Re: Reusing parts of the AST in macros

[xomachine]

@Ivan not sure that I understand it properly, but I think you may save AST 
parts you need in the global variables while code generation, like I did in my 
[de]serializer: 
[declaration](https://github.com/xomachine/NESM/blob/master/nesm.nim#L273) 
[usage](https://github.com/xomachine/NESM/blob/master/nesm.nim#L380) In my case 
it is being used for a bit different purpose: saving serialization 
implementation for nested types, but I hope you will find something useful in 
this concept.