# 1.0.0[−][src]Macro core::unimplemented

    macro_rules! unimplemented {
        () => { ... };
        ($($arg:tt)+) => { ... };
    }

A standardized placeholder for marking unfinished code.

This can be useful if you are prototyping and are just looking to have your code typecheck, or if you're implementing a trait that requires multiple methods, and you're only planning on using one of them.

# Panics

This will always panic!

# Examples

Here's an example of some in-progress code. We have a trait `Foo`:

    trait Foo {
        fn bar(&self);
        fn baz(&self);
    }Run

We want to implement `Foo` on one of our types, but we also want to work on just `bar()` first. In order for our code to compile, we need to implement `baz()`, so we can use `unimplemented!`:

    struct MyStruct;

    impl Foo for MyStruct {
        fn bar(&self) {
            // implementation goes here
        }

        fn baz(&self) {
            // let's not worry about implementing baz() for now
            unimplemented!();
        }
    }

    fn main() {
        let s = MyStruct;
        s.bar();

        // we aren't even using baz() yet, so this is fine.
    }Run

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)