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const std = @import("std");
fn A(comptime T: type) type {
const ti = @typeInfo(T).@"struct";
var names: [ti.fields.len + ti.decls.len][]const u8 = undefined;
var types: [ti.fields.len + ti.decls.len]type = undefined;
var attrs: [ti.fields.len + ti.decls.len]std.builtin.Type.StructField.Attributes = undefined;
inline for (ti.fields, 0..) |field, idx| {
names[idx] = field.name;
types[idx] = extern struct {
value: field.type,
pub fn get(self: @This()) field.type {
std.debug.print("getting {s}\n", .{field.name});
return self.value;
}
pub fn set(self: @This(), value: field.type) void {
std.debug.print("setting {s}\n", .{field.name});
self.value = value;
}
};
const default = if (field.default_value_ptr) |def| types[idx] {.value = @as(*field.type, @constCast(@ptrCast(@alignCast(def)))).*} else null;
attrs[idx] = .{
.@"comptime" = field.is_comptime,
.@"align" = field.alignment,
.default_value_ptr = &default,
};
}
inline for (ti.decls, 0..) |decl, idx| {
const default = struct {
pub fn call() void {
std.debug.print("calling {s}\n", .{decl.name});
@call(.auto, @field(T, decl.name), .{});
std.debug.print("done calling {s}\n", .{decl.name});
}
};
names[ti.fields.len + idx] = decl.name;
types[ti.fields.len + idx] = type;
attrs[ti.fields.len + idx] = .{.default_value_ptr = &default};
}
return @Struct(.auto, null, &names, &types, &attrs);
}
pub fn main() !void {
const a = A(struct {
i: i32 = 123,
j: i32 = 456,
pub fn b() void {
std.debug.print("B!\n", .{});
}
pub fn c() void {
std.debug.print("C!\n", .{});
}
}) {};
std.debug.print("[{}] {}\n", .{@TypeOf(a), a});
a.b.call();
a.c.call();
std.debug.print("{}\n", .{a.i.get()});
std.debug.print("{}\n", .{a.j.get()});
}
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