45 lines
1.4 KiB
Plaintext
45 lines
1.4 KiB
Plaintext
---
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title: "Rust: todo! macro"
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author: "James Pace"
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date: "2024/01/21"
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---
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One of the features of Rust that I've found really helpful when getting started
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on a project is the `todo!` macro.
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The `todo!` macro tells the compiler that you know that some section of code
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isn't complete yet and that it should compile the rest of it anyway.
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An example of where I've used this is when I get started on a project I like protoyping
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out the signatures for the primary functions I think I'm going to need before I start
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implemententing them.
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For example, if I'm working on functions that do math operations on a custom type,
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I'll start by thinking about what functions I need and what their signatures are
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going to be, type that out, and then fill them in.
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With `todo!`, that means I may type out something like:
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```rust
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struct Point {
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pub x: f32,
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pub y: f32,
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pub z: f32,
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}
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impl Point {
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pub fn add(&self, other: &Point) -> Point {
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todo!()
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}
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pub fn subtract(&self, other: &Point) -> Point {
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todo!()
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}
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}
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```
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and that compiles, as long as there are not other mistakes.
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The reason that's useful is let's say I made a mistake and type `Pint`
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instead of `Point` somewhere.
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I can build the code, have the compiler point that out, and fix it
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before needing to implement everything.
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The official documentation about `todo!` can be found
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[here](https://doc.rust-lang.org/std/macro.todo.html).
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