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#![recursion_limit = "128"] extern crate proc_macro; use crate::proc_macro::TokenStream; use quote::quote; use syn::Data::{Enum, Struct}; use syn::{self, DeriveInput}; #[proc_macro_derive(Node)] pub fn node_derive(input: TokenStream) -> TokenStream { let ast = syn::parse(input).unwrap(); impl_node(&ast) } fn impl_node(ast: &DeriveInput) -> TokenStream { let name = &ast.ident; let next = match ast.data { Enum(ref data) => { let mut items = quote! {}; for v in &data.variants { let ident = &v.ident; let item = quote! { #name::#ident(x) => { x.into() }, }; items = quote! { #items #item }; } quote! { match self { #items } } } Struct(_) => { quote! { (&(self.nodes)).into() } } _ => { quote! { vec![].into() } } }; let gen = quote! { impl<'a> Node<'a> for #name { fn next(&'a self) -> RefNodes<'a> { #next } } impl<'a> From<&'a #name> for RefNodes<'a> { fn from(x: &'a #name) -> Self { vec![RefNode::#name(x)].into() } } impl From<#name> for AnyNode { fn from(x: #name) -> Self { AnyNode::#name(x) } } impl<'a> From<&'a #name> for RefNode<'a> { fn from(x: &'a #name) -> Self { RefNode::#name(x) } } impl core::convert::TryFrom<#name> for Locate { type Error = (); fn try_from(x: #name) -> Result<Self, Self::Error> { Self::try_from(&x) } } impl<'a> core::convert::TryFrom<&'a #name> for Locate { type Error = (); fn try_from(x: &'a #name) -> Result<Self, Self::Error> { let mut locate: Option<Locate> = None; for x in x { match x { RefNode::Locate(x) => if let Some(loc) = locate { assert_eq!(x.offset, loc.offset + loc.len); locate = Some(Locate { offset: loc.offset, line: loc.line, len: loc.len + x.len }); } else { locate = Some(*x); }, _ => (), } } locate.ok_or(()) } } impl<'a> IntoIterator for &'a #name { type Item = RefNode<'a>; type IntoIter = Iter<'a>; fn into_iter(self) -> Self::IntoIter { let mut nodes: RefNodes = self.into(); nodes.0.reverse(); Iter { next: nodes } } } }; gen.into() } #[proc_macro_derive(AnyNode)] pub fn any_node_derive(input: TokenStream) -> TokenStream { let ast = syn::parse(input).unwrap(); impl_any_node(&ast) } fn impl_any_node(ast: &DeriveInput) -> TokenStream { let ref data = match ast.data { Enum(ref data) => data, _ => unreachable!(), }; let mut try_froms = quote! {}; let mut from_items = quote! {}; for v in &data.variants { let ident = &v.ident; try_froms = quote! { #try_froms impl TryFrom<AnyNode> for #ident { type Error = (); fn try_from(x: AnyNode) -> Result<Self, Self::Error> { match x { AnyNode::#ident(x) => Ok(x), _ => Err(()), } } } }; from_items = quote! { #from_items AnyNode::#ident(x) => RefNode::#ident(&x), }; } let gen = quote! { #try_froms impl<'a> From<&'a AnyNode> for RefNode<'a> { fn from(x: &'a AnyNode) -> Self { match x { #from_items } } } }; gen.into() } #[proc_macro_derive(RefNode)] pub fn ref_node_derive(input: TokenStream) -> TokenStream { let ast = syn::parse(input).unwrap(); impl_ref_node(&ast) } fn impl_ref_node(ast: &DeriveInput) -> TokenStream { let ref data = match ast.data { Enum(ref data) => data, _ => unreachable!(), }; let mut next_items = quote! {}; let mut into_iter_items = quote! {}; for v in &data.variants { let ident = &v.ident; next_items = quote! { #next_items RefNode::#ident(x) => x.next(), }; into_iter_items = quote! { #into_iter_items RefNode::#ident(x) => x.into_iter(), }; } let name = &ast.ident; let gen = quote! { impl<'a> #name<'a> { fn next(&self) -> RefNodes<'a> { match self { #next_items } } } impl<'a> IntoIterator for #name<'a> { type Item = RefNode<'a>; type IntoIter = Iter<'a>; fn into_iter(self) -> Self::IntoIter { match self { #into_iter_items } } } }; gen.into() }