public BinaryExprAST(char op, ExprAST lhs, ExprAST rhs)
{
this.Op = op;
this.LHS = lhs;
this.RHS = rhs;
}
/// binoprhs
/// ::= ('+' primary)*
private ExprAST ParseBinOpRHS(int exprPrec, ExprAST lhs)
{
// If this is a binop, find its precedence.
while(true)
{
int tokPrec = GetTokenPrecedence();
// If this is a binop that binds at least as tightly as the current binop,
// consume it, otherwise we are done.
if(tokPrec < exprPrec)
return lhs;
// Okay, we know this is a binop.
char binOp = m_token.IdentiferText[0];
GetNextToken();
// Parse the primary expression after the binary operator.
ExprAST rhs = ParsePrimary();
if(rhs == null)
return null;
// If BinOp binds less tightly with RHS than the operator after RHS, let
// the pending operator take RHS as its LHS.
int nextPrec = GetTokenPrecedence();
if(tokPrec < nextPrec)
{
rhs = ParseBinOpRHS(tokPrec + 1, rhs);
if(rhs == null)
return null;
}
// Merge LHS/RHS.
lhs = new BinaryExprAST(binOp, lhs, rhs);
}
}
public FunctionAST(PrototypeAST proto, ExprAST body)
{
this.Proto = proto;
this.Body = body;
}