Macro diesel::prefix_operator

macro_rules! prefix_operator {
    ($name:ident, $operator:expr) => { ... };
    ($name:ident, $operator:expr, backend: $backend:ty) => { ... };
    ($name:ident, $operator:expr, $return_ty:ty) => { ... };
    ($name:ident, $operator:expr, $return_ty:ty, backend: $backend:ty) => { ... };
}

Useful for libraries adding support for new SQL types. Apps should never need to call this.

Similar to infix_operator!, but the generated type will only take a single argument rather than two. The operator SQL will be placed before the single argument. See infix_operator! for example usage.