require.h

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#pragma once
#include <derive-c/core/namespace.h>
#include <derive-c/core/compiler.h>
 
#if defined DC_GENERIC_KEYWORD_SUPPORTED
    #define DC_REQUIRE_FUNCTION(ret, func, args) _Generic(func, ret(*) args: 1, default: 0)
    #define DC_REQUIRE_CONSTANT_TYPE_EXPR(obj, name, Type)                                         \
        _Generic((NS(obj, name)), Type: 1, default: 0)
#else
    #include <type_traits> // NOLINT(misc-include-cleaner)
    #define DC_REQUIRE_FUNCTION(ret, func, args) std::is_same_v<decltype(+func), ret(*) args>
    #define DC_REQUIRE_CONSTANT_TYPE_EXPR(obj, name, Type)                                         \
        std::is_same_v<std::remove_cv_t<std::remove_reference_t<decltype(NS(obj, name))>>, Type>
#endif
 
#define DC_REQUIRE_METHOD(ret, obj, name, args)                                                    \
    DC_STATIC_ASSERT(DC_REQUIRE_FUNCTION(ret, NS(obj, name), args),                                \
                     "Method " #obj "." #name " must exist with type " #ret " (*)" #args)
 
// JUSTIFY: +1 on sizeof
//  - We use the sizeof to enforce the type exists
//  - For zero sized types, we need the expression to not be zero.
#define DC_REQUIRE_TYPE(obj, name) DC_STATIC_ASSERT(sizeof(NS(obj, name)) + 1)
 
#define DC_REQUIRE_CONSTANT(obj, name, type)                                                       \
    DC_STATIC_ASSERT(DC_REQUIRE_CONSTANT_TYPE_EXPR(obj, name, type),                               \
                     "Method " #obj "." #name " must exist and be of type " #type)