# Macro synom::preceded [−] [src]

    macro_rules! preceded {
        ($i:expr, $submac:ident!( $($args:tt)* ), $submac2:ident!( $($args2:tt)* )) => { ... };
        ($i:expr, $submac:ident!( $($args:tt)* ), $g:expr) => { ... };
        ($i:expr, $f:expr, $submac:ident!( $($args:tt)* )) => { ... };
        ($i:expr, $f:expr, $g:expr) => { ... };
    }

Parse two things, returning the value of the second.

- Syntax: `preceded!(BEFORE, THING)`
- Output: `THING`

    extern crate syn;
    #[macro_use] extern crate synom;

    use syn::Expr;
    use syn::parse::expr;

    // An expression preceded by ##.
    named!(pound_pound_expr -> Expr,
        preceded!(punct!("##"), expr)
    );

    fn main() {
        let input = "## 1 + 1";

        let parsed = pound_pound_expr(input).expect("pound pound expr");

        println!("{:?}", parsed);
    }

# 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`)