[Web Feed] Recently I???ve been working on a project to surface census data via a GraphQL ...

..API, mostly as a way to learn GraphQL. I did end up learning 



Recently I’ve been working on a project to surface census data via a GraphQL API, mostly as a way to learn GraphQL. I did end up learning GraphQL, but I also ended up learning a lot about proc macros. I was using Juniper, which creates a GraphQL schema using structs like this:



#[derive(GraphQLObject, Copy, Clone, Debug)]
struct Demographics {
    female: Option<i32>,
    male: Option<i32>,
}



The problem, is that the census data I was looking to surface had _way_ too many variables, I would have had to write out 207 structs, with a total of 352 fields. Here’s a 
gist.github.com/marcusbuffett/693026a0a8923bec98e67259f5e71a66: nice tree-view of the census data, courtesy of the 
github.com/birchb1024/frangipanni: frangipanni tool. Obviously, I didn’t want to write out all these structs and fields by hand, even with some fancy vim macros that would have been too much tedious work for a side project that’s supposed to be fun.

I dipped my toes into proc macros for the first time, and found they really weren’t that hard, but the resources out there are so scarce. All I wanted was a few examples of non-trivial macros, but I couldn’t find many. So this isn’t a full proc macros walkthrough, just a quick look at the macro I ended up writing for my use case.




Link 1


    
    An Incomplete Explanation of the Proc Macro That Saved Me 4000 Lines of Rust :: A blog  — Just a blog
    
: https://mbuffett.com/posts/incomplete-macro-walkthrough