This should fix multi-threaded parsing. Not a clean solution, I am guessing the following block should be a single, state-less pattern? @mrks
```
\' { BEGIN singlequotedstring; strbuf = std::stringstream{}; }
<singlequotedstring>\'\' { strbuf << '\''; }
<singlequotedstring>[^']* { strbuf << yytext; }
<singlequotedstring>\' { BEGIN 0; yylval->sval = strdup(strbuf.str().c_str()); return SQL_STRING; }
<singlequotedstring><<EOF>> { fprintf(stderr, "[SQL-Lexer-Error] Unterminated string\n"); return 0; }
```
Anyway, the following hyrise playground does not crash anymore, so Toni should be able to work with this for the time being.
```c++
#include <iostream>
#include <thread>
#include "types.hpp"
#include "tpch/tpch_queries.hpp"
#include "SQLParser.h"
using namespace opossum; // NOLINT
int main() {
std::vector<std::thread> threads;
for (size_t t = 0; t < 200; ++t) {
threads.emplace_back([&]() {
for (size_t p = 0; p < 10'000; ++p) {
hsql::SQLParserResult result;
hsql::SQLParser::parse(tpch_queries.at(19), &result);
std::cout << "Parsing " << p << " is valid: " << result.isValid() << std::endl;
}
});
}
for (auto& thread : threads) {
thread.join();
}
return 0;
}
```
* Got ISNULL working
* Allow function calls with no arguments
* Added no-else cases and arrays
* Added more operations including ilike, concat
* Added optional all to set operations and fixed natural join
* Ran astyle
* Used the appropriate star expression
Instead of using a ColumnRef with star literal.
* NULL expressions now returns true isLiteral
* Fixed structure for no-else case clauses
* Fixed up grammar conflicts
