diff options
Diffstat (limited to 'libobj/include')
| -rw-r--r-- | libobj/include/libobj/obj.h | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/libobj/include/libobj/obj.h b/libobj/include/libobj/obj.h new file mode 100644 index 0000000..d8a528a --- /dev/null +++ b/libobj/include/libobj/obj.h @@ -0,0 +1,154 @@ +/* libobj/obj.h - A simple Go-ish object system + * + * Copyright (C) 2024-2025 Luke T. Shumaker <lukeshu@lukeshu.com> + * SPDX-License-Identifier: AGPL-3.0-or-later + */ + +#ifndef _LIBOBJ_OBJ_H_ +#define _LIBOBJ_OBJ_H_ + +#include <libmisc/macro.h> + +/** + * Use `lo_interface` similarly to how you would use + * `struct`/`enum`/`union` when writing the type of an interface + * value. + */ +#define lo_interface struct + +/** + * Use `LO_INTERFACE` in a .h file to define an interface. + * + * First define a macro named `{iface_name}_LO_IFACE` consisting of a + * series of calls to LO_NEST and/or LO_FUNC, then call + * `LO_INTERFACE({iface_name})`: + * + * #define myiface_LO_IFACE \ + * LO_NEST(wrapped_iface_name) \ + * LO_FUNC(ret_type, func_name, args...) + * LO_INTERFACE(myiface) + * + * Use `lo_interface {iface_name}` as the type of this interface; it + * should not be a pointer type. + * + * If there are any LO_NEST interfaces, this will define a + * `lo_box_{iface_name}_as_{wrapped_iface_name}(obj)` function for + * each. + */ +#define LO_NEST(_ARG_child_iface_name) \ + (lo_nest, _ARG_child_iface_name) +#define LO_FUNC(_ARG_ret_type, _ARG_func_name, ...) \ + (lo_func, _ARG_ret_type, _ARG_func_name __VA_OPT__(,) __VA_ARGS__) +#define LO_INTERFACE(_ARG_iface_name) \ + typedef struct { \ + LM_FOREACH_TUPLE(_ARG_iface_name##_LO_IFACE, \ + _LO_IFACE_VTABLE) \ + } _lo_##_ARG_iface_name##_vtable; \ + struct _ARG_iface_name { \ + void *self; \ + const _lo_##_ARG_iface_name##_vtable *vtable; \ + }; \ + LM_FOREACH_TUPLE(_ARG_iface_name##_LO_IFACE, \ + _LO_IFACE_PROTO, _ARG_iface_name) +#define _LO_IFACE_VTABLE(_tuple_typ, ...) \ + _LO_IFACE_VTABLE_##_tuple_typ(__VA_ARGS__) +#define _LO_IFACE_VTABLE_lo_nest(_ARG_child_iface_name) \ + _lo_##_ARG_child_iface_name##_vtable; +#define _LO_IFACE_VTABLE_lo_func(_ARG_ret_type, _ARG_func_name, ...) \ + _ARG_ret_type (*_ARG_func_name)(void * __VA_OPT__(,) __VA_ARGS__); +#define _LO_IFACE_PROTO(_ARG_iface_name, _tuple_typ, ...) \ + _LO_IFACE_PROTO_##_tuple_typ(_ARG_iface_name, __VA_ARGS__) +#define _LO_IFACE_PROTO_lo_nest(_ARG_iface_name, _ARG_child_iface_name) \ + LM_ALWAYS_INLINE static lo_interface _ARG_child_iface_name \ + box_##_ARG_iface_name##_as_##_ARG_child_iface_name(lo_interface _ARG_iface_name obj) { \ + return (lo_interface _ARG_child_iface_name){ \ + .self = obj.self, \ + .vtable = &obj.vtable->_lo_##_ARG_child_iface_name##_vtable, \ + }; \ + } +#define _LO_IFACE_PROTO_lo_func(_ARG_iface_name, _ARG_ret_type, _ARG_func_name, ...) \ + /* empty */ + +/** + * `LO_NULL(iface_name)` is the null/nil/zero value for `lo_interface {iface_name}`. + */ +#define LO_NULL(_ARG_iface_name) ((lo_interface _ARG_iface_name){0}) + +/** + * `LO_IS_NULL(iface_val)` returns whether `iface_val` is LO_NULL. + */ +#define LO_IS_NULL(_ARG_iface_val) ((_ARG_iface_val).vtable == NULL) + +/** + * `LO_IFACE_EQ(a, b)` returns whether the interface values `a` and + * `b` are the same object. + */ +#define LO_EQ(_ARG_iface_val_a, _ARG_iface_val_b) \ + ((_ARG_iface_val_a).self == (_ARG_iface_val_b).self) + +/** + * Use LO_CALL(obj, method_name, args...) to call a method on an `lo_interface`. + */ +#define LO_CALL(_ARG_obj, _ARG_meth, ...) \ + (_ARG_obj).vtable->_ARG_meth((_ARG_obj).self __VA_OPT__(,) __VA_ARGS__) + +/** + * Use `LO_IMPLEMENTATION_H(iface_name, impl_type, impl_name)` in a .h + * file to declare that `{impl_type}` implements the `{iface_name}` + * interface with functions named `{impl_name}_{method_name}`. + * + * This will also define a `lo_box_{impl_name}_as_{iface_name}(obj)` + * function. + * + * You must also call the LO_IMPLEMENTATION_C in a single .c file. + */ +#define LO_IMPLEMENTATION_H(_ARG_iface_name, _ARG_impl_type, _ARG_impl_name) \ + /* Vtable. */ \ + extern const _lo_##_ARG_iface_name##_vtable \ + _lo_##_ARG_impl_name##_##_ARG_iface_name##_vtable; \ + /* Boxing. */ \ + LM_ALWAYS_INLINE static lo_interface _ARG_iface_name \ + lo_box_##_ARG_impl_name##_as_##_ARG_iface_name(_ARG_impl_type *self) { \ + return (lo_interface _ARG_iface_name){ \ + .self = self, \ + .vtable = &_lo_##_ARG_impl_name##_##_ARG_iface_name##_vtable, \ + }; \ + } + +/** + * Use `LO_IMPLEMENTATION_C(iface_name, impl_type, impl_name[, static])` in a .c + * file to declare that `{impl_type}` implements the `{iface_name}` interface + * with functions named `{impl_name}_{method_name}`. + * + * You must also call the LO_IMPLEMENTATION_H in the corresponding .h file. + * + * If `iface_name` contains a nested interface, then the + * implementation of the nested interfaces must be declared with + * `LO_IMPLEMENTATION_C` first. + */ +#define LO_IMPLEMENTATION_C(_ARG_iface_name, _ARG_impl_type, _ARG_impl_name, ...) \ + /* Method prototypes. */ \ + LM_FOREACH_TUPLE(_ARG_iface_name##_LO_IFACE, \ + _LO_IMPL_PROTO, _ARG_impl_type, _ARG_impl_name, __VA_ARGS__) \ + /* Vtable. */ \ + const _lo_##_ARG_iface_name##_vtable \ + _lo_##_ARG_impl_name##_##_ARG_iface_name##_vtable = { \ + LM_FOREACH_TUPLE(_ARG_iface_name##_LO_IFACE, \ + _LO_IMPL_VTABLE, _ARG_impl_name) \ + }; \ + +#define _LO_IMPL_PROTO(_ARG_impl_type, _ARG_impl_name, _ARG_quals, _tuple_typ, ...) \ + _LO_IMPL_PROTO_##_tuple_typ(_ARG_impl_type, _ARG_impl_name, _ARG_quals, __VA_ARGS__) +#define _LO_IMPL_PROTO_lo_nest(_ARG_impl_type, _ARG_impl_name, _ARG_quals, _ARG_child_iface_name) \ + /* empty */ +#define _LO_IMPL_PROTO_lo_func(_ARG_impl_type, _ARG_impl_name, _ARG_quals, _ARG_ret_type, _ARG_func_name, ...) \ + _ARG_quals _ARG_ret_type _ARG_impl_name##_##_ARG_func_name(_ARG_impl_type * __VA_OPT__(,) __VA_ARGS__); + +#define _LO_IMPL_VTABLE(_ARG_impl_name, _tuple_typ, ...) \ + _LO_IMPL_VTABLE_##_tuple_typ(_ARG_impl_name, __VA_ARGS__) +#define _LO_IMPL_VTABLE_lo_nest(_ARG_impl_name, _ARG_child_iface_name) \ + ._lo_##_ARG_child_iface_name##_vtable = _lo_##_ARG_impl_name##_##_ARG_child_iface_name##_vtable, +#define _LO_IMPL_VTABLE_lo_func(_ARG_impl_name, _ARG_ret_type, _ARG_func_name, ...) \ + ._ARG_func_name = (void*)_ARG_impl_name##_##_ARG_func_name, + +#endif /* _LIBOBJ_OBJ_H_ */ |