Macro combu::default_val

macro_rules! default_val {
    (description$(.$ident:ident)+) => { ... };
    (name$(.$ident:ident)+) => { ... };
    (flag.$ident:ident.alias.short) => { ... };
    ($ident:ident.flag.alias.short) => { ... };
    (flag.$ident:ident.short.alias) => { ... };
    ($ident:ident.flag.short.alias) => { ... };
    (flag.$ident:ident.short_alias) => { ... };
    ($ident:ident.flag.short_alias) => { ... };
    ($ident:ident$(.$ident2:ident)+) => { ... };
    ([$($ident:ident).+].description) => { ... };
    ([$($ident:ident).+].name) => { ... };
    ([$($ident:ident).+].$ident2:ident$(.$ident3:ident)*) => { ... };
}

Default value for presets.