1use std::borrow::Cow;
2
3use defmt_parser::Level;
4use proc_macro::TokenStream;
5use quote::quote;
6use syn::parse_macro_input;
7
8use crate::{construct, function_like::log};
9
10pub(crate) fn expand(
11 args: TokenStream,
12 zero_args_format_string: &str,
13 transform_format_string: impl FnOnce(&str) -> String,
14) -> TokenStream {
15 let (format_string, formatting_args) = if args.is_empty() {
16 // panic!() -> error!("panicked at 'explicit panic'")
17 (Cow::from(zero_args_format_string), None)
18 } else {
19 // panic!("a", b, c) -> error!("panicked at 'a'", b, c)
20 let log_args = parse_macro_input!(args as log::Args);
21 let format_string = transform_format_string(&log_args.format_string.value());
22
23 (Cow::from(format_string), log_args.formatting_args)
24 };
25
26 let format_string = construct::string_literal(&format_string);
27 let log_stmt = log::expand_parsed(
28 Level::Error,
29 log::Args {
30 format_string,
31 formatting_args,
32 },
33 );
34
35 quote!(
36 {
37 #log_stmt;
38 defmt::export::panic()
39 }
40 )
41 .into()
42}
43