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add error handling to the parser

This commit is contained in:
Chris Cromer 2022-11-22 11:34:07 -03:00
parent 4788eeaa37
commit 4ca7ff0ba6
Signed by: cromer
GPG Key ID: FA91071797BEEEC2
2 changed files with 43 additions and 44 deletions
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65
src/parser.cpp
View File

@ -5,6 +5,7 @@
#include <memory>
#include <stack>
#include <string>
#include <vector>
obelisk::Parser::Parser()
@ -213,50 +214,10 @@ std::unique_ptr<obelisk::PrototypeAST> obelisk::Parser::parseExtern()
std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseAction()
{
//action(is "dangerous" then "avoid" or "ignore");
getNextToken();
if (getCurrentToken() != '(')
{
// TODO: throw an error
}
}
std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseRule()
{
//rule("player" can "die" if "enemy1" is "dangerous");
getNextToken();
if (getCurrentToken() != '(')
{
// TODO: throw an error
}
while (true) //left side of Rule
{
getNextToken();
if (getCurrentToken() != '"')
{
//TODO: throw an error
}
/*if (getCurrentToken() == ')') // TODO: break if not string and not "and"
{
// TODO: save the verb
break;
}*/
}
while (true) //right side of Rule
{
getNextToken();
if (getCurrentToken() != '"')
{
//TODO: throw an error
}
if (getCurrentToken() == ')')
{
// TODO: save the verb
break;
}
}
}
// fact("chris cromer" and "martin" and "Isabella" can "program" and "speak english");
@ -268,7 +229,8 @@ std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseFact()
getNextToken();
if (getCurrentToken() != '(')
{
// TODO: throw an error
throw obelisk::ParserException(
"expected '(' but got '" + std::to_string(getCurrentToken()) + "'");
}
syntax.push('(');
@ -326,14 +288,29 @@ std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseFact()
{
if (getCurrentToken() == ')')
{
// TODO: throw an error if verb is empty
// TODO: throw an error if rightEntities has 0 elements
// closing parenthesis found, make sure we have everything needed
if (verb == "")
{
throw obelisk::ParserException("verb is empty");
}
if (leftEntities.size() == 0)
{
throw obelisk::ParserException(
"missing left side entities");
}
if (rightEntities.size() == 0)
{
throw obelisk::ParserException(
"missing right side entities");
}
break;
}
if (getCurrentToken() == '"')
{
// TODO: throw and error because there is an unexpected double quote.
throw obelisk::ParserException("unexpected '\"'");
break;
}

22
src/parser.h
View File

@ -52,6 +52,28 @@ namespace obelisk
void handleRule();
void handleFact();
};
class ParserException : public std::exception
{
private:
const std::string errorMessage_;
public:
ParserException() :
errorMessage_("an unknown error ocurred")
{
}
ParserException(const std::string& errorMessage) :
errorMessage_(errorMessage)
{
}
const char* what() const noexcept
{
return errorMessage_.c_str();
}
};
} // namespace obelisk
#endif