sptr<ExprNode> Parser::ParseMul()
{
sptr<ExprNode> mul = ParseUnary();
while (Match(MUL, DIVIS, DIV, MOD, AND, -1))
{
mul = sptr<MulNode>(new MulNode(currToken, mul));
NextToken();
dynamic_pointer_cast<MulNode>(mul)->PushChild(ParseUnary());
}
return mul;
}
// binoprhs
// ::= ('+' unary)*
std::unique_ptr<CExprAST> CParser::ParseBinOpRHS(int precedence, std::unique_ptr<CExprAST> lhs)
{
// If this is a binary operation, find its precedence
while (true) {
int p = GetTokenPrecedence();
// If this is a binop that binds at least as tightly as the current binop,
// consume it, otherwise we are done
if (p < precedence)
return lhs;
int binop = m_CurrentToken;
GetNextToken(); // eating that binop
// Parsing unary expression after the binary operator
auto rhs = ParseUnary();
if (!rhs)
return nullptr;
// If binop binds less tightly that the operator after rhs,
// let the pending operator take rhs as it lhs
int nextp = GetTokenPrecedence();
if (p < nextp) {
rhs = ParseBinOpRHS(p + 1, std::move(rhs));
if (!rhs)
return nullptr;
}
// Merge lhs/rhs
lhs = std::make_unique<CBinaryExprAST>(binop, std::move(lhs), std::move(rhs));
}
}
// expression
// ::= unary binoprhs
//
std::unique_ptr<CExprAST> CParser::ParseExpression()
{
auto lhs = ParseUnary();
if (!lhs)
return nullptr;
return ParseBinOpRHS(0, std::move(lhs));
}
sptr<ExprNode> Parser::ParseUnary()
{
if (Match(PLUS, MINUS, NOT, -1))
{
sptr<Token> buff = currToken;
NextToken();
return sptr<UnOpNode>(new UnOpNode(buff, ParseUnary()));
}
else
{
return ParsePrimary();
}
}
// unary
// ::= primary
// ::= '!' unary
std::unique_ptr<CExprAST> CParser::ParseUnary()
{
// If current token is not an operator, it must be a primary expr
if (!isascii(m_CurrentToken) || m_CurrentToken == '(' || m_CurrentToken == ',')
return ParsePrimary();
// If this is an unary operator, read it
int opcode = m_CurrentToken;
GetNextToken();
auto operand = ParseUnary();
if (operand)
return std::make_unique<CUnaryExprAST>(opcode, std::move(operand));
return nullptr;
}
void ParseExprA()
{
loop:
ParseUnary();
if(Token==TOK_ADD || Token==TOK_SUB || Token==TOK_MUL || Token==TOK_DIV || Token==TOK_MOD ||
Token==TOK_GE || Token==TOK_GT || Token==TOK_LE || Token==TOK_LT || Token==TOK_EQ || Token==TOK_NE ||
Token==TOK_AND || Token==TOK_OR || Token==TOK_EOR || Token==TOK_ANDAND || Token==TOK_OROR || Token==TOK_LEFT || Token==TOK_RIGHT ||
Token==TOK_ASSADD || Token==TOK_ASSSUB || Token==TOK_ASSMUL || Token==TOK_ASSDIV || Token==TOK_ASSMOD ||
Token==TOK_ASSAND || Token==TOK_ASSOR || Token==TOK_ASSEOR || Token==TOK_ASSLEFT || Token==TOK_ASSRIGHT ||
Token==TOK_PTR || Token==TOK_ASSIGN/* || Token==TOK_COMMA*/)
{
Match();
goto loop;
}
}
