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Avoid creating redundant auxiliary repeat rules

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This commit is contained in:
Max Brunsfeld 2015-04-16 17:42:22 -07:00
parent 9ef52ce2fb
commit e8db35af6b
3 changed files with 2227 additions and 2263 deletions
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20
src/compiler/prepare_grammar/expand_repeats.cc
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@ -28,18 +28,28 @@ using rules::Symbol;
class ExpandRepeats : public rules::IdentityRuleFn {
string rule_name;
vector<pair<const rule_ptr, Symbol>> existing_repeats;
rule_ptr expand_repeat(const Repeat *rule) {
for (auto pair : existing_repeats) {
if (pair.first->operator==(*rule))
return pair.second.copy();
}
rule_ptr apply_to(const Repeat *rule) {
rule_ptr inner_rule = apply(rule->content);
size_t index = aux_rules.size();
string helper_rule_name = rule_name + string("_repeat") + to_string(index);
rule_ptr repeat_symbol =
make_shared<Symbol>(offset + index, rules::SymbolOptionAuxiliary);
Symbol repeat_symbol(offset + index, rules::SymbolOptionAuxiliary);
existing_repeats.push_back({ rule->copy(), repeat_symbol });
aux_rules.push_back(
{ helper_rule_name,
Seq::build({ inner_rule, Choice::build({ repeat_symbol,
Seq::build({ inner_rule, Choice::build({ repeat_symbol.copy(),
make_shared<Blank>() }) }) });
return Choice::build({ repeat_symbol, make_shared<Blank>() });
return repeat_symbol.copy();
}
rule_ptr apply_to(const Repeat *rule) {
return Choice::build({ expand_repeat(rule), make_shared<Blank>() });
}
public: