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-rw-r--r--src/lower/rust.rs273
1 files changed, 0 insertions, 273 deletions
diff --git a/src/lower/rust.rs b/src/lower/rust.rs
deleted file mode 100644
index 7931306..0000000
--- a/src/lower/rust.rs
+++ /dev/null
@@ -1,273 +0,0 @@
-use std::collections::{BTreeSet, HashMap};
-
-use proc_macro2::{Span, TokenStream, TokenTree};
-use quote::{format_ident, quote};
-
-use crate::chomp::{
- ast,
- typed::{Alt, Cat, Epsilon, Fix, Literal, Typed, TypedExpression, Variable},
-};
-
-use super::{Backend, GenerateCode};
-
-#[derive(Debug)]
-pub struct RustBackend {
- // Indexed by ID, stores type, impl and dependencies
- data: Vec<(TokenStream, TokenStream, BTreeSet<usize>)>,
- eps_id: Option<usize>,
- lit_map: HashMap<String, usize>,
- cat_map: HashMap<(usize, usize), usize>,
- alt_map: HashMap<(usize, usize), usize>,
- fix_map: HashMap<Box<TypedExpression>, usize>,
- var_map: HashMap<usize, usize>, // Key is fix point ID
- context: Vec<usize>,
-}
-
-impl Default for RustBackend {
- fn default() -> Self {
- Self {
- data: Vec::new(),
- eps_id: None,
- lit_map: HashMap::new(),
- cat_map: HashMap::new(),
- alt_map: HashMap::new(),
- fix_map: HashMap::new(),
- var_map: HashMap::new(),
- context: Vec::new(),
- }
- }
-}
-
-impl Backend for RustBackend {
- type Id = usize;
-
- type Code = TokenStream;
-
- fn gen_epsilon(&mut self, _eps: Epsilon) -> Self::Id {
- match self.eps_id {
- Some(id) => id,
- None => {
- let id = self.data.len();
- let ty = quote! { () };
- let tokens = TokenStream::new();
- self.data.push((ty, tokens, BTreeSet::new()));
- id
- }
- }
- }
-
- fn gen_literal(&mut self, lit: Literal) -> Self::Id {
- let lit: ast::Literal = lit.into();
- if let Some(&id) = self.lit_map.get(&lit.value()) {
- id
- } else {
- let id = self.data.len();
- let name = format_ident!("Lit{}", id);
- let doc_name = format!(
- r#"The literal string `"{}"`."#,
- lit.value().escape_debug().collect::<String>()
- );
- let lit = lit.as_litstr(Span::call_site());
- let tokens = quote! {
- #[doc=#doc_name]
- #[derive(Clone, Debug, Eq, Hash, PartialEq)]
- pub struct #name;
-
- impl Parse for #name {
- fn take<P: Parser + ?Sized>(input: &mut P) -> Result<Self, TakeError> {
- input.consume_str(#lit).map(|()| #name)
- }
- }
- };
-
- self.data
- .push((TokenTree::from(name).into(), tokens, BTreeSet::new()));
- self.lit_map.insert(lit.value(), id);
-
- id
- }
- }
-
- fn gen_cat(&mut self, cat: Cat) -> Self::Id {
- let (fst, _punct, snd) = cat.unwrap();
- let fst = fst.gen(self);
- let snd = snd.gen(self);
-
- if let Some(&id) = self.cat_map.get(&(fst, snd)) {
- id
- } else {
- let id = self.data.len();
- let fst_ty = self.data[fst].0.clone();
- let snd_ty = self.data[snd].0.clone();
- self.data.push((
- quote! {(#fst_ty, #snd_ty)},
- TokenStream::new(),
- [fst, snd].iter().cloned().collect(),
- ));
- self.cat_map.insert((fst, snd), id);
- id
- }
- }
-
- fn gen_alt(&mut self, alt: Alt) -> Self::Id {
- let iter_first = alt.get_type().first_set().clone().into_iter();
-
- let (left, _punct, right) = alt.unwrap();
- let left_ty = left.get_type();
- let right_ty = right.get_type();
-
- let left_null = left_ty.nullable();
- let left_first = left_ty.first_set().clone();
-
- let right_null = right_ty.nullable();
- let right_first = right_ty.first_set().clone();
-
- let left = left.gen(self);
- let right = right.gen(self);
-
- if let Some(&id) = self.alt_map.get(&(left, right)) {
- id
- } else {
- let id = self.data.len();
- let left_ty = self.data[left].0.clone();
- let right_ty = self.data[right].0.clone();
- let name = format_ident!("Alt{}", id);
- let mut tokens = quote! {
- #[derive(Clone, Debug, Eq, Hash, PartialEq)]
- pub enum #name {
- Left(#left_ty),
- Right(#right_ty),
- }
- };
-
- let other = if left_null {
- let iter = right_first.into_iter();
-
- quote! {
- impl Parse for #name {
- fn take<P: Parser + ?Sized>(input: &mut P) -> Result<Self, TakeError> {
- match input.peek() {
- #(Some(#iter))|* => input.take().map(Self::Right),
- _ => input.take().map(Self::Left),
- }
- }
- }
- }
- } else if right_null {
- let iter = left_first.into_iter();
-
- quote! {
- impl Parse for #name {
- fn take<P: Parser + ?Sized>(input: &mut P) -> Result<Self, TakeError> {
- match input.peek() {
- #(Some(#iter))|* => input.take().map(Self::Left),
- _ => input.take().map(Self::Right),
- }
- }
- }
- }
- } else {
- let iter_left = left_first.into_iter();
- let iter_right = right_first.into_iter();
-
- quote! {
- impl Parse for #name {
- fn take<P: Parser + ?Sized>(input: &mut P) -> Result<Self, TakeError> {
- match input.peek().ok_or_else(|| TakeError::EndOfStream(input.pos()))? {
- #(#iter_left)|* => input.take().map(Self::Left),
- #(#iter_right)|* => input.take().map(Self::Right),
- c => Err(TakeError::BadBranch(input.pos(), c, &[#(#iter_first),*]))
- }
- }
- }
- }
- };
-
- tokens.extend(other);
- self.data.push((
- TokenTree::from(name).into(),
- tokens,
- [left, right].iter().cloned().collect(),
- ));
- self.alt_map.insert((left, right), id);
- id
- }
- }
-
- fn gen_fix(&mut self, fix: Fix) -> Self::Id {
- let (_arg, inner, _span) = fix.unwrap();
- if let Some(&id) = self.fix_map.get(&inner) {
- id
- } else {
- let id = self.data.len();
- let name = format_ident!("Fix{}", id);
- self.data.push((
- TokenTree::from(name.clone()).into(),
- TokenStream::new(),
- BTreeSet::new(),
- ));
-
- self.context.push(id);
- let inner = inner.gen(self);
- self.context.pop();
-
- let inner_ty = self.data[inner].0.clone();
- let tokens = quote! {
- #[derive(Clone, Debug, Eq, Hash, PartialEq)]
- pub struct #name(#inner_ty);
-
- impl Parse for #name {
- fn take<P: Parser + ?Sized>(input: &mut P) -> Result<Self, TakeError> {
- input.take().map(Self)
- }
- }
- };
- self.data[id].1 = tokens;
- self.data[id].2 = [inner].iter().cloned().collect();
- id
- }
- }
-
- fn gen_variable(&mut self, var: Variable) -> Self::Id {
- let fix_id = self.context[self.context.len() - var.index() - 1];
- if let Some(&id) = self.var_map.get(&fix_id) {
- id
- } else {
- let id = self.data.len();
- let fix_ty = self.data[fix_id].0.clone();
- let name = quote! {Box<#fix_ty>};
- self.data.push((name, TokenStream::new(), BTreeSet::new()));
- self.var_map.insert(fix_id, id);
- id
- }
- }
-
- fn emit_code(self, id: Self::Id) -> Self::Code {
- let mut tokens = quote! {
- use ::chewed::*;
- };
-
- let (root_ty, root_impl, mut todo) = self.data[id].clone();
- tokens.extend(root_impl);
- let mut completed = [id].iter().cloned().collect::<BTreeSet<_>>();
-
- while !todo.is_empty() {
- let mut next = BTreeSet::new();
- completed.extend(todo.clone());
-
- for ty in todo {
- let ty = self.data[ty].clone();
- tokens.extend(ty.1);
- next.extend(ty.2.into_iter().filter(|id| !completed.contains(id)));
- }
-
- todo = next;
- }
-
- tokens.extend(quote! {
- pub type Ast = #root_ty;
- });
-
- tokens
- }
-}
generated by cgit v1.2.3 (git 2.49.0) at 2025-04-30 07:30:04 +0000