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Restructure parse state merging logic

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* Remove remnants of templatized remove_duplicate_states function
* Rename recovery_tokens function to get_compatible_tokens and augment it
  also compute pairs of tokens which could potentially be incompatible
This commit is contained in:
Max Brunsfeld 2017-02-26 12:23:35 -08:00
parent 8d3b72e1d9
commit 3c8e6f9987
13 changed files with 274 additions and 252 deletions
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54
src/compiler/parse_table.cc
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@ -201,58 +201,4 @@ void ParseTable::set_nonterminal_action(ParseStateId state_id,
states[state_id].nonterminal_entries[lookahead] = next_state_id;
}
static bool has_entry(const ParseState &state, const ParseTableEntry &entry) {
for (const auto &pair : state.terminal_entries)
if (pair.second == entry)
return true;
return false;
}
bool ParseTable::merge_state(size_t i, size_t j) {
ParseState &state = states[i];
ParseState &other = states[j];
if (state.nonterminal_entries != other.nonterminal_entries)
return false;
for (auto &entry : state.terminal_entries) {
Symbol lookahead = entry.first;
const vector<ParseAction> &actions = entry.second.actions;
const auto &other_entry = other.terminal_entries.find(lookahead);
if (other_entry == other.terminal_entries.end()) {
if (mergeable_symbols.count(lookahead) == 0 && !lookahead.is_built_in())
return false;
if (actions.back().type != ParseActionTypeReduce)
return false;
if (!has_entry(other, entry.second))
return false;
} else if (entry.second != other_entry->second) {
return false;
}
}
set<Symbol> symbols_to_merge;
for (auto &entry : other.terminal_entries) {
Symbol lookahead = entry.first;
const vector<ParseAction> &actions = entry.second.actions;
if (!state.terminal_entries.count(lookahead)) {
if (mergeable_symbols.count(lookahead) == 0 && !lookahead.is_built_in())
return false;
if (actions.back().type != ParseActionTypeReduce)
return false;
if (!has_entry(state, entry.second))
return false;
symbols_to_merge.insert(lookahead);
}
}
for (const Symbol &lookahead : symbols_to_merge)
state.terminal_entries[lookahead] = other.terminal_entries.find(lookahead)->second;
return true;
}
} // namespace tree_sitter