//式の解析
public static ExprAST CreateSikiAST(TokenStream tokenst)
{
tokenst.SetCheckPoint();
ExprAST exprAST = CreateKouAST(tokenst);
if (exprAST == null)
{
tokenst.Rollback();
return(null);
}
while (tokenst.NowIndex < tokenst.Size)
{
string opstr = tokenst.Get().Str;
if (opstr == "+" || opstr == "-")
{
tokenst.Next();
ExprAST baseAST2 = CreateKouAST(tokenst);
if (baseAST2 == null)
{
tokenst.Rollback();
return(null);
}
if (opstr == "+")
{
exprAST = new BinaryExprAST(BinaryExprAST.Op.Add, exprAST, baseAST2);
}
else
{
exprAST = new BinaryExprAST(BinaryExprAST.Op.Sub, exprAST, baseAST2);
}
}
else
{
break;
}
}
return(exprAST);
}
//項の解析
static ExprAST CreateKouAST(TokenStream tokenst)
{
ExprAST exprAST;
bool minusFlag = false;
//実数
if (tokenst.Get().Str == "-")
{
minusFlag = true;
tokenst.Next();
}
if (tokenst.Get().TokenType == TokenType.Double)
{
exprAST = new DoubleAST(tokenst.Get().GetDouble());
tokenst.Next();
}
//関数
else
{
exprAST = CreateFuncCallAST(tokenst);
if (exprAST == null)
{
//変数
if (tokenst.Get().TokenType == TokenType.Identifier && variableTable.Find(tokenst.Get().Str) != null)
{
exprAST = new DoubleAST(variableTable.Find(tokenst.Get().Str).Value);
tokenst.Next();
}
else
{
exprAST = CreateLambdaCallAST(tokenst);
if (exprAST == null)
{
//（式）
if (tokenst.Get().TokenType == TokenType.LeftKakko)
{
tokenst.Next();
exprAST = CreateSikiAST(tokenst);
if (exprAST == null)
{
return(null);
}
if (tokenst.Get().TokenType != TokenType.RightKakko)
{
return(null);
}
tokenst.Next();
}
else
{
return(null);
}
}
}
}
}
if (tokenst.NowIndex >= tokenst.Size)
{
return(minusFlag ?exprAST = new MinusAST(exprAST) : exprAST);
}
string opstr = tokenst.Get().Str;
if (opstr == "*" || opstr == "/")
{
ExprAST baseAST2;
tokenst.Next();
baseAST2 = CreateKouAST(tokenst);
if (baseAST2 == null)
{
return(null);
}
if (opstr == "*")
{
exprAST = new BinaryExprAST(BinaryExprAST.Op.Mul, exprAST, baseAST2);
}
else if (opstr == "/")
{
exprAST = new BinaryExprAST(BinaryExprAST.Op.Div, exprAST, baseAST2);
}
return(minusFlag ? exprAST = new MinusAST(exprAST) : exprAST);
}
return(minusFlag ? exprAST = new MinusAST(exprAST) : exprAST);
}
