Visit a polymorphic object by matching its kind to a derived type.
Declared in <mrdocs/Support/TypeTraits/Visitor.hpp>
template<
class Info,
class Fn,
class... Args>
requires (describe::has_describe_kinds<std::remove_cvref_t<Info>>::value
|| requires { std::remove_cvref_t<Info>::kind_id; })
decltype(auto)
visit(
Info& info,
Fn&& fn,
Args&&... args);Accepts either a polymorphic base registered with MRDOCS_DESCRIBE_KINDS, or one of its concrete kinds (a type carrying a kind_id).
Given a base, it reads the concrete kinds from describe::describe_kinds and calls fn with the object downcast to the kind whose kind_id equals info.Kind, followed by args.
Given a concrete kind, the type is already known statically, so there is nothing to dispatch: fn is called with info directly. This lets a caller that already holds a concrete node (e.g. the global NamespaceSymbol) pass it without casting to the base first.
The result of calling fn with the concrete object.
| Name | Description |
|---|---|
| info | The object to visit; when it is a base, info.Kind selects the derived type. |
| fn | The function called with the concrete object and args. |
| args | Extra arguments forwarded to fn. |