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🎨 merge_parse_state

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This commit is contained in:
Max Brunsfeld 2017-07-10 15:01:09 -07:00
parent 43d347c225
commit 68c3ba1b8b
1 changed files with 23 additions and 24 deletions
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47
src/compiler/build_tables/build_parse_table.cc
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@ -413,49 +413,48 @@ class ParseTableBuilder {
}
}
static bool has_entry(const ParseState &state, const ParseTableEntry &entry) {
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 i, size_t j) {
ParseState &state = parse_table.states[i];
ParseState &other = parse_table.states[j];
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;
if (state.nonterminal_entries != other.nonterminal_entries) return false;
set<Symbol> symbols_to_merge;
for (auto &left_entry : left_state.terminal_entries) {
Symbol lookahead = left_entry.first;
for (auto &entry : state.terminal_entries) {
Symbol lookahead = entry.first;
const auto &other_entry = other.terminal_entries.find(lookahead);
if (other_entry == other.terminal_entries.end()) {
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 (entry.second.actions.back().type != ParseActionTypeReduce) return false;
if (!has_entry(other, entry.second)) 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_index[lookahead.index]) {
if (other.terminal_entries.count(incompatible_token)) return false;
if (right_state.terminal_entries.count(incompatible_token)) return false;
}
}
} else if (entry.second != other_entry->second) {
return false;
} else {
if (right_entry->second.actions != left_entry.second.actions) return false;
}
}
set<Symbol> symbols_to_merge;
for (auto &right_entry : right_state.terminal_entries) {
Symbol lookahead = right_entry.first;
for (auto &entry : other.terminal_entries) {
Symbol lookahead = entry.first;
if (!state.terminal_entries.count(lookahead)) {
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 (entry.second.actions.back().type != ParseActionTypeReduce) return false;
if (!has_entry(state, entry.second)) 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_index[lookahead.index]) {
if (state.terminal_entries.count(incompatible_token)) return false;
if (left_state.terminal_entries.count(incompatible_token)) return false;
}
}
@ -464,7 +463,7 @@ class ParseTableBuilder {
}
for (const Symbol &lookahead : symbols_to_merge) {
state.terminal_entries[lookahead] = other.terminal_entries.find(lookahead)->second;
left_state.terminal_entries[lookahead] = right_state.terminal_entries[lookahead];
}
return true;