Macro opg::describe_type

macro_rules! describe_type {
    (raw_model => $model : ident) => { ... };
    (raw_type =>
 { $(description : $description : literal) ? ident : $type : ident }) => { ... };
    (string =>
 {
     $(description : $description : literal) ? $(format : $format : literal) ?
     $(example : $example : literal) ?
     $(variants : [$($variants : literal), *]) ?
 }) => { ... };
    (number =>
 {
     $(description : $description : literal) ? $(format : $format : literal) ?
     $(example : $example : literal) ?
 }) => { ... };
    (integer =>
 {
     $(description : $description : literal) ? $(format : $format : literal) ?
     $(example : $example : literal) ?
 }) => { ... };
    (boolean => { $(description : $description : literal) ? }) => { ... };
    (array =>
 {
     $(description : $description : literal) ? items :
     ($($property_tail : tt) *)
 }) => { ... };
    (object =>
 {
     $(description : $description : literal) ? properties :
     {
         $($property_name : ident $([$required : tt]) ? :
           ($($property_tail : tt) *)) *
     }
 }) => { ... };
    (@ object_property [$properties : ident, $required : ident] $property_name :
 ident : ($($property_tail : tt) *)) => { ... };
    (@ object_property [$properties : ident, $required : ident] $property_name :
 ident [required] : ($($property_tail : tt) *)) => { ... };
    (@ object_property_value link => $ref : literal) => { ... };
    (@ object_property_value link => $ref : ident) => { ... };
    (@ object_property_value $type : ident => $($tail : tt) *) => { ... };
}