boring-derive 0.1.1

Derive macros for some common patterns
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51

use std::{cell::RefCell, fmt::Display, thread};

use quote::ToTokens;

#[derive(Default)]
pub struct Context {
    pub errors: RefCell<Option<Vec<syn::Error>>>,
}

impl Context {
    pub fn new() -> Self {
        Context {
            errors: RefCell::new(Some(Vec::new())),
        }
    }

    pub fn error_spanned_by<A: ToTokens, T: Display>(&self, obj: A, msg: T) {
        self.errors
            .borrow_mut()
            .as_mut()
            .unwrap()
            .push(syn::Error::new_spanned(obj.into_token_stream(), msg));
    }

    pub fn syn_error(&self, err: syn::Error) {
        self.errors.borrow_mut().as_mut().unwrap().push(err);
    }

    pub fn check(self) -> syn::Result<()> {
        let mut errors = self.errors.borrow_mut().take().unwrap().into_iter();

        let mut combined = match errors.next() {
            Some(first) => first,
            None => return Ok(()),
        };

        for rest in errors {
            combined.combine(rest)
        }

        Err(combined)
    }
}

impl Drop for Context {
    fn drop(&mut self) {
        if !thread::panicking() && self.errors.borrow().is_some() {
            panic!("forgot to check for errors");
        }
    }
}