Type resolution for std.builtin.Type.StructField

[Sze]

You can do something like this:

@Sze

pub const ComptimeAny = struct {
    type: type,
    ptr: *const anyopaque,

    pub fn init(comptime val: anytype) ComptimeAny {
        return .{ .type = @TypeOf(val), .ptr = @ptrCast(&val) };
    }

    pub fn value(self: ComptimeAny) self.type {
        const val: *const self.type = @ptrCast(@alignCast(self.ptr));
        return val.*;
    }

    pub fn format(
        self: ComptimeAny,
        writer: *std.Io.Writer,
    ) std.Io.Writer.Error!void {
        if (comptime hasDecl(self.type, "format")) {
            try writer.print("{f}", .{self.value()});
        } else {
            try writer.print("{any}", .{self.value()});
        }
    }
};

This post is also somewhat related and interesting How to construct a tuple at compile time using a for loop? - #5 by mlugg

Whether you should use these possibilities is another question…