821 lines
29 KiB
C++
821 lines
29 KiB
C++
#include "compiler/build_tables/parse_table_builder.h"
|
|
#include <algorithm>
|
|
#include <map>
|
|
#include <set>
|
|
#include <deque>
|
|
#include <string>
|
|
#include <unordered_map>
|
|
#include <utility>
|
|
#include "compiler/parse_table.h"
|
|
#include "compiler/build_tables/parse_item.h"
|
|
#include "compiler/build_tables/parse_item_set_builder.h"
|
|
#include "compiler/lexical_grammar.h"
|
|
#include "compiler/syntax_grammar.h"
|
|
#include "compiler/rule.h"
|
|
#include "compiler/build_tables/lex_table_builder.h"
|
|
|
|
namespace tree_sitter {
|
|
namespace build_tables {
|
|
|
|
using std::deque;
|
|
using std::find;
|
|
using std::pair;
|
|
using std::vector;
|
|
using std::set;
|
|
using std::map;
|
|
using std::move;
|
|
using std::string;
|
|
using std::to_string;
|
|
using std::unique_ptr;
|
|
using std::unordered_map;
|
|
using rules::Associativity;
|
|
using rules::Symbol;
|
|
using rules::END_OF_INPUT;
|
|
|
|
using SymbolSequence = vector<Symbol>;
|
|
|
|
struct ParseStateQueueEntry {
|
|
SymbolSequence preceding_symbols;
|
|
ParseItemSet item_set;
|
|
ParseStateId state_id;
|
|
};
|
|
|
|
class ParseTableBuilderImpl : public ParseTableBuilder {
|
|
const SyntaxGrammar grammar;
|
|
const LexicalGrammar lexical_grammar;
|
|
unordered_map<Symbol, ParseItemSet> recovery_item_sets_by_lookahead;
|
|
unordered_map<ParseItemSet, ParseStateId> state_ids_by_item_set;
|
|
vector<const ParseItemSet *> item_sets_by_state_id;
|
|
deque<ParseStateQueueEntry> parse_state_queue;
|
|
ParseTable parse_table;
|
|
ParseItemSetBuilder item_set_builder;
|
|
LexTableBuilder *lex_table_builder;
|
|
set<ParseAction> fragile_reductions;
|
|
vector<set<Symbol>> incompatible_tokens_by_token_index;
|
|
vector<set<Symbol::Index>> following_tokens_by_token_index;
|
|
bool processing_recovery_states;
|
|
|
|
public:
|
|
ParseTableBuilderImpl(
|
|
const SyntaxGrammar &syntax_grammar,
|
|
const LexicalGrammar &lexical_grammar,
|
|
LexTableBuilder *lex_table_builder
|
|
) : grammar(syntax_grammar),
|
|
lexical_grammar(lexical_grammar),
|
|
item_set_builder(syntax_grammar, lexical_grammar),
|
|
lex_table_builder(lex_table_builder),
|
|
incompatible_tokens_by_token_index(lexical_grammar.variables.size()),
|
|
following_tokens_by_token_index(lexical_grammar.variables.size()),
|
|
processing_recovery_states(false) {}
|
|
|
|
pair<ParseTable, CompileError> build() {
|
|
// Ensure that the empty rename sequence has index 0.
|
|
parse_table.alias_sequences.push_back({});
|
|
|
|
// Ensure that the error state has index 0.
|
|
ParseStateId error_state_id = add_parse_state({}, ParseItemSet{});
|
|
|
|
// Add the starting state.
|
|
Symbol start_symbol = grammar.variables.empty() ?
|
|
Symbol::terminal(0) :
|
|
Symbol::non_terminal(0);
|
|
|
|
Production start_production({{start_symbol, 0, rules::AssociativityNone, rules::Alias{}}}, 0);
|
|
|
|
add_parse_state({}, ParseItemSet{{
|
|
{
|
|
ParseItem(rules::START(), start_production, 0),
|
|
LookaheadSet({END_OF_INPUT()}),
|
|
},
|
|
}});
|
|
|
|
CompileError error = process_part_state_queue();
|
|
if (error) return {parse_table, error};
|
|
|
|
compute_unmergable_token_pairs();
|
|
|
|
processing_recovery_states = true;
|
|
build_error_parse_state(error_state_id);
|
|
process_part_state_queue();
|
|
|
|
mark_fragile_actions();
|
|
remove_duplicate_parse_states();
|
|
return {parse_table, CompileError::none()};
|
|
}
|
|
|
|
private:
|
|
CompileError process_part_state_queue() {
|
|
while (!parse_state_queue.empty()) {
|
|
auto entry = parse_state_queue.front();
|
|
parse_state_queue.pop_front();
|
|
|
|
item_set_builder.apply_transitive_closure(&entry.item_set);
|
|
string conflict = add_actions(
|
|
move(entry.preceding_symbols),
|
|
move(entry.item_set),
|
|
entry.state_id
|
|
);
|
|
|
|
if (!conflict.empty()) {
|
|
return CompileError(TSCompileErrorTypeParseConflict, conflict);
|
|
}
|
|
}
|
|
|
|
return CompileError::none();
|
|
}
|
|
|
|
void build_error_parse_state(ParseStateId state_id) {
|
|
ParseState error_state;
|
|
|
|
for (unsigned i = 0; i < lexical_grammar.variables.size(); i++) {
|
|
Symbol token = Symbol::terminal(i);
|
|
bool has_non_reciprocal_conflict = false;
|
|
|
|
for (Symbol incompatible_token : incompatible_tokens_by_token_index[i]) {
|
|
if (incompatible_token.is_terminal() &&
|
|
!incompatible_tokens_by_token_index[incompatible_token.index].count(token)) {
|
|
has_non_reciprocal_conflict = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!has_non_reciprocal_conflict) {
|
|
add_out_of_context_parse_state(&error_state, Symbol::terminal(i));
|
|
}
|
|
}
|
|
|
|
for (const Symbol &symbol : grammar.extra_tokens) {
|
|
if (!error_state.terminal_entries.count(symbol)) {
|
|
error_state.terminal_entries[symbol].actions.push_back(ParseAction::ShiftExtra());
|
|
}
|
|
}
|
|
|
|
for (size_t i = 0; i < grammar.external_tokens.size(); i++) {
|
|
add_out_of_context_parse_state(&error_state, Symbol::external(i));
|
|
}
|
|
|
|
for (size_t i = 0; i < grammar.variables.size(); i++) {
|
|
add_out_of_context_parse_state(&error_state, Symbol::non_terminal(i));
|
|
}
|
|
|
|
error_state.terminal_entries[END_OF_INPUT()].actions.push_back(ParseAction::Recover(0));
|
|
parse_table.states[state_id] = error_state;
|
|
}
|
|
|
|
void add_out_of_context_parse_state(ParseState *error_state,
|
|
const rules::Symbol &symbol) {
|
|
const ParseItemSet &item_set = recovery_item_sets_by_lookahead[symbol];
|
|
if (!item_set.entries.empty()) {
|
|
ParseStateId state = add_parse_state({}, item_set);
|
|
if (symbol.is_non_terminal()) {
|
|
error_state->nonterminal_entries[symbol.index] = state;
|
|
} else {
|
|
error_state->terminal_entries[symbol].actions.assign({ ParseAction::Recover(state) });
|
|
}
|
|
}
|
|
}
|
|
|
|
ParseStateId add_parse_state(SymbolSequence &&preceding_symbols, const ParseItemSet &item_set) {
|
|
ParseStateId new_state_id = parse_table.states.size();
|
|
auto insertion = state_ids_by_item_set.insert({move(item_set), new_state_id});
|
|
if (insertion.second) {
|
|
item_sets_by_state_id.push_back(&insertion.first->first);
|
|
parse_table.states.push_back(ParseState());
|
|
parse_state_queue.push_back({
|
|
move(preceding_symbols),
|
|
insertion.first->first,
|
|
new_state_id
|
|
});
|
|
return new_state_id;
|
|
} else {
|
|
return insertion.first->second;
|
|
}
|
|
}
|
|
|
|
string add_actions(SymbolSequence &&sequence, ParseItemSet &&item_set, ParseStateId state_id) {
|
|
map<Symbol, ParseItemSet> terminal_successors;
|
|
map<Symbol::Index, ParseItemSet> nonterminal_successors;
|
|
set<Symbol> lookaheads_with_conflicts;
|
|
|
|
for (const auto &pair : item_set.entries) {
|
|
const ParseItem &item = pair.first;
|
|
const LookaheadSet &lookahead_symbols = pair.second;
|
|
|
|
// If the item is finished, immediately add a Reduce or Accept action to
|
|
// the parse table for each of its lookahead terminals.
|
|
if (item.is_done()) {
|
|
ParseAction action = item.lhs() == rules::START() ?
|
|
ParseAction::Accept() :
|
|
ParseAction::Reduce(
|
|
item.lhs(),
|
|
item.step_index,
|
|
item.precedence(),
|
|
item.production->dynamic_precedence,
|
|
item.associativity(),
|
|
get_alias_sequence_id(*item.production)
|
|
);
|
|
|
|
lookahead_symbols.for_each([&](Symbol lookahead) {
|
|
ParseTableEntry &entry = parse_table.states[state_id].terminal_entries[lookahead];
|
|
|
|
// Only add the highest-precedence Reduce actions to the parse table.
|
|
// If other lower-precedence actions are possible, ignore them.
|
|
if (entry.actions.empty()) {
|
|
parse_table.add_terminal_action(state_id, lookahead, action);
|
|
} else {
|
|
ParseAction &existing_action = entry.actions[0];
|
|
if (existing_action.type == ParseActionTypeAccept || processing_recovery_states) {
|
|
entry.actions.push_back(action);
|
|
} else {
|
|
if (action.precedence > existing_action.precedence) {
|
|
for (const ParseAction &old_action : entry.actions) {
|
|
fragile_reductions.insert(old_action);
|
|
}
|
|
entry.actions.assign({action});
|
|
lookaheads_with_conflicts.erase(lookahead);
|
|
} else if (action.precedence == existing_action.precedence) {
|
|
entry.actions.push_back(action);
|
|
lookaheads_with_conflicts.insert(lookahead);
|
|
} else {
|
|
fragile_reductions.insert(action);
|
|
}
|
|
}
|
|
}
|
|
});
|
|
|
|
// If the item is unfinished, create a new item by advancing one symbol.
|
|
// Add that new item to a successor item set.
|
|
} else {
|
|
Symbol symbol = item.production->at(item.step_index).symbol;
|
|
ParseItem new_item(item.lhs(), *item.production, item.step_index + 1);
|
|
|
|
if (symbol.is_non_terminal()) {
|
|
nonterminal_successors[symbol.index].entries[new_item] = lookahead_symbols;
|
|
} else {
|
|
terminal_successors[symbol].entries[new_item] = lookahead_symbols;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Add a Shift action for each possible successor state. Shift actions for
|
|
// terminal lookaheads can conflict with Reduce actions added previously.
|
|
for (auto &pair : terminal_successors) {
|
|
Symbol lookahead = pair.first;
|
|
ParseItemSet &next_item_set = pair.second;
|
|
ParseStateId next_state_id = add_parse_state(append_symbol(sequence, lookahead), next_item_set);
|
|
|
|
if (!processing_recovery_states) {
|
|
recovery_item_sets_by_lookahead[lookahead].add(next_item_set);
|
|
if (!parse_table.states[state_id].terminal_entries[lookahead].actions.empty()) {
|
|
lookaheads_with_conflicts.insert(lookahead);
|
|
}
|
|
}
|
|
|
|
parse_table.add_terminal_action(state_id, lookahead, ParseAction::Shift(next_state_id));
|
|
}
|
|
|
|
// Add a Shift action for each non-terminal transition.
|
|
for (auto &pair : nonterminal_successors) {
|
|
Symbol lookahead = Symbol::non_terminal(pair.first);
|
|
ParseItemSet &next_item_set = pair.second;
|
|
ParseStateId next_state_id = add_parse_state(append_symbol(sequence, lookahead), next_item_set);
|
|
parse_table.set_nonterminal_action(state_id, lookahead.index, next_state_id);
|
|
if (!processing_recovery_states) {
|
|
recovery_item_sets_by_lookahead[lookahead].add(next_item_set);
|
|
}
|
|
}
|
|
|
|
for (Symbol lookahead : lookaheads_with_conflicts) {
|
|
string conflict = handle_conflict(lookahead, item_set, sequence, state_id);
|
|
if (!conflict.empty()) return conflict;
|
|
}
|
|
|
|
ParseAction shift_extra = ParseAction::ShiftExtra();
|
|
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() || processing_recovery_states) {
|
|
parse_table.add_terminal_action(state_id, extra_symbol, shift_extra);
|
|
}
|
|
}
|
|
|
|
return "";
|
|
}
|
|
|
|
void mark_fragile_actions() {
|
|
for (ParseState &state : parse_table.states) {
|
|
for (auto &entry : state.terminal_entries) {
|
|
auto &actions = entry.second.actions;
|
|
|
|
for (ParseAction &action : actions) {
|
|
if (action.type == ParseActionTypeReduce) {
|
|
if (action_is_fragile(action)) {
|
|
action.fragile = true;
|
|
}
|
|
action.precedence = 0;
|
|
action.associativity = rules::AssociativityNone;
|
|
}
|
|
}
|
|
|
|
for (auto i = actions.begin(); i != actions.end();) {
|
|
bool erased = false;
|
|
for (auto j = actions.begin(); j != i; j++) {
|
|
if (*j == *i) {
|
|
actions.erase(i);
|
|
erased = true;
|
|
break;
|
|
}
|
|
}
|
|
if (!erased) {
|
|
++i;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
bool action_is_fragile(const ParseAction &action) {
|
|
for (auto &fragile_action : fragile_reductions) {
|
|
if (fragile_action.symbol == action.symbol &&
|
|
fragile_action.consumed_symbol_count == action.consumed_symbol_count &&
|
|
fragile_action.dynamic_precedence == action.dynamic_precedence) {
|
|
if (fragile_action.precedence > action.precedence) {
|
|
return true;
|
|
}
|
|
|
|
if (fragile_action.precedence == action.precedence &&
|
|
(fragile_action.associativity == action.associativity ||
|
|
fragile_action.associativity == rules::AssociativityLeft ||
|
|
action.associativity == rules::AssociativityRight)) {
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
void compute_unmergable_token_pairs() {
|
|
for (unsigned i = 0, n = lexical_grammar.variables.size(); i < n; i++) {
|
|
Symbol token = Symbol::terminal(i);
|
|
auto &incompatible_indices = incompatible_tokens_by_token_index[i];
|
|
|
|
for (unsigned j = 0; j < n; j++) {
|
|
if (i == j) continue;
|
|
if (lex_table_builder->detect_conflict(i, j, following_tokens_by_token_index)) {
|
|
incompatible_indices.insert(Symbol::terminal(j));
|
|
}
|
|
}
|
|
|
|
for (const ExternalToken &external_token : grammar.external_tokens) {
|
|
if (external_token.corresponding_internal_token == token) {
|
|
for (unsigned j = 0; j < grammar.external_tokens.size(); j++) {
|
|
incompatible_indices.insert(Symbol::external(j));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void remove_duplicate_parse_states() {
|
|
unordered_map<size_t, set<ParseStateId>> state_indices_by_signature;
|
|
|
|
for (auto &pair : state_ids_by_item_set) {
|
|
const ParseItemSet &item_set = pair.first;
|
|
ParseStateId state_id = pair.second;
|
|
state_indices_by_signature[item_set.unfinished_item_signature()].insert(state_id);
|
|
}
|
|
|
|
set<ParseStateId> deleted_states;
|
|
|
|
while (true) {
|
|
map<ParseStateId, ParseStateId> state_replacements;
|
|
|
|
for (auto &pair : state_indices_by_signature) {
|
|
auto &state_indices = pair.second;
|
|
|
|
for (auto i = state_indices.begin(), end = state_indices.end(); i != end;) {
|
|
for (ParseStateId j : state_indices) {
|
|
if (j == *i) {
|
|
++i;
|
|
break;
|
|
}
|
|
if (!state_replacements.count(j) && merge_parse_state(j, *i)) {
|
|
state_replacements.insert({*i, j});
|
|
deleted_states.insert(*i);
|
|
i = state_indices.erase(i);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (state_replacements.empty()) break;
|
|
|
|
for (ParseStateId i = 0, n = parse_table.states.size(); i < n; i++) {
|
|
if (!state_replacements.count(i)) {
|
|
ParseState &state = parse_table.states[i];
|
|
state.each_referenced_state([&state_replacements](ParseStateId *state_index) {
|
|
auto replacement = state_replacements.find(*state_index);
|
|
if (replacement != state_replacements.end()) {
|
|
*state_index = replacement->second;
|
|
}
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
vector<ParseStateId> new_state_ids(parse_table.states.size());
|
|
size_t deleted_state_count = 0;
|
|
auto deleted_state_iter = deleted_states.begin();
|
|
for (ParseStateId i = 0; i < new_state_ids.size(); i++) {
|
|
while (deleted_state_iter != deleted_states.end() && *deleted_state_iter < i) {
|
|
deleted_state_count++;
|
|
deleted_state_iter++;
|
|
}
|
|
new_state_ids[i] = i - deleted_state_count;
|
|
}
|
|
|
|
ParseStateId original_state_index = 0;
|
|
auto iter = parse_table.states.begin();
|
|
while (iter != parse_table.states.end()) {
|
|
if (deleted_states.count(original_state_index)) {
|
|
iter = parse_table.states.erase(iter);
|
|
} else {
|
|
ParseState &state = *iter;
|
|
state.each_referenced_state([&new_state_ids](ParseStateId *state_index) {
|
|
*state_index = new_state_ids[*state_index];
|
|
});
|
|
++iter;
|
|
}
|
|
original_state_index++;
|
|
}
|
|
}
|
|
|
|
static bool has_actions(const ParseState &state, const ParseTableEntry &entry) {
|
|
for (const auto &pair : state.terminal_entries)
|
|
if (pair.second.actions == entry.actions)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
bool merge_parse_state(size_t left_index, size_t right_index) {
|
|
ParseState &left_state = parse_table.states[left_index];
|
|
ParseState &right_state = parse_table.states[right_index];
|
|
if (left_state.nonterminal_entries != right_state.nonterminal_entries) return false;
|
|
|
|
set<Symbol> symbols_to_merge;
|
|
for (auto &left_entry : left_state.terminal_entries) {
|
|
Symbol lookahead = left_entry.first;
|
|
|
|
const auto &right_entry = right_state.terminal_entries.find(lookahead);
|
|
if (right_entry == right_state.terminal_entries.end()) {
|
|
if (lookahead.is_external()) return false;
|
|
if (left_entry.second.actions.back().type != ParseActionTypeReduce) return false;
|
|
if (!has_actions(right_state, left_entry.second)) return false;
|
|
if (!lookahead.is_built_in()) {
|
|
for (const Symbol &incompatible_token : incompatible_tokens_by_token_index[lookahead.index]) {
|
|
if (right_state.terminal_entries.count(incompatible_token)) return false;
|
|
}
|
|
}
|
|
} else {
|
|
if (right_entry->second.actions != left_entry.second.actions) return false;
|
|
}
|
|
}
|
|
|
|
for (auto &right_entry : right_state.terminal_entries) {
|
|
Symbol lookahead = right_entry.first;
|
|
|
|
const auto &left_entry = left_state.terminal_entries.find(lookahead);
|
|
if (left_entry == left_state.terminal_entries.end()) {
|
|
if (lookahead.is_external()) return false;
|
|
if (right_entry.second.actions.back().type != ParseActionTypeReduce) return false;
|
|
if (!has_actions(left_state, right_entry.second)) return false;
|
|
if (!lookahead.is_built_in()) {
|
|
for (const Symbol &incompatible_token : incompatible_tokens_by_token_index[lookahead.index]) {
|
|
if (left_state.terminal_entries.count(incompatible_token)) return false;
|
|
}
|
|
}
|
|
|
|
symbols_to_merge.insert(lookahead);
|
|
}
|
|
}
|
|
|
|
for (const Symbol &lookahead : symbols_to_merge) {
|
|
left_state.terminal_entries[lookahead] = right_state.terminal_entries[lookahead];
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
string handle_conflict(Symbol lookahead, const ParseItemSet &item_set,
|
|
const SymbolSequence &preceding_symbols, ParseStateId state_id) {
|
|
ParseTableEntry &entry = parse_table.states[state_id].terminal_entries[lookahead];
|
|
bool considered_associativity = false;
|
|
int reduction_precedence = entry.actions.front().precedence;
|
|
|
|
PrecedenceRange shift_precedence;
|
|
set<ParseItem> conflicting_items;
|
|
for (auto &pair : item_set.entries) {
|
|
const ParseItem &item = pair.first;
|
|
if (item.is_done()) {
|
|
if (pair.second.contains(lookahead)) {
|
|
conflicting_items.insert(item);
|
|
}
|
|
} else if (item.step_index > 0) {
|
|
LookaheadSet first_set = item_set_builder.get_first_set(item.next_symbol());
|
|
if (first_set.contains(lookahead)) {
|
|
shift_precedence.add(item.production->at(item.step_index - 1).precedence);
|
|
conflicting_items.insert(item);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (entry.actions.back().type == ParseActionTypeShift) {
|
|
|
|
// If the shift action has higher precedence, prefer it over any of the
|
|
// reduce actions.
|
|
if (shift_precedence.min > reduction_precedence ||
|
|
(shift_precedence.min == reduction_precedence &&
|
|
shift_precedence.max > reduction_precedence)) {
|
|
entry.actions.assign({entry.actions.back()});
|
|
for (const ParseAction &action : entry.actions) {
|
|
if (action.type == ParseActionTypeReduce) {
|
|
fragile_reductions.insert(action);
|
|
}
|
|
}
|
|
}
|
|
|
|
// If the shift action has lower precedence, prefer the reduce actions.
|
|
else if (shift_precedence.max < reduction_precedence ||
|
|
(shift_precedence.max == reduction_precedence &&
|
|
shift_precedence.min < reduction_precedence)) {
|
|
entry.actions.pop_back();
|
|
for (auto item_iter = conflicting_items.begin(); item_iter != conflicting_items.end();) {
|
|
if (item_iter->is_done()) {
|
|
++item_iter;
|
|
} else {
|
|
item_iter = conflicting_items.erase(item_iter);
|
|
}
|
|
}
|
|
}
|
|
|
|
// If the shift action has the same precedence as the reduce actions,
|
|
// consider the reduce actions' associativity. If they are all left
|
|
// associative, prefer the reduce actions. If they are all right
|
|
// associative, prefer the shift.
|
|
else if (shift_precedence.min == reduction_precedence &&
|
|
shift_precedence.max == reduction_precedence) {
|
|
considered_associativity = true;
|
|
bool has_non_associative_reductions = false;
|
|
bool has_left_associative_reductions = false;
|
|
bool has_right_associative_reductions = false;
|
|
for (const ParseAction &action : entry.actions) {
|
|
if (action.type != ParseActionTypeReduce) break;
|
|
switch (action.associativity) {
|
|
case rules::AssociativityLeft:
|
|
has_left_associative_reductions = true;
|
|
break;
|
|
case rules::AssociativityRight:
|
|
has_right_associative_reductions = true;
|
|
break;
|
|
default:
|
|
has_non_associative_reductions = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!has_non_associative_reductions) {
|
|
if (has_right_associative_reductions && !has_left_associative_reductions) {
|
|
for (const ParseAction &action : entry.actions) {
|
|
if (action.type == ParseActionTypeReduce) {
|
|
fragile_reductions.insert(action);
|
|
}
|
|
}
|
|
entry.actions.assign({entry.actions.back()});
|
|
} else if (has_left_associative_reductions && !has_right_associative_reductions) {
|
|
entry.actions.pop_back();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (entry.actions.size() == 1) return "";
|
|
|
|
for (const ParseAction &action : entry.actions) {
|
|
if (action.type == ParseActionTypeReduce) {
|
|
fragile_reductions.insert(action);
|
|
}
|
|
}
|
|
|
|
set<Symbol> actual_conflict;
|
|
for (const ParseItem &item : conflicting_items) {
|
|
Symbol symbol = item.lhs();
|
|
if (grammar.variables[symbol.index].type == VariableTypeAuxiliary) {
|
|
ParseStateId preceding_state_id = 1;
|
|
for (auto &preceding_symbol : preceding_symbols) {
|
|
ParseState &preceding_state = parse_table.states[preceding_state_id];
|
|
if (preceding_state.nonterminal_entries.count(symbol.index)) break;
|
|
preceding_state_id = preceding_symbol.is_terminal() ?
|
|
preceding_state.terminal_entries[preceding_symbol].actions.back().state_index :
|
|
preceding_state.nonterminal_entries[preceding_symbol.index];
|
|
}
|
|
const ParseItemSet &preceding_item_set = *item_sets_by_state_id[preceding_state_id];
|
|
for (auto &preceding_entry : preceding_item_set.entries) {
|
|
if (preceding_entry.first.next_symbol() == symbol) {
|
|
actual_conflict.insert(preceding_entry.first.lhs());
|
|
}
|
|
}
|
|
} else {
|
|
actual_conflict.insert(symbol);
|
|
}
|
|
}
|
|
|
|
for (const auto &expected_conflict : grammar.expected_conflicts) {
|
|
if (expected_conflict == actual_conflict) return "";
|
|
}
|
|
|
|
string description = "Unresolved conflict for symbol sequence:\n\n";
|
|
for (auto &symbol : preceding_symbols) {
|
|
description += " " + symbol_name(symbol);
|
|
}
|
|
|
|
const string dot = "\xE2\x80\xA2";
|
|
const string ellipsis = "\xE2\x80\xA6";
|
|
|
|
description += " " + dot + " " + symbol_name(lookahead) + " " + ellipsis;
|
|
description += "\n\n";
|
|
description += "Possible interpretations:\n\n";
|
|
|
|
size_t interpretation_count = 1;
|
|
for (const ParseItem &item : conflicting_items) {
|
|
description += " " + to_string(interpretation_count++) + ":";
|
|
|
|
for (size_t i = 0; i < preceding_symbols.size() - item.step_index; i++) {
|
|
description += " " + symbol_name(preceding_symbols[i]);
|
|
}
|
|
|
|
description += " (" + symbol_name(item.lhs());
|
|
for (size_t i = 0; i < item.production->size(); i++) {
|
|
if (i == item.step_index) {
|
|
description += " " + dot;
|
|
}
|
|
description += " " + symbol_name(item.production->at(i).symbol);
|
|
}
|
|
description += ")";
|
|
|
|
if (item.is_done()) {
|
|
description += " " + dot + " " + symbol_name(lookahead) + " " + ellipsis;
|
|
}
|
|
|
|
description += "\n";
|
|
}
|
|
|
|
description += "\nPossible resolutions:\n\n";
|
|
|
|
size_t resolution_count = 1;
|
|
if (actual_conflict.size() > 1) {
|
|
if (entry.actions.back().type == ParseActionTypeShift) {
|
|
description += " " + to_string(resolution_count++) + ": ";
|
|
description += "Specify a higher precedence in";
|
|
bool is_first = true;
|
|
for (Symbol conflict_symbol : actual_conflict) {
|
|
for (const ParseItem &parse_item : conflicting_items) {
|
|
if (parse_item.lhs() == conflict_symbol && !parse_item.is_done()) {
|
|
if (!is_first) description += " and";
|
|
description += " `" + symbol_name(conflict_symbol) + "`";
|
|
is_first = false;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
description += " than in the other rules.\n";
|
|
}
|
|
|
|
for (const ParseAction &action : entry.actions) {
|
|
if (action.type == ParseActionTypeReduce) {
|
|
description += " " + to_string(resolution_count++) + ": ";
|
|
description += "Specify a higher precedence in `";
|
|
description += symbol_name(action.symbol);
|
|
description += "` than in the other rules.\n";
|
|
}
|
|
}
|
|
}
|
|
|
|
if (considered_associativity) {
|
|
description += " " + to_string(resolution_count++) + ": ";
|
|
description += "Specify a left or right associativity in";
|
|
bool is_first = true;
|
|
for (const ParseAction &action : entry.actions) {
|
|
if (action.type == ParseActionTypeReduce) {
|
|
if (!is_first) description += " and";
|
|
description += " `" + symbol_name(action.symbol) + "`";
|
|
is_first = false;
|
|
}
|
|
}
|
|
description += "\n";
|
|
}
|
|
|
|
description += " " + to_string(resolution_count++) + ": ";
|
|
description += "Add a conflict for these rules:";
|
|
for (Symbol conflict_symbol : actual_conflict) {
|
|
description += " `" + symbol_name(conflict_symbol) + "`";
|
|
}
|
|
description += "\n";
|
|
return description;
|
|
}
|
|
|
|
string symbol_name(const rules::Symbol &symbol) const {
|
|
if (symbol.is_built_in()) {
|
|
if (symbol == END_OF_INPUT())
|
|
return "END_OF_INPUT";
|
|
else
|
|
return "";
|
|
}
|
|
|
|
switch (symbol.type) {
|
|
case Symbol::Terminal: {
|
|
const LexicalVariable &variable = lexical_grammar.variables[symbol.index];
|
|
if (variable.type == VariableTypeNamed)
|
|
return variable.name;
|
|
else
|
|
return "'" + variable.name + "'";
|
|
}
|
|
case Symbol::NonTerminal: {
|
|
return grammar.variables[symbol.index].name;
|
|
}
|
|
case Symbol::External:
|
|
default: {
|
|
return grammar.external_tokens[symbol.index].name;
|
|
}
|
|
}
|
|
}
|
|
|
|
unsigned get_alias_sequence_id(const Production &production) {
|
|
bool has_alias = false;
|
|
AliasSequence alias_sequence;
|
|
for (unsigned i = 0, n = production.size(); i < n; i++) {
|
|
auto &step = production.at(i);
|
|
if (!step.alias.value.empty()) {
|
|
has_alias = true;
|
|
alias_sequence.resize(i + 1);
|
|
alias_sequence[i] = step.alias;
|
|
}
|
|
}
|
|
|
|
if (has_alias && production.size() > parse_table.max_alias_sequence_length) {
|
|
parse_table.max_alias_sequence_length = production.size();
|
|
}
|
|
|
|
auto begin = parse_table.alias_sequences.begin();
|
|
auto end = parse_table.alias_sequences.end();
|
|
auto iter = find(begin, end, alias_sequence);
|
|
if (iter != end) {
|
|
return iter - begin;
|
|
} else {
|
|
parse_table.alias_sequences.push_back(move(alias_sequence));
|
|
return parse_table.alias_sequences.size() - 1;
|
|
}
|
|
}
|
|
|
|
SymbolSequence append_symbol(const SymbolSequence &sequence, const Symbol &symbol) {
|
|
if (!sequence.empty()) {
|
|
const LookaheadSet &left_tokens = item_set_builder.get_last_set(sequence.back());
|
|
const LookaheadSet &right_tokens = item_set_builder.get_first_set(symbol);
|
|
|
|
if (!left_tokens.empty() && !right_tokens.empty()) {
|
|
left_tokens.for_each([&](Symbol left_symbol) {
|
|
if (left_symbol.is_terminal() && !left_symbol.is_built_in()) {
|
|
right_tokens.for_each([&](Symbol right_symbol) {
|
|
if (right_symbol.is_terminal() && !right_symbol.is_built_in()) {
|
|
following_tokens_by_token_index[left_symbol.index].insert(right_symbol.index);
|
|
}
|
|
});
|
|
}
|
|
});
|
|
}
|
|
}
|
|
|
|
SymbolSequence result(sequence.size() + 1);
|
|
result.assign(sequence.begin(), sequence.end());
|
|
result.push_back(symbol);
|
|
return result;
|
|
}
|
|
};
|
|
|
|
unique_ptr<ParseTableBuilder> ParseTableBuilder::create(
|
|
const SyntaxGrammar &syntax_grammar,
|
|
const LexicalGrammar &lexical_grammar,
|
|
LexTableBuilder *lex_table_builder
|
|
) {
|
|
return unique_ptr<ParseTableBuilder>(
|
|
new ParseTableBuilderImpl(syntax_grammar, lexical_grammar, lex_table_builder)
|
|
);
|
|
}
|
|
|
|
pair<ParseTable, CompileError> ParseTableBuilder::build() {
|
|
return static_cast<ParseTableBuilderImpl *>(this)->build();
|
|
}
|
|
|
|
} // namespace build_tables
|
|
} // namespace tree_sitter
|