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🎨 build_parse_table

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This commit is contained in:
Max Brunsfeld 2017-07-07 13:59:57 -07:00
parent 0de93b3bf2
commit c91ceaaa8d
1 changed files with 22 additions and 32 deletions
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54
src/compiler/build_tables/build_parse_table.cc
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@ -39,53 +39,41 @@ class ParseTableBuilder {
ParseItemSetBuilder item_set_builder;
set<const Production *> fragile_productions;
vector<set<Symbol>> incompatible_tokens_by_index;
bool allow_any_conflict;
bool processing_recovery_states;
public:
ParseTableBuilder(const SyntaxGrammar &grammar,
const LexicalGrammar &lex_grammar)
: grammar(grammar),
lexical_grammar(lex_grammar),
item_set_builder(grammar, lex_grammar),
allow_any_conflict(false) {}
ParseTableBuilder(const SyntaxGrammar &grammar, const LexicalGrammar &lex_grammar)
: grammar(grammar),
lexical_grammar(lex_grammar),
item_set_builder(grammar, lex_grammar),
processing_recovery_states(false) {}
pair<ParseTable, CompileError> build() {
Symbol start_symbol = grammar.variables.empty() ?
Symbol::terminal(0) :
Symbol::non_terminal(0);
Production start_production{{{start_symbol, 0, rules::AssociativityNone}}, 0};
Production start_production{
{ProductionStep{start_symbol, 0, rules::AssociativityNone}},
0
};
// Placeholder for error state
add_parse_state(ParseItemSet());
ParseStateId error_state_id = add_parse_state(ParseItemSet());
add_parse_state(ParseItemSet({
{
ParseItem(rules::START(), start_production, 0),
LookaheadSet({ END_OF_INPUT() }),
LookaheadSet({END_OF_INPUT()}),
},
}));
CompileError error = process_part_state_queue();
if (error.type != TSCompileErrorTypeNone) {
return { parse_table, error };
}
if (error.type != TSCompileErrorTypeNone) return {parse_table, error};
compute_unmergable_token_pairs();
build_error_parse_state();
allow_any_conflict = true;
processing_recovery_states = true;
build_error_parse_state(error_state_id);
process_part_state_queue();
allow_any_conflict = false;
mark_fragile_actions();
remove_duplicate_parse_states();
return { parse_table, CompileError::none() };
return {parse_table, CompileError::none()};
}
private:
@ -107,7 +95,7 @@ class ParseTableBuilder {
return CompileError::none();
}
void build_error_parse_state() {
void build_error_parse_state(ParseStateId state_id) {
ParseState error_state;
for (unsigned i = 0; i < lexical_grammar.variables.size(); i++) {
@ -142,7 +130,7 @@ class ParseTableBuilder {
}
error_state.terminal_entries[END_OF_INPUT()].actions.push_back(ParseAction::Recover(0));
parse_table.states[0] = error_state;
parse_table.states[state_id] = error_state;
}
void add_out_of_context_parse_state(ParseState *error_state,
@ -198,7 +186,7 @@ class ParseTableBuilder {
parse_table.add_terminal_action(state_id, lookahead, action);
} else {
ParseAction &existing_action = entry.actions[0];
if (existing_action.type == ParseActionTypeAccept || allow_any_conflict) {
if (existing_action.type == ParseActionTypeAccept || processing_recovery_states) {
entry.actions.push_back(action);
} else {
int existing_precedence = existing_action.precedence();
@ -241,9 +229,10 @@ class ParseTableBuilder {
ParseState &state = parse_table.states[state_id];
bool had_existing_action = !state.terminal_entries[lookahead].actions.empty();
parse_table.add_terminal_action(state_id, lookahead, ParseAction::Shift(next_state_id));
if (!allow_any_conflict) {
if (had_existing_action)
if (!processing_recovery_states) {
if (had_existing_action) {
lookaheads_with_conflicts.insert(lookahead);
}
recovery_states[lookahead].add(next_item_set);
}
}
@ -254,8 +243,9 @@ class ParseTableBuilder {
ParseItemSet &next_item_set = pair.second;
ParseStateId next_state = add_parse_state(next_item_set);
parse_table.set_nonterminal_action(state_id, lookahead, next_state);
if (!allow_any_conflict)
if (!processing_recovery_states) {
recovery_states[Symbol::non_terminal(lookahead)].add(next_item_set);
}
}
for (Symbol lookahead : lookaheads_with_conflicts) {
@ -267,7 +257,7 @@ class ParseTableBuilder {
ParseState &state = parse_table.states[state_id];
for (const Symbol &extra_symbol : grammar.extra_tokens) {
if (!state.terminal_entries.count(extra_symbol) ||
state.has_shift_action() || allow_any_conflict) {
state.has_shift_action() || processing_recovery_states) {
parse_table.add_terminal_action(state_id, extra_symbol, shift_extra);
}
}