Macro ctor

macro_rules! ctor {
    (#[ctor $(($($meta:tt)*))?] $(#[$imeta:meta])* pub ( $($extra:tt)* ) $($item:tt)*) => { ... };
    (#[ctor $(($($meta:tt)*))?] $(#[$imeta:meta])* pub $($item:tt)*) => { ... };
    (#[ctor $(($($meta:tt)*))?] $(#[$imeta:meta])* fn $($item:tt)*) => { ... };
    (#[ctor $(($($meta:tt)*))?] $(#[$imeta:meta])* unsafe $($item:tt)*) => { ... };
    (#[ctor $(($($meta:tt)*))?] $(#[$imeta:meta])* static $($item:tt)*) => { ... };
    (#[$imeta:meta] $($rest:tt)*) => { ... };
    (__reorder__($(#[$imeta:meta],)*), #[ctor $(($($meta:tt)*))?] $($rest:tt)*) => { ... };
    (__reorder__($(#[$imeta:meta],)*), #[$imeta2:meta] $($rest:tt)*) => { ... };
}

Parse a #[ctor]-annotated item as if it were a proc-macro.

This macro supports both the fn and static forms of the #[ctor] attribute, including attribute parameters.

ctor! {
  /// Create a ctor with a link section
  #[ctor(link_section = ".ctors")]
  unsafe fn foo() { /* ... */ }
}

ctor! {
  #[ctor]
  static FOO: std::collections::HashMap<u32, String> = unsafe {
    let mut m = std::collections::HashMap::new();
    m.insert(1, "foo".to_string());
    m
  };
}