120 lines
No EOL
5.2 KiB
C++
120 lines
No EOL
5.2 KiB
C++
#include "table_builder.h"
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#include "item_set.h"
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#include "rules.h"
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#include "grammar.h"
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using std::pair;
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using std::vector;
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namespace tree_sitter {
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namespace lr {
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static int NOT_FOUND = -1;
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class TableBuilder {
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const Grammar grammar;
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const Grammar lex_grammar;
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std::unordered_map<const ItemSet, size_t> parse_state_indices;
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std::unordered_map<const ItemSet, size_t> lex_state_indices;
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ParseTable parse_table;
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LexTable lex_table;
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long parse_state_index_for_item_set(const ItemSet &item_set) const {
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auto entry = parse_state_indices.find(item_set);
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return (entry == parse_state_indices.end()) ? NOT_FOUND : entry->second;
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}
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long lex_state_index_for_item_set(const ItemSet &item_set) const {
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auto entry = lex_state_indices.find(item_set);
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return (entry == lex_state_indices.end()) ? NOT_FOUND : entry->second;
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}
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void add_shift_actions(const ItemSet &item_set, size_t state_index) {
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auto x = item_set.sym_transitions(grammar);
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for (auto transition : x) {
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rules::Symbol symbol = *transition.first;
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ItemSet item_set = *transition.second;
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size_t new_state_index = add_parse_state(item_set);
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parse_table.add_action(state_index, symbol.name, ParseAction::Shift(new_state_index));
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}
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}
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void add_advance_actions(const ItemSet &item_set, size_t state_index) {
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for (auto transition : item_set.char_transitions(grammar)) {
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rules::Character rule = *transition.first;
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ItemSet item_set = *transition.second;
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size_t new_state_index = add_lex_state(item_set);
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lex_table.add_action(state_index, rule.value, LexAction::Advance(new_state_index));
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}
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}
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void add_accept_token_actions(const ItemSet &item_set, size_t state_index) {
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for (Item item : item_set) {
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if (item.is_done()) {
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lex_table.add_default_action(state_index, LexAction::Accept(item.rule_name));
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}
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}
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}
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void add_reduce_actions(const ItemSet &item_set, size_t state_index) {
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for (Item item : item_set) {
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if (item.is_done()) {
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if (item.rule_name == ParseTable::START) {
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parse_table.add_action(state_index, ParseTable::END_OF_INPUT, ParseAction::Accept());
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} else {
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parse_table.add_default_action(state_index, ParseAction::Reduce(item.rule_name, item.consumed_sym_count));
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}
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}
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}
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}
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size_t add_lex_state(const ItemSet &item_set) {
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auto state_index = lex_state_index_for_item_set(item_set);
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if (state_index == NOT_FOUND) {
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state_index = lex_table.add_state();
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lex_state_indices[item_set] = state_index;
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add_advance_actions(item_set, state_index);
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add_accept_token_actions(item_set, state_index);
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}
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return state_index;
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}
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ItemSet lex_item_set_for_parse_item_set(const ItemSet &parse_item_set) {
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vector<Item> items;
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for (rules::Symbol symbol : parse_item_set.next_terminal_symbols(grammar))
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items.push_back(Item::at_beginning_of_token(symbol.name, lex_grammar));
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return ItemSet(items);
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}
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size_t add_parse_state(const ItemSet &item_set) {
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auto state_index = parse_state_index_for_item_set(item_set);
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if (state_index == NOT_FOUND) {
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state_index = parse_table.add_state();
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parse_state_indices[item_set] = state_index;
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ItemSet lex_item_set = lex_item_set_for_parse_item_set(item_set);
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parse_table.states[state_index].lex_state_index = add_lex_state(lex_item_set);
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add_shift_actions(item_set, state_index);
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add_reduce_actions(item_set, state_index);
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}
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return state_index;
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}
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public:
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TableBuilder(const Grammar &grammar, const Grammar &lex_grammar) :
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grammar(grammar),
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lex_grammar(lex_grammar) {};
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pair<ParseTable, LexTable> build() {
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auto item = Item(ParseTable::START, rules::sym(grammar.start_rule_name), 0);
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auto item_set = ItemSet(item, grammar);
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add_parse_state(item_set);
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return pair<ParseTable, LexTable>(parse_table, lex_table);
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}
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};
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pair<ParseTable, LexTable> build_tables(const Grammar &grammar, const Grammar &lex_grammar) {
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return TableBuilder(grammar, lex_grammar).build();
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}
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}
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} |