Lawrence Bethlenfalvy
329dea72b7
Also fixed the name collector, and lambda parameters are no longer resolved at parsing to support planned macro-based pattern matching. The rule matcher clones a lot, the number of clones could be zero.
122 lines
4.4 KiB
Rust
122 lines
4.4 KiB
Rust
use std::{collections::HashMap};
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use thiserror::Error;
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use crate::utils::Stackframe;
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use crate::expression::{Expr, Clause};
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type ImportMap = HashMap<String, Vec<String>>;
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#[derive(Debug, Clone, Error)]
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pub enum ResolutionError<Err> {
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#[error("Reference cycle at {0:?}")]
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Cycle(Vec<Vec<String>>),
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#[error("No module provides {0:?}")]
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NoModule(Vec<String>),
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#[error(transparent)]
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Delegate(#[from] Err)
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}
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/// Recursively resolves symbols to their original names in expressions while caching every
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/// resolution. This makes the resolution process lightning fast and invalidation completely
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/// impossible since the intermediate steps of a resolution aren't stored.
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pub struct NameResolver<FSplit, FImps, E> {
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cache: HashMap<Vec<String>, Result<Vec<String>, ResolutionError<E>>>,
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get_modname: FSplit,
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get_imports: FImps
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}
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impl<FSplit, FImps, E> NameResolver<FSplit, FImps, E>
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where
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FSplit: FnMut(&Vec<String>) -> Option<Vec<String>>,
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FImps: FnMut(&Vec<String>) -> Result<ImportMap, E>,
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E: Clone
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{
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pub fn new(get_modname: FSplit, get_imports: FImps) -> Self {
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Self {
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cache: HashMap::new(),
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get_modname,
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get_imports
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}
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}
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/// Obtains a symbol's originnal name
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/// Uses a substack to detect loops
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fn find_origin_rec<'a>(
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&mut self,
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symbol: &'a Vec<String>,
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import_path: Stackframe<'a, &'a Vec<String>>
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) -> Result<Vec<String>, ResolutionError<E>> {
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if let Some(cached) = self.cache.get(symbol) { return cached.clone() }
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// The imports and path of the referenced file and the local name
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let path = (self.get_modname)(symbol).ok_or(ResolutionError::NoModule(symbol.clone()))?;
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let (_, name) = symbol.split_at(path.len());
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let imports = (self.get_imports)(&path)?;
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let result = if let Some(source) = imports.get(&name[0]) {
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let new_sym: Vec<String> = source.iter().chain(name.iter()).cloned().collect();
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if import_path.iter().any(|el| el == &&new_sym) {
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Err(ResolutionError::Cycle(import_path.iter().cloned().cloned().collect()))
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} else {
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self.find_origin_rec(&new_sym, import_path.push(symbol))
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}
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} else {
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Ok(symbol.clone()) // If not imported, it must be locally defined
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};
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self.cache.insert(symbol.clone(), result.clone());
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return result
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}
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fn process_exprv_rec(&mut self, exv: &[Expr]) -> Result<Vec<Expr>, ResolutionError<E>> {
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exv.iter().map(|ex| self.process_expression_rec(ex)).collect()
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}
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fn process_exprboxopt_rec(&mut self,
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exbo: &Option<Box<Expr>>
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) -> Result<Option<Box<Expr>>, ResolutionError<E>> {
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exbo.iter().map(|exb| Ok(Box::new(self.process_expression_rec(exb.as_ref())?)))
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.next().transpose()
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}
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fn process_clause_rec(&mut self, tok: &Clause) -> Result<Clause, ResolutionError<E>> {
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Ok(match tok {
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Clause::S(c, exv) => Clause::S(*c,
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exv.iter().map(|e| self.process_expression_rec(e))
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.collect::<Result<Vec<Expr>, ResolutionError<E>>>()?
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),
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Clause::Lambda(name, typ, body) => Clause::Lambda(name.clone(),
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self.process_exprv_rec(typ)?,
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self.process_exprv_rec(body)?
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),
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Clause::Auto(name, typ, body) => Clause::Auto(name.clone(),
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self.process_exprv_rec(typ)?,
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self.process_exprv_rec(body)?
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),
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Clause::Name{local, qualified} => Clause::Name{
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local: local.clone(),
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qualified: self.find_origin(qualified)?
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},
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x => x.clone()
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})
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}
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fn process_expression_rec(&mut self, Expr(token, typ): &Expr) -> Result<Expr, ResolutionError<E>> {
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Ok(Expr(
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self.process_clause_rec(token)?,
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self.process_exprboxopt_rec(typ)?
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))
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}
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pub fn find_origin(&mut self, symbol: &Vec<String>) -> Result<Vec<String>, ResolutionError<E>> {
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self.find_origin_rec(symbol, Stackframe::new(symbol))
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}
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#[allow(dead_code)]
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pub fn process_clause(&mut self, clause: &Clause) -> Result<Clause, ResolutionError<E>> {
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self.process_clause_rec(clause)
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}
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pub fn process_expression(&mut self, ex: &Expr) -> Result<Expr, ResolutionError<E>> {
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self.process_expression_rec(ex)
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}
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} |