that's not great, I want to do something with the error. So a control structure for that appears to be match. It looks like this is the suggested way to handle errors in a recoverable way.

    if yamlObj["public"].as_bool().unwrap() {
println!("Public is true");
let write_result = fs::write("../src/notes/", file_contents);
let written_file = match write_result {
Ok(file) => file,
Err(error) => panic!("Problem opening the file: {:?}", error),

Hey, look at that, I wrote a file! It works!

git commit -am "Write a file, heck yes"

And yeah, if public is false it won't write the file. Good first step!

Ok, what happens if public is not a bool, but is instead one of the directives I'm planning to use? How do I take a value that may or may not be a bool and handle it, optionally turning it into a bool or using it like a bool? I think the right answer is using match?

Maybe not, I think I can use Any and either downcast it or handle it in a Box.