Parsing [ pl/sql grammer] too slow with C++ target

[searocsun]

Background: I want to parser pl/sql with c ++target .

Grammar: https://github.com/antlr/grammars-v4/tree/master/plsql

results: ParseTree is too slow, about 3 ~4 seconds

int main(int , const char *) { std::string str; std::string str_rep = "TO_NUMBER()"; std::string str_where = "WHERE";

std::string tmp_str;
std::string tmp_str_col;

std::string::size_type position;

ANTLRInputStream input; 

PlSqlLexer lexer(&input);

CommonTokenStream tokens(&lexer);

PlSqlParser parser(&tokens);

std::cout << "Please enter PlSql sql string: " << std::endl;

while (std::getline(std::cin, str,'^')&&str != "q"){

    transform(str.begin(), str.end(), str.begin(), ::toupper);

    input.load(str);

    lexer.Lexer::setInputStream(&input);

    tokens.setTokenSource(&lexer);

    tokens.fill();

    /*
    for (auto token : tokens.getTokens()){
    std::cout << token->toString() << std::endl;
    }
    */

    parser.setInputStream(&tokens);

    tree::ParseTree* tree = parser.sql_script();

} }

Can someone tell me how to fix this problem?

Thanks

[Nic30]

Step 0: download intellij + antlr4 plugin and take look at what is slow in your grammar.

You should be able to see something like this:

You can sort by time and click on row to highlight the corresponding rule.

(Note that there are also other tools which does the same.)

[searocsun]

@Nic30 Thank you for your advice

[Nic30]

Actually, no, I did not gave you a good advice. You do have an embedded C++ in your code. (Which I did not see at the first time.)

• You can rewrite this C++ to java or
• you have to implement your antlr4::ANTLRErrorListener which does have methods reportAmbiguity, reportAttemptingFullContext etc. which are reporting when some performance problem appear. And then go through records manually.

[searocsun]

@Nic30 thank you so much.

[bernd5]

I tried the PL/SQL grammer with a CSharp target - it is slow here, too. And it reported some ambiguities...

Could you improve the grammar?

[nIxedoahz]

Can you tell me how to solve this problem？ Thanks

[kaby76]

Please take this conversation to here. This is a problem with the grammar, not Antlr. This issue should be closed here.