892 lines
34 KiB
Rust
892 lines
34 KiB
Rust
use super::item::{ParseItem, ParseItemSet, ParseItemSetCore};
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use super::item_set_builder::ParseItemSetBuilder;
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use crate::error::{Error, Result};
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use crate::generate::grammars::{
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InlinedProductionMap, LexicalGrammar, SyntaxGrammar, VariableType,
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};
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use crate::generate::node_types::VariableInfo;
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use crate::generate::rules::{Associativity, Symbol, SymbolType, TokenSet};
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use crate::generate::tables::{
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FieldLocation, GotoAction, ParseAction, ParseState, ParseStateId, ParseTable, ParseTableEntry,
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ProductionInfo, ProductionInfoId,
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};
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use core::ops::Range;
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use std::collections::hash_map::Entry;
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use std::collections::{BTreeMap, HashMap, HashSet, VecDeque};
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use std::fmt::Write;
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use std::u32;
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// For conflict reporting, each parse state is associated with an example
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// sequence of symbols that could lead to that parse state.
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type SymbolSequence = Vec<Symbol>;
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type AuxiliarySymbolSequence = Vec<AuxiliarySymbolInfo>;
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pub(crate) type ParseStateInfo<'a> = (SymbolSequence, ParseItemSet<'a>);
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#[derive(Clone)]
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struct AuxiliarySymbolInfo {
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auxiliary_symbol: Symbol,
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parent_symbols: Vec<Symbol>,
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}
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struct ParseStateQueueEntry {
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state_id: ParseStateId,
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preceding_auxiliary_symbols: AuxiliarySymbolSequence,
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}
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struct ParseTableBuilder<'a> {
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item_set_builder: ParseItemSetBuilder<'a>,
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syntax_grammar: &'a SyntaxGrammar,
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lexical_grammar: &'a LexicalGrammar,
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variable_info: &'a Vec<VariableInfo>,
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core_ids_by_core: HashMap<ParseItemSetCore<'a>, usize>,
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state_ids_by_item_set: HashMap<ParseItemSet<'a>, ParseStateId>,
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parse_state_info_by_id: Vec<ParseStateInfo<'a>>,
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parse_state_queue: VecDeque<ParseStateQueueEntry>,
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non_terminal_extra_states: Vec<(Symbol, usize)>,
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parse_table: ParseTable,
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}
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impl<'a> ParseTableBuilder<'a> {
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fn build(mut self) -> Result<(ParseTable, Vec<ParseStateInfo<'a>>)> {
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// Ensure that the empty alias sequence has index 0.
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self.parse_table
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.production_infos
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.push(ProductionInfo::default());
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// Add the error state at index 0.
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self.add_parse_state(&Vec::new(), &Vec::new(), ParseItemSet::default(), false);
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// Add the starting state at index 1.
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self.add_parse_state(
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&Vec::new(),
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&Vec::new(),
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ParseItemSet::with(
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[(
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ParseItem::start(),
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[Symbol::end()].iter().cloned().collect(),
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)]
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.iter()
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.cloned(),
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),
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false,
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);
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// Compute the possible item sets for non-terminal extras.
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let mut non_terminal_extra_item_sets_by_first_terminal = BTreeMap::new();
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for extra_non_terminal in self
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.syntax_grammar
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.extra_symbols
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.iter()
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.filter(|s| s.is_non_terminal())
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{
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let variable = &self.syntax_grammar.variables[extra_non_terminal.index];
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for production in &variable.productions {
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non_terminal_extra_item_sets_by_first_terminal
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.entry(production.first_symbol().unwrap())
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.or_insert(ParseItemSet::default())
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.insert(
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ParseItem {
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variable_index: extra_non_terminal.index as u32,
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production,
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step_index: 1,
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},
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&[Symbol::end()].iter().cloned().collect(),
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);
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}
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}
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// Add a state for each starting terminal of a non-terminal extra rule.
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for (terminal, item_set) in non_terminal_extra_item_sets_by_first_terminal {
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self.non_terminal_extra_states
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.push((terminal, self.parse_table.states.len()));
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self.add_parse_state(&Vec::new(), &Vec::new(), item_set, true);
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}
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while let Some(entry) = self.parse_state_queue.pop_front() {
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let item_set = self
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.item_set_builder
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.transitive_closure(&self.parse_state_info_by_id[entry.state_id].1);
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self.add_actions(
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self.parse_state_info_by_id[entry.state_id].0.clone(),
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entry.preceding_auxiliary_symbols,
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entry.state_id,
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item_set,
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)?;
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}
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self.remove_precedences();
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Ok((self.parse_table, self.parse_state_info_by_id))
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}
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fn add_parse_state(
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&mut self,
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preceding_symbols: &SymbolSequence,
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preceding_auxiliary_symbols: &AuxiliarySymbolSequence,
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item_set: ParseItemSet<'a>,
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is_non_terminal_extra: bool,
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) -> ParseStateId {
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match self.state_ids_by_item_set.entry(item_set) {
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// If an equivalent item set has already been processed, then return
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// the existing parse state index.
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Entry::Occupied(o) => *o.get(),
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// Otherwise, insert a new parse state and add it to the queue of
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// parse states to populate.
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Entry::Vacant(v) => {
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let core = v.key().core();
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let core_count = self.core_ids_by_core.len();
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let core_id = match self.core_ids_by_core.entry(core) {
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Entry::Occupied(e) => *e.get(),
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Entry::Vacant(e) => {
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e.insert(core_count);
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core_count
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}
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};
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let state_id = self.parse_table.states.len();
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self.parse_state_info_by_id
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.push((preceding_symbols.clone(), v.key().clone()));
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self.parse_table.states.push(ParseState {
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id: state_id,
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lex_state_id: 0,
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external_lex_state_id: 0,
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terminal_entries: HashMap::new(),
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nonterminal_entries: HashMap::new(),
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core_id,
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is_non_terminal_extra,
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});
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self.parse_state_queue.push_back(ParseStateQueueEntry {
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state_id,
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preceding_auxiliary_symbols: preceding_auxiliary_symbols.clone(),
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});
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v.insert(state_id);
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state_id
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}
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}
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}
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fn add_actions(
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&mut self,
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mut preceding_symbols: SymbolSequence,
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mut preceding_auxiliary_symbols: Vec<AuxiliarySymbolInfo>,
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state_id: ParseStateId,
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item_set: ParseItemSet<'a>,
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) -> Result<()> {
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let mut terminal_successors = BTreeMap::new();
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let mut non_terminal_successors = BTreeMap::new();
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let mut lookaheads_with_conflicts = TokenSet::new();
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// Each item in the item set contributes to either or a Shift action or a Reduce
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// action in this state.
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for (item, lookaheads) in &item_set.entries {
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// If the item is unfinished, then this state has a transition for the item's
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// next symbol. Advance the item to its next step and insert the resulting
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// item into the successor item set.
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if let Some(next_symbol) = item.symbol() {
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let successor = item.successor();
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if next_symbol.is_non_terminal() {
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// Keep track of where auxiliary non-terminals (repeat symbols) are
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// used within visible symbols. This information may be needed later
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// for conflict resolution.
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if self.syntax_grammar.variables[next_symbol.index].is_auxiliary() {
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preceding_auxiliary_symbols
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.push(self.get_auxiliary_node_info(&item_set, next_symbol));
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}
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non_terminal_successors
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.entry(next_symbol)
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.or_insert_with(|| ParseItemSet::default())
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.insert(successor, lookaheads);
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} else {
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terminal_successors
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.entry(next_symbol)
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.or_insert_with(|| ParseItemSet::default())
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.insert(successor, lookaheads);
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}
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}
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// If the item is finished, then add a Reduce action to this state based
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// on this item.
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else {
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let action = if item.is_augmented() {
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ParseAction::Accept
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} else {
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ParseAction::Reduce {
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symbol: Symbol::non_terminal(item.variable_index as usize),
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child_count: item.step_index as usize,
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precedence: item.precedence(),
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associativity: item.associativity(),
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dynamic_precedence: item.production.dynamic_precedence,
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production_id: self.get_production_id(item),
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}
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};
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for lookahead in lookaheads.iter() {
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let entry = self.parse_table.states[state_id]
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.terminal_entries
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.entry(lookahead);
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let entry = entry.or_insert_with(|| ParseTableEntry::new());
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// While inserting Reduce actions, eagerly resolve conflicts related
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// to precedence: avoid inserting lower-precedence reductions, and
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// clear the action list when inserting higher-precedence reductions.
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if entry.actions.is_empty() {
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entry.actions.push(action);
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} else if action.precedence() > entry.actions[0].precedence() {
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entry.actions.clear();
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entry.actions.push(action);
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lookaheads_with_conflicts.remove(&lookahead);
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} else if action.precedence() == entry.actions[0].precedence() {
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entry.actions.push(action);
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lookaheads_with_conflicts.insert(lookahead);
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}
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}
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}
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}
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// Having computed the the successor item sets for each symbol, add a new
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// parse state for each of these item sets, and add a corresponding Shift
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// action to this state.
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for (symbol, next_item_set) in terminal_successors {
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preceding_symbols.push(symbol);
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let next_state_id = self.add_parse_state(
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&preceding_symbols,
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&preceding_auxiliary_symbols,
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next_item_set,
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self.parse_table.states[state_id].is_non_terminal_extra,
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);
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preceding_symbols.pop();
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let entry = self.parse_table.states[state_id]
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.terminal_entries
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.entry(symbol);
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if let Entry::Occupied(e) = &entry {
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if !e.get().actions.is_empty() {
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lookaheads_with_conflicts.insert(symbol);
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}
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}
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entry
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.or_insert_with(|| ParseTableEntry::new())
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.actions
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.push(ParseAction::Shift {
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state: next_state_id,
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is_repetition: false,
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});
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}
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for (symbol, next_item_set) in non_terminal_successors {
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preceding_symbols.push(symbol);
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let next_state_id = self.add_parse_state(
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&preceding_symbols,
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&preceding_auxiliary_symbols,
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next_item_set,
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self.parse_table.states[state_id].is_non_terminal_extra,
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);
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preceding_symbols.pop();
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self.parse_table.states[state_id]
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.nonterminal_entries
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.insert(symbol, GotoAction::Goto(next_state_id));
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}
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// For any symbol with multiple actions, perform conflict resolution.
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// This will either
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// * choose one action over the others using precedence or associativity
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// * keep multiple actions if this conflict has been whitelisted in the grammar
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// * fail, terminating the parser generation process
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for symbol in lookaheads_with_conflicts.iter() {
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self.handle_conflict(
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&item_set,
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state_id,
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&preceding_symbols,
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&preceding_auxiliary_symbols,
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symbol,
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)?;
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}
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// Finally, add actions for the grammar's `extra` symbols.
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let state = &mut self.parse_table.states[state_id];
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let is_non_terminal_extra = state.is_non_terminal_extra;
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let is_end_of_non_terminal_extra =
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is_non_terminal_extra && state.terminal_entries.len() == 1;
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// Add actions for the start tokens of each non-terminal extra rule.
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// These actions are added to every state except for the states that are
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// alread within non-terminal extras. Non-terminal extras are not allowed
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// to nest within each other.
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if !is_non_terminal_extra {
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for (terminal, state_id) in &self.non_terminal_extra_states {
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state
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.terminal_entries
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.entry(*terminal)
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.or_insert(ParseTableEntry {
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reusable: true,
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actions: vec![ParseAction::Shift {
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state: *state_id,
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is_repetition: false,
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}],
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});
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}
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}
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// Add ShiftExtra actions for the terminal extra tokens. These actions
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// are added to every state except for those at the ends of non-terminal
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// extras.
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if !is_end_of_non_terminal_extra {
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for extra_token in &self.syntax_grammar.extra_symbols {
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if extra_token.is_non_terminal() {
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state
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.nonterminal_entries
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.insert(*extra_token, GotoAction::ShiftExtra);
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} else {
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state
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.terminal_entries
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.entry(*extra_token)
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.or_insert(ParseTableEntry {
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reusable: true,
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actions: vec![ParseAction::ShiftExtra],
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});
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}
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}
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}
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Ok(())
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}
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fn handle_conflict(
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&mut self,
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item_set: &ParseItemSet,
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state_id: ParseStateId,
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preceding_symbols: &SymbolSequence,
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preceding_auxiliary_symbols: &Vec<AuxiliarySymbolInfo>,
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conflicting_lookahead: Symbol,
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) -> Result<()> {
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let entry = self.parse_table.states[state_id]
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.terminal_entries
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.get_mut(&conflicting_lookahead)
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.unwrap();
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// Determine which items in the set conflict with each other, and the
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// precedences associated with SHIFT vs REDUCE actions. There won't
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// be multiple REDUCE actions with different precedences; that is
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// sorted out ahead of time in `add_actions`. But there can still be
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// REDUCE-REDUCE conflicts where all actions have the *same*
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// precedence, and there can still be SHIFT/REDUCE conflicts.
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let reduce_precedence = entry.actions[0].precedence();
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let mut considered_associativity = false;
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let mut shift_precedence: Option<Range<i32>> = None;
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let mut conflicting_items = HashSet::new();
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for (item, lookaheads) in &item_set.entries {
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if let Some(step) = item.step() {
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if item.step_index > 0 {
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if self
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.item_set_builder
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.first_set(&step.symbol)
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.contains(&conflicting_lookahead)
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{
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if item.variable_index != u32::MAX {
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conflicting_items.insert(item);
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}
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let precedence = item.precedence();
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if let Some(range) = &mut shift_precedence {
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if precedence < range.start {
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range.start = precedence;
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} else if precedence > range.end {
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range.end = precedence;
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}
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} else {
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shift_precedence = Some(precedence..precedence);
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}
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}
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}
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} else if lookaheads.contains(&conflicting_lookahead) {
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if item.variable_index != u32::MAX {
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conflicting_items.insert(item);
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}
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}
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}
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if let ParseAction::Shift { is_repetition, .. } = entry.actions.last_mut().unwrap() {
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let shift_precedence = shift_precedence.unwrap_or(0..0);
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// If all of the items in the conflict have the same parent symbol,
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// and that parent symbols is auxiliary, then this is just the intentional
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// ambiguity associated with a repeat rule. Resolve that class of ambiguity
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// by leaving it in the parse table, but marking the SHIFT action with
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// an `is_repetition` flag.
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let conflicting_variable_index =
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conflicting_items.iter().next().unwrap().variable_index;
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if self.syntax_grammar.variables[conflicting_variable_index as usize].is_auxiliary()
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&& conflicting_items
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.iter()
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.all(|item| item.variable_index == conflicting_variable_index)
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{
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*is_repetition = true;
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return Ok(());
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}
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// If the SHIFT action has higher precedence, remove all the REDUCE actions.
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if shift_precedence.start > reduce_precedence
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|| (shift_precedence.start == reduce_precedence
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&& shift_precedence.end > reduce_precedence)
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{
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entry.actions.drain(0..entry.actions.len() - 1);
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}
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// If the REDUCE actions have higher precedence, remove the SHIFT action.
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else if shift_precedence.end < reduce_precedence
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|| (shift_precedence.end == reduce_precedence
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&& shift_precedence.start < reduce_precedence)
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{
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entry.actions.pop();
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conflicting_items.retain(|item| item.is_done());
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}
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// If the SHIFT and REDUCE actions have the same predence, consider
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// the REDUCE actions' associativity.
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else if shift_precedence == (reduce_precedence..reduce_precedence) {
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considered_associativity = true;
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let mut has_left = false;
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let mut has_right = false;
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let mut has_non = false;
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for action in &entry.actions {
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if let ParseAction::Reduce { associativity, .. } = action {
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match associativity {
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Some(Associativity::Left) => has_left = true,
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Some(Associativity::Right) => has_right = true,
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None => has_non = true,
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}
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}
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}
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// If all Reduce actions are left associative, remove the SHIFT action.
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// If all Reduce actions are right associative, remove the REDUCE actions.
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match (has_left, has_non, has_right) {
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(true, false, false) => {
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entry.actions.pop();
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conflicting_items.retain(|item| item.is_done());
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}
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(false, false, true) => {
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entry.actions.drain(0..entry.actions.len() - 1);
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}
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_ => {}
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}
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}
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}
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// If all of the actions but one have been eliminated, then there's no problem.
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let entry = self.parse_table.states[state_id]
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.terminal_entries
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.get_mut(&conflicting_lookahead)
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.unwrap();
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if entry.actions.len() == 1 {
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return Ok(());
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}
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// Determine the set of parent symbols involved in this conflict.
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let mut actual_conflict = Vec::new();
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for item in &conflicting_items {
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let symbol = Symbol::non_terminal(item.variable_index as usize);
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if self.syntax_grammar.variables[symbol.index].is_auxiliary() {
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actual_conflict.extend(
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preceding_auxiliary_symbols
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.iter()
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.rev()
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.find_map(|info| {
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|
if info.auxiliary_symbol == symbol {
|
|
Some(&info.parent_symbols)
|
|
} else {
|
|
None
|
|
}
|
|
})
|
|
.unwrap()
|
|
.iter(),
|
|
);
|
|
} else {
|
|
actual_conflict.push(symbol);
|
|
}
|
|
}
|
|
actual_conflict.sort_unstable();
|
|
actual_conflict.dedup();
|
|
|
|
// If this set of symbols has been whitelisted, then there's no error.
|
|
if self
|
|
.syntax_grammar
|
|
.expected_conflicts
|
|
.contains(&actual_conflict)
|
|
{
|
|
return Ok(());
|
|
}
|
|
|
|
let mut msg = "Unresolved conflict for symbol sequence:\n\n".to_string();
|
|
for symbol in preceding_symbols {
|
|
write!(&mut msg, " {}", self.symbol_name(symbol)).unwrap();
|
|
}
|
|
|
|
write!(
|
|
&mut msg,
|
|
" • {} …\n\n",
|
|
self.symbol_name(&conflicting_lookahead)
|
|
)
|
|
.unwrap();
|
|
write!(&mut msg, "Possible interpretations:\n\n").unwrap();
|
|
|
|
let mut interpretions = conflicting_items
|
|
.iter()
|
|
.map(|item| {
|
|
let mut line = String::new();
|
|
for preceding_symbol in preceding_symbols
|
|
.iter()
|
|
.take(preceding_symbols.len() - item.step_index as usize)
|
|
{
|
|
write!(&mut line, " {}", self.symbol_name(preceding_symbol)).unwrap();
|
|
}
|
|
|
|
write!(
|
|
&mut line,
|
|
" ({}",
|
|
&self.syntax_grammar.variables[item.variable_index as usize].name
|
|
)
|
|
.unwrap();
|
|
|
|
for (j, step) in item.production.steps.iter().enumerate() {
|
|
if j as u32 == item.step_index {
|
|
write!(&mut line, " •").unwrap();
|
|
}
|
|
write!(&mut line, " {}", self.symbol_name(&step.symbol)).unwrap();
|
|
}
|
|
|
|
write!(&mut line, ")").unwrap();
|
|
|
|
if item.is_done() {
|
|
write!(
|
|
&mut line,
|
|
" • {} …",
|
|
self.symbol_name(&conflicting_lookahead)
|
|
)
|
|
.unwrap();
|
|
}
|
|
|
|
let precedence = item.precedence();
|
|
let associativity = item.associativity();
|
|
|
|
let prec_line = if let Some(associativity) = associativity {
|
|
Some(format!(
|
|
"(precedence: {}, associativity: {:?})",
|
|
precedence, associativity
|
|
))
|
|
} else if precedence > 0 {
|
|
Some(format!("(precedence: {})", precedence))
|
|
} else {
|
|
None
|
|
};
|
|
|
|
(line, prec_line)
|
|
})
|
|
.collect::<Vec<_>>();
|
|
|
|
let max_interpretation_length = interpretions
|
|
.iter()
|
|
.map(|i| i.0.chars().count())
|
|
.max()
|
|
.unwrap();
|
|
interpretions.sort_unstable();
|
|
for (i, (line, prec_suffix)) in interpretions.into_iter().enumerate() {
|
|
write!(&mut msg, " {}:", i + 1).unwrap();
|
|
msg += &line;
|
|
if let Some(prec_suffix) = prec_suffix {
|
|
for _ in line.chars().count()..max_interpretation_length {
|
|
msg.push(' ');
|
|
}
|
|
msg += " ";
|
|
msg += &prec_suffix;
|
|
}
|
|
msg.push('\n');
|
|
}
|
|
|
|
let mut resolution_count = 0;
|
|
write!(&mut msg, "\nPossible resolutions:\n\n").unwrap();
|
|
let mut shift_items = Vec::new();
|
|
let mut reduce_items = Vec::new();
|
|
for item in conflicting_items {
|
|
if item.is_done() {
|
|
reduce_items.push(item);
|
|
} else {
|
|
shift_items.push(item);
|
|
}
|
|
}
|
|
shift_items.sort_unstable();
|
|
reduce_items.sort_unstable();
|
|
if actual_conflict.len() > 1 {
|
|
if shift_items.len() > 0 {
|
|
resolution_count += 1;
|
|
write!(
|
|
&mut msg,
|
|
" {}: Specify a higher precedence in",
|
|
resolution_count
|
|
)
|
|
.unwrap();
|
|
for (i, item) in shift_items.iter().enumerate() {
|
|
if i > 0 {
|
|
write!(&mut msg, " and").unwrap();
|
|
}
|
|
write!(
|
|
&mut msg,
|
|
" `{}`",
|
|
self.symbol_name(&Symbol::non_terminal(item.variable_index as usize))
|
|
)
|
|
.unwrap();
|
|
}
|
|
write!(&mut msg, " than in the other rules.\n").unwrap();
|
|
}
|
|
|
|
for item in &reduce_items {
|
|
resolution_count += 1;
|
|
write!(
|
|
&mut msg,
|
|
" {}: Specify a higher precedence in `{}` than in the other rules.\n",
|
|
resolution_count,
|
|
self.symbol_name(&Symbol::non_terminal(item.variable_index as usize))
|
|
)
|
|
.unwrap();
|
|
}
|
|
}
|
|
|
|
if considered_associativity {
|
|
resolution_count += 1;
|
|
write!(
|
|
&mut msg,
|
|
" {}: Specify a left or right associativity in ",
|
|
resolution_count
|
|
)
|
|
.unwrap();
|
|
for (i, item) in reduce_items.iter().enumerate() {
|
|
if i > 0 {
|
|
write!(&mut msg, " and ").unwrap();
|
|
}
|
|
write!(
|
|
&mut msg,
|
|
"`{}`",
|
|
self.symbol_name(&Symbol::non_terminal(item.variable_index as usize))
|
|
)
|
|
.unwrap();
|
|
}
|
|
write!(&mut msg, "\n").unwrap();
|
|
}
|
|
|
|
resolution_count += 1;
|
|
write!(
|
|
&mut msg,
|
|
" {}: Add a conflict for these rules: ",
|
|
resolution_count
|
|
)
|
|
.unwrap();
|
|
for (i, symbol) in actual_conflict.iter().enumerate() {
|
|
if i > 0 {
|
|
write!(&mut msg, ", ").unwrap();
|
|
}
|
|
write!(&mut msg, "`{}`", self.symbol_name(symbol)).unwrap();
|
|
}
|
|
write!(&mut msg, "\n").unwrap();
|
|
|
|
Err(Error::new(msg))
|
|
}
|
|
|
|
fn get_auxiliary_node_info(
|
|
&self,
|
|
item_set: &ParseItemSet,
|
|
symbol: Symbol,
|
|
) -> AuxiliarySymbolInfo {
|
|
let parent_symbols = item_set
|
|
.entries
|
|
.iter()
|
|
.filter_map(|(item, _)| {
|
|
let variable_index = item.variable_index as usize;
|
|
if item.symbol() == Some(symbol)
|
|
&& !self.syntax_grammar.variables[variable_index].is_auxiliary()
|
|
{
|
|
Some(Symbol::non_terminal(variable_index))
|
|
} else {
|
|
None
|
|
}
|
|
})
|
|
.collect();
|
|
AuxiliarySymbolInfo {
|
|
auxiliary_symbol: symbol,
|
|
parent_symbols,
|
|
}
|
|
}
|
|
|
|
fn remove_precedences(&mut self) {
|
|
for state in self.parse_table.states.iter_mut() {
|
|
for (_, entry) in state.terminal_entries.iter_mut() {
|
|
for action in entry.actions.iter_mut() {
|
|
match action {
|
|
ParseAction::Reduce {
|
|
precedence,
|
|
associativity,
|
|
..
|
|
} => {
|
|
*precedence = 0;
|
|
*associativity = None;
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn get_production_id(&mut self, item: &ParseItem) -> ProductionInfoId {
|
|
let mut production_info = ProductionInfo {
|
|
alias_sequence: Vec::new(),
|
|
field_map: BTreeMap::new(),
|
|
};
|
|
|
|
for (i, step) in item.production.steps.iter().enumerate() {
|
|
production_info.alias_sequence.push(step.alias.clone());
|
|
if let Some(field_name) = &step.field_name {
|
|
production_info
|
|
.field_map
|
|
.entry(field_name.clone())
|
|
.or_insert(Vec::new())
|
|
.push(FieldLocation {
|
|
index: i,
|
|
inherited: false,
|
|
});
|
|
}
|
|
|
|
if step.symbol.kind == SymbolType::NonTerminal
|
|
&& !self.syntax_grammar.variables[step.symbol.index]
|
|
.kind
|
|
.is_visible()
|
|
{
|
|
let info = &self.variable_info[step.symbol.index];
|
|
for (field_name, _) in &info.fields {
|
|
production_info
|
|
.field_map
|
|
.entry(field_name.clone())
|
|
.or_insert(Vec::new())
|
|
.push(FieldLocation {
|
|
index: i,
|
|
inherited: true,
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
while production_info.alias_sequence.last() == Some(&None) {
|
|
production_info.alias_sequence.pop();
|
|
}
|
|
|
|
if item.production.steps.len() > self.parse_table.max_aliased_production_length {
|
|
self.parse_table.max_aliased_production_length = item.production.steps.len()
|
|
}
|
|
|
|
if let Some(index) = self
|
|
.parse_table
|
|
.production_infos
|
|
.iter()
|
|
.position(|seq| *seq == production_info)
|
|
{
|
|
index
|
|
} else {
|
|
self.parse_table.production_infos.push(production_info);
|
|
self.parse_table.production_infos.len() - 1
|
|
}
|
|
}
|
|
|
|
fn symbol_name(&self, symbol: &Symbol) -> String {
|
|
match symbol.kind {
|
|
SymbolType::End => "EOF".to_string(),
|
|
SymbolType::External => self.syntax_grammar.external_tokens[symbol.index]
|
|
.name
|
|
.clone(),
|
|
SymbolType::NonTerminal => self.syntax_grammar.variables[symbol.index].name.clone(),
|
|
SymbolType::Terminal => {
|
|
let variable = &self.lexical_grammar.variables[symbol.index];
|
|
if variable.kind == VariableType::Named {
|
|
variable.name.clone()
|
|
} else {
|
|
format!("'{}'", &variable.name)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn populate_following_tokens(
|
|
result: &mut Vec<TokenSet>,
|
|
grammar: &SyntaxGrammar,
|
|
inlines: &InlinedProductionMap,
|
|
builder: &ParseItemSetBuilder,
|
|
) {
|
|
let productions = grammar
|
|
.variables
|
|
.iter()
|
|
.flat_map(|v| &v.productions)
|
|
.chain(&inlines.productions);
|
|
let all_tokens = (0..result.len())
|
|
.into_iter()
|
|
.map(Symbol::terminal)
|
|
.collect::<TokenSet>();
|
|
for production in productions {
|
|
for i in 1..production.steps.len() {
|
|
let left_tokens = builder.last_set(&production.steps[i - 1].symbol);
|
|
let right_tokens = builder.first_set(&production.steps[i].symbol);
|
|
for left_token in left_tokens.iter() {
|
|
if left_token.is_terminal() {
|
|
result[left_token.index].insert_all_terminals(right_tokens);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
for extra in &grammar.extra_symbols {
|
|
if extra.is_terminal() {
|
|
for entry in result.iter_mut() {
|
|
entry.insert(*extra);
|
|
}
|
|
result[extra.index] = all_tokens.clone();
|
|
}
|
|
}
|
|
}
|
|
|
|
pub(crate) fn build_parse_table<'a>(
|
|
syntax_grammar: &'a SyntaxGrammar,
|
|
lexical_grammar: &'a LexicalGrammar,
|
|
inlines: &'a InlinedProductionMap,
|
|
variable_info: &'a Vec<VariableInfo>,
|
|
) -> Result<(ParseTable, Vec<TokenSet>, Vec<ParseStateInfo<'a>>)> {
|
|
let item_set_builder = ParseItemSetBuilder::new(syntax_grammar, lexical_grammar, inlines);
|
|
let mut following_tokens = vec![TokenSet::new(); lexical_grammar.variables.len()];
|
|
populate_following_tokens(
|
|
&mut following_tokens,
|
|
syntax_grammar,
|
|
inlines,
|
|
&item_set_builder,
|
|
);
|
|
|
|
let (table, item_sets) = ParseTableBuilder {
|
|
syntax_grammar,
|
|
lexical_grammar,
|
|
item_set_builder,
|
|
variable_info,
|
|
non_terminal_extra_states: Vec::new(),
|
|
state_ids_by_item_set: HashMap::new(),
|
|
core_ids_by_core: HashMap::new(),
|
|
parse_state_info_by_id: Vec::new(),
|
|
parse_state_queue: VecDeque::new(),
|
|
parse_table: ParseTable {
|
|
states: Vec::new(),
|
|
symbols: Vec::new(),
|
|
external_lex_states: Vec::new(),
|
|
production_infos: Vec::new(),
|
|
max_aliased_production_length: 1,
|
|
},
|
|
}
|
|
.build()?;
|
|
|
|
Ok((table, following_tokens, item_sets))
|
|
}
|