virtuals.hpp File Reference

welder's backend-neutral virtual-slot machinery: which virtual member functions of a type are overridable from the target language, and the bind_flat opt-out marker. More...

#include <cstddef>
#include <meta>
#include <string_view>
#include <vector>
#include <welder/diag.hpp>

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Classes
struct	welder::bind_flat_spec
	The stored form of a bind_flat mark (a plain tag — it carries no state). More...

Namespaces
namespace	welder
namespace	welder::detail
	The stored forms of the annotation vocabulary.

Functions
consteval bool	welder::bound_flat (std::meta::info entity)
	Does entity (a type or a member function) carry a bind_flat mark?
consteval bool	welder::is_overridable_virtual (std::meta::info member)
	Is member an overridable virtual — a virtual member function that welder routes through the trampoline?
consteval bool	welder::detail::same_slot (std::meta::info a, std::meta::info b)
	Do a and b declare the same vtable slot?
consteval void	welder::detail::collect_virtuals (std::meta::info type, std::vector< std::meta::info > &slots)
	Accumulate the most-derived declaration of every virtual member function reachable in type's complete object into slots, deduplicating by vtable slot (same_slot — name + parameters + cv/ref, so a covariant override is one slot, not two).
consteval std::vector< std::meta::info >	welder::overridable_virtuals (std::meta::info type)
	Every overridable virtual slot of type — the ones welder routes through a trampoline — folding in virtuals inherited from any base.
consteval std::meta::info	welder::virtual_slot (std::meta::info type, std::string_view name, std::meta::info fn_type)
	The overridable virtual slot of type named name whose function type is fn_type — the hand-written disambiguator for an overloaded virtual.
consteval std::size_t	welder::virtual_slot_count (std::meta::info type)
	The number of overridable virtual member functions of type, inherited ones included.
consteval bool	welder::has_virtual_methods (std::meta::info type)
	Does type declare or inherit any overridable virtual method?

Variables
constexpr bind_flat_spec	welder::bind_flat {}
	Mark a virtual entity as deliberately bound non-overridably.

Detailed Description

welder's backend-neutral virtual-slot machinery: which virtual member functions of a type are overridable from the target language, and the bind_flat opt-out marker.

Very different backends consume the same answers: the Python rods route these slots through hand-authored trampolines (the authoring macros and the trampoline registration live in <welder/rods/python/trampoline.hpp>, which re-exports everything here under its historical welder::rods::python spellings), while out-of-tree rods can generate e.g. director subclasses over the identical slot set. Keeping the slot semantics in one place is what makes "overridable" mean the same thing in every language: vtable-slot identity (covariant overrides fold to one slot), inherited virtuals folded in, protected NVI hooks included, private declarations withdrawing their slot, and bind_flat opting a type or method out.

Like the rest of the reflection layer this is header-only, std-<meta> based, and free of any framework dependency.

Definition in file virtuals.hpp.