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use crate::{Error, Result}; use proc_macro2::{Ident, Span, TokenStream, TokenTree}; macro_rules! decl_settings { ($($val:expr => $variant:ident),+ $(,)*) => { #[derive(PartialEq)] pub(crate) enum Setting { $($variant),* } fn ident_to_setting(ident: Ident) -> Result<Setting> { match &*ident.to_string() { $($val => Ok(Setting::$variant),)* _ => { let possible_vals = [$($val),*] .iter() .map(|v| format!("`{}`", v)) .collect::<Vec<_>>() .join(", "); Err(Error::new( ident.span(), format!("unknown setting `{}`, expected one of {}", ident, possible_vals))) } } } }; } decl_settings! { "assert_unwind_safe" => AssertUnwindSafe, "allow_not_macro" => AllowNotMacro, "proc_macro_hack" => ProcMacroHack, } pub(crate) fn parse_settings(input: TokenStream) -> Result<Settings> { let mut input = input.into_iter(); let mut res = Settings(Vec::new()); loop { match input.next() { Some(TokenTree::Ident(ident)) => { res.0.push(ident_to_setting(ident)?); } None => return Ok(res), other => { let span = other.map_or(Span::call_site(), |tt| tt.span()); return Err(Error::new(span, "expected identifier".to_string())); } } match input.next() { Some(TokenTree::Punct(ref punct)) if punct.as_char() == ',' => {} None => return Ok(res), other => { let span = other.map_or(Span::call_site(), |tt| tt.span()); return Err(Error::new(span, "expected `,`".to_string())); } } } } pub(crate) struct Settings(Vec<Setting>); impl Settings { pub(crate) fn is_set(&self, setting: Setting) -> bool { self.0.iter().any(|s| *s == setting) } pub(crate) fn set(&mut self, setting: Setting) { self.0.push(setting) } }