Add macros for include ttrpc gen code

[jokemanfire]

Give macros for more convenient to use, if it is in Default dir

[Tim-Zhang]

Then how to include helloworld.rs?

[jokemanfire]

What I think is that this macro only provides the code for *_ttrpc.rs generated by ttrpc-code gen The generated proto's rs code is not within the scope of this macro.

[Tim-Zhang]

@jokemanfire I have a question, how useful is the development of these API? After all, the more open the API is, the more disadvantageous it is for us to maintain compatibility.

[jokemanfire]

@jokemanfire I have a question, how useful is the development of these API? After all, the more open the API is, the more disadvantageous it is for us to maintain compatibility.

What I add is for the interface , "include!(concat!(env!("OUT_DIR"), "/mod.rs"));" is ugly , and is not friendly to caller. In tonic they provide a marco which I think it is useful and more friendly https://github.com/hyperium/tonic/blob/5ad89bf5c2ec651afca73f946fff3ae5b996481c/tonic/src/macros.rs . So i add it.
And I think this interface should be controllable for developers because it is relatively simple in itself.

[Tim-Zhang]

@jokemanfire I have a question, how useful is the development of these API? After all, the more open the API is, the more disadvantageous it is for us to maintain compatibility.

The sentence include!(concat!(env!("OUT_DIR"), "/mod.rs")) is internal and appear only once. So do we really need the macro include_mod?

The macro include_ttrpc is not general for it only works for *_ttrpc.rs in OUT_DIR.

Still I don't think we need these two macros. welcome to discuss, thanks.

[jokemanfire]

@jokemanfire I have a question, how useful is the development of these API? After all, the more open the API is, the more disadvantageous it is for us to maintain compatibility.

The sentence include!(concat!(env!("OUT_DIR"), "/mod.rs")) is internal and appear only once. So do we really need the macro include_mod?

The macro include_ttrpc is not general for it only works for *_ttrpc.rs in OUT_DIR.

Still I don't think we need these two macros. welcome to discuss, thanks.

At that time, adding two interfaces was for the convenience of one of my projects, May be we can use

macro_rules! include_ttrpc {
    ($name:expr) => {
        include!(concat!(env!("OUT_DIR"), concat!("/", $name, ".rs")));
    };
}

If it is more greater?

[jokemanfire]

This scenario is that I do not want to keep the code generated by codegen, and developers do not need to pay attention to the code generated by ttrpc codegen. At this point, the code is generated in the directory of the OUT_SIR environment variable. Then I want to reference this * _ttrpc.rs code. I have to include a rather ugly code
include!(concat!(env!("OUT_DIR"), "/mod.rs"))
(Newcomers who have just started reading the document know that they need to use include to include it). If this macro is provided, the caller will be more happy to include this file (at least it doesn't look so ugly, at least to me)

[Tim-Zhang]

Firstly, The output dir of generated code may not in env!("OUT_DIR").
Secondly in my opinion include generated files is the job of users, we'd better leave it alone.

Any suggests? @lifupan @teawater