What's the use of 'typeof','typeid','__traits','is' ?

[David T. Oxygen]

On Sunday, 24 August 2025 at 03:29:30 UTC, Paul Backus wrote:
> On Sunday, 24 August 2025 at 03:13:38 UTC, David T. Oxygen 
> wrote:
>> Hello every kind and helpful D programmers, I need your help.
>>
>> I've met two problems about getting types.
>> In D, we can use many keywords to get the type of an object, 
>> such as `typeof`,`typeid`,`is`.
>> However, I don't know the differences between them well. I 
>> also don't know how to use them in D...
>
> `typeof` is evaluated at compile time and gives the type of an 
> expression or symbol as seen by the compiler.
>
> `typeid` is evaluated at runtime and gives the [`TypeInfo`][1] 
> object containing information about an object's runtime type.
>
> [1]: https://dlang.org/library/object/type_info.html
>

--
Thanks.
But I still don't know how to use `is` `__traits`.
And, how can I fill in `/*?????*/`? Can I use 
`typeid(result)==MyInt`? Or if the `is` keyword can do this?