tree-sitter/src/compiler/build_tables/build_lex_table.cc

124 lines
5.1 KiB
C++

#include "compiler/build_tables/build_tables.h"
#include <string>
#include <utility>
#include <map>
#include <set>
#include <unordered_map>
#include "compiler/prepared_grammar.h"
#include "compiler/rules/built_in_symbols.h"
#include "compiler/rules/metadata.h"
#include "compiler/rules/repeat.h"
#include "compiler/rules/blank.h"
#include "compiler/rules/seq.h"
#include "compiler/build_tables/lex_conflict_manager.h"
#include "compiler/build_tables/lex_item.h"
#include "compiler/build_tables/item_set_transitions.h"
namespace tree_sitter {
using std::string;
using std::map;
using std::unordered_map;
using std::set;
using std::make_shared;
using rules::Symbol;
using rules::CharacterSet;
namespace build_tables {
class LexTableBuilder {
const PreparedGrammar lex_grammar;
ParseTable *parse_table;
LexConflictManager conflict_manager;
unordered_map<const LexItemSet, LexStateId> lex_state_ids;
LexTable lex_table;
LexItemSet build_lex_item_set(const set<Symbol> &symbols) {
LexItemSet result;
for (const auto &symbol : symbols) {
if (symbol == rules::ERROR())
continue;
else if (symbol == rules::END_OF_INPUT())
result.insert(LexItem(symbol, after_separators(CharacterSet({ 0 }).copy())));
else if (symbol.is_token())
result.insert(LexItem(symbol, after_separators(lex_grammar.rule(symbol))));
}
return result;
}
LexStateId add_lex_state(const LexItemSet &item_set) {
auto pair = lex_state_ids.find(item_set);
if (pair == lex_state_ids.end()) {
LexStateId state_id = lex_table.add_state();
lex_state_ids[item_set] = state_id;
add_advance_actions(item_set, state_id);
add_accept_token_actions(item_set, state_id);
add_token_start(item_set, state_id);
return state_id;
} else {
return pair->second;
}
}
void add_error_lex_state() {
LexItemSet item_set = build_lex_item_set(parse_table->symbols);
add_advance_actions(item_set, LexTable::ERROR_STATE_ID);
add_accept_token_actions(item_set, LexTable::ERROR_STATE_ID);
}
void add_advance_actions(const LexItemSet &item_set, LexStateId state_id) {
auto transitions = char_transitions(item_set, lex_grammar);
for (const auto &transition : transitions) {
CharacterSet rule = transition.first;
LexItemSet new_item_set = transition.second;
LexStateId new_state_id = add_lex_state(new_item_set);
lex_table.add_action(state_id, rule, LexAction::Advance(new_state_id));
}
}
void add_accept_token_actions(const LexItemSet &item_set, LexStateId state_id) {
for (const LexItem &item : item_set) {
if (item.is_done()) {
auto current_action = lex_table.state(state_id).default_action;
auto new_action = LexAction::Accept(item.lhs, item.precedence());
if (conflict_manager.resolve_lex_action(current_action, new_action))
lex_table.add_default_action(state_id, new_action);
}
}
}
void add_token_start(const LexItemSet &item_set, LexStateId state_id) {
for (const auto &item : item_set)
if (item.is_token_start())
lex_table.state(state_id).is_token_start = true;
}
rules::rule_ptr after_separators(rules::rule_ptr rule) {
return rules::Seq::Build({
make_shared<rules::Repeat>(CharacterSet({ ' ', '\t', '\n', '\r' }).copy()),
make_shared<rules::Metadata>(make_shared<rules::Blank>(), map<rules::MetadataKey, int>({
{rules::START_TOKEN, 1},
})),
rule
});
}
public:
LexTableBuilder(ParseTable *parse_table, const PreparedGrammar &lex_grammar) :
lex_grammar(lex_grammar),
parse_table(parse_table),
conflict_manager(LexConflictManager(lex_grammar)) {}
LexTable build() {
for (auto &parse_state : parse_table->states) {
LexItemSet item_set = build_lex_item_set(parse_state.expected_inputs());
parse_state.lex_state_id = add_lex_state(item_set);
}
add_error_lex_state();
return lex_table;
}
};
LexTable build_lex_table(ParseTable *parse_table, const PreparedGrammar &lex_grammar) {
return LexTableBuilder(parse_table, lex_grammar).build();
}
}
}