Macro storage 

macro_rules! storage {
    ($t:ty) => { ... };
    ($t:ty, $u:ty) => { ... };
    ($t:ty, $n:expr) => { ... };
    ($t:ty, $u:ty, $n:expr) => { ... };
}

Declare packrat storage

Arguments

• An output type of parser. The type must implement Clone.
• (Optional) An extra key type. The type must implement Eq + Hash + Clone.
• (Optional) Maximum entries of storage.

Examples

storage!(String);
storage!(String, 1024);
storage!(String, ExtraInfo);
storage!(String, ExtraInfo, 1024);