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//! Macros helpers in genco. /// Macro to implement support for a custom language. /// /// # Examples /// /// ```rust /// use genco::fmt; /// use std::fmt::Write as _; /// /// #[derive(Default)] /// struct Config { /// } /// /// #[derive(Default)] /// struct Format { /// } /// /// genco::impl_lang! { /// MyLang { /// type Config = Config; /// type Import = dyn AsAny; /// type Format = Format; /// /// fn write_quoted(out: &mut fmt::Formatter<'_>, input: &str) -> fmt::Result { /// genco::lang::c_family_write_quoted(out, input) /// } /// /// fn format_file( /// tokens: &Tokens<MyLang>, /// out: &mut fmt::Formatter<'_>, /// config: &Self::Config, /// ) -> fmt::Result { /// use genco::quote_in; /// /// let mut header: Tokens<MyLang> = Tokens::new(); /// let mut any_imports = false; /// /// for import in tokens.walk_imports() { /// any_imports = true; /// /// match import.as_any() { /// Any::Import(import) => { /// header.push(); /// quote_in!(header => import #(import.0)); /// } /// Any::ImportDefault(import) => { /// header.push(); /// quote_in!(header => import default #(import.0)); /// } /// } /// } /// /// if any_imports { /// // Add a line as padding in case we have any imports. /// header.line(); /// } /// /// let format = Format::default(); /// header.format(out, config, &format)?; /// tokens.format(out, config, &format)?; /// Ok(()) /// } /// } /// /// Import { /// fn format(&self, out: &mut fmt::Formatter<'_>, config: &Config, _: &Format) -> fmt::Result { /// out.write_str(self.0)?; /// Ok(()) /// } /// /// fn as_import(&self) -> Option<&dyn AsAny> { /// Some(self) /// } /// } /// /// ImportDefault { /// fn format(&self, out: &mut fmt::Formatter<'_>, config: &Config, _: &Format) -> fmt::Result { /// write!(out, "default:{}", self.0)?; /// Ok(()) /// } /// /// fn as_import(&self) -> Option<&dyn AsAny> { /// Some(self) /// } /// } /// } /// /// #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] /// struct Import(&'static str); /// /// #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] /// struct ImportDefault(&'static str); /// /// use genco::{quote, Tokens}; /// /// # fn main() -> genco::fmt::Result { /// let a = Import("first"); /// let b = ImportDefault("second"); /// /// let t: Tokens<MyLang> = quote! { /// #a /// #b /// }; /// /// assert_eq! { /// vec![ /// "import first", /// "import default second", /// "", /// "first", /// "default:second" /// ], /// t.to_file_vec()? /// }; /// # Ok(()) /// # } /// ``` #[macro_export] macro_rules! impl_lang { ( $(#[$($meta:meta)*])* $vis:vis $lang:ident { $($lang_item:tt)* } $( $ty:ident { $($ty_lang_item_item:tt)* } )* ) => { $(#[$($meta)*])* $vis struct $lang(()); impl $crate::lang::Lang for $lang { $($lang_item)* } /// Language-specific conversion trait implemented by all language /// items. $vis trait AsAny: $crate::lang::LangItem<$lang> { /// Coerce trait into an enum that can be used for type-specific /// operations. /// /// # Examples /// /// ```rust /// genco::impl_lang! { /// MyLang { /// type Config = (); /// type Import = dyn AsAny; /// type Format = (); /// } /// /// Import { /// fn as_import(&self) -> Option<&dyn AsAny> { /// Some(self) /// } /// } /// }; /// /// #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] /// struct Import(usize); /// /// use genco::{quote, Tokens}; /// /// let t: Tokens<MyLang> = quote! { /// #(Import(0)) /// #(Import(1)) /// }; /// /// /// Find and compare all imports. /// assert_eq!(2, t.walk_imports().count()); /// /// for (i, import) in t.walk_imports().enumerate() { /// assert_eq!(Any::Import(&Import(i)), import.as_any()); /// } /// ``` fn as_any(&self) -> Any<'_>; } /// Enum produced by [AsAny::as_any()] which can be used to identify and /// operate over a discrete language item type. #[derive(Debug, Hash, PartialEq, Eq, PartialOrd, Ord)] $vis enum Any<'a> { $( #[doc = "Type variant."] $ty(&'a $ty), )* } $( impl AsAny for $ty { fn as_any(&self) -> Any<'_> { Any::$ty(self) } } impl $crate::tokens::FormatInto<$lang> for $ty { fn format_into(self, tokens: &mut $crate::Tokens<$lang>) { let b = $crate::lang::LangBox::new(self); tokens.item($crate::tokens::Item::LangBox(b)); } } impl<'a> $crate::tokens::FormatInto<$lang> for &'a $ty { fn format_into(self, tokens: &mut $crate::Tokens<$lang>) { let b = $crate::lang::LangBox::new(self.clone()); tokens.item($crate::tokens::Item::LangBox(b)); } } impl $crate::tokens::Register<$lang> for $ty { fn register(self, tokens: &mut $crate::Tokens<$lang>) { let b = $crate::lang::LangBox::new(self); tokens.item($crate::tokens::Item::Registered(b)); } } impl<'a> $crate::tokens::Register<$lang> for &'a $ty { fn register(self, tokens: &mut $crate::Tokens<$lang>) { let b = $crate::lang::LangBox::new(self.clone()); tokens.item($crate::tokens::Item::Registered(b)); } } impl $crate::lang::LangItem<$lang> for $ty { $($ty_lang_item_item)* fn __lang_item_as_any(&self) -> &dyn std::any::Any { self } fn __lang_item_clone(&self) -> Box<dyn $crate::lang::LangItem<$lang>> { Box::new(self.clone()) } fn __lang_item_eq(&self, other: &dyn $crate::lang::LangItem<$lang>) -> bool { other .__lang_item_as_any() .downcast_ref::<Self>() .map_or(false, |x| x == self) } } )* } }