private object ReadOneInstruction()
{
if (UL == TypeSymbol.U_Var || UL == TypeSymbol.U_UnKown)
{
return(HandleAssign());
}
else if (UL == TypeSymbol.U_If)
{
return(HandleIf());
}
else if (UL == TypeSymbol.U_While)
{
return(HandleWhile());
}
else if (UL == TypeSymbol.U_For)
{
return(HandleFor());
}
else if (UL == TypeSymbol.U_Repeat)
{
return(HandleRepeatUntil());
}
else if (UL == TypeSymbol.U_Do)
{
return(HandleDoWhile());
}
else if (UL == TypeSymbol.U_Call)
{
return(HandleCall());
}
else if (UL == TypeSymbol.U_Write || UL == TypeSymbol.U_WriteLn)
{
return(HandleWrite());
}
else if (UL == TypeSymbol.U_Read)
{
return(HandleRead());
}
else if (UL == TypeSymbol.U_Return)
{
return(HandleReturn());
}
else if (UL == TypeSymbol.U_Break || UL == TypeSymbol.U_Halt || UL == TypeSymbol.U_Exit)
{
return(HandleBreadHaltExit());
}
else
{
GetSyntaxError(SyntaxMessagesError.InvalidToken, UL.ToString());
}
return(null);
}
private TExpression ReadFact(ref TExpression last)
{
if (UL == TypeSymbol.U_Cst_Int || UL == TypeSymbol.U_Cst_Real || UL == TypeSymbol.U_Cst_Str ||
UL == TypeSymbol.U_True || UL == TypeSymbol.U_False)
{
TExpression expNew = new TExpression();
expNew.UL = UL;
if (UL == TypeSymbol.U_Cst_Str)
{
expNew.ValStr = G_curr_Str;
}
else if (UL == TypeSymbol.U_Cst_Int || UL == TypeSymbol.U_Cst_Real) // the if statment i added after notce the true false.
{
expNew.ValNB = G_curr_Num;
}
// by default
expNew.Next = null;
expNew.Prev = null;
last = expNew;
UL = LexicalUnit();
return(expNew);
}
else if (UL == TypeSymbol.U_OpenParanthese)
{
UL = LexicalUnit();
TExpression expNew = ReadCondition(ref last);
if (UL != TypeSymbol.U_ClosedParanthese)
{
GetSyntaxError(WordMessagesError.NotFound, ")");
}
UL = LexicalUnit();
return(expNew);
}
else if (UL == TypeSymbol.U_Var || UL == TypeSymbol.U_VarDefine ||
UL == TypeSymbol.U_VarProcedure || UL == TypeSymbol.U_UnKown)
{
TExpression expNew = new TExpression();
// By Default
expNew.Next = null;
expNew.Prev = null;
TVar varAux = null;
ProcedureInstruction procAux = null;
TypeSymbol ulAux;
if (UL == TypeSymbol.U_VarDefine) // if the variable define
{
DefineInstruction defAux = (DefineInstruction)G_curr_ID;
expNew.UL = defAux.UL;
expNew.ValNB = defAux.ValNB;
expNew.ValStr = defAux.ValStr;
ulAux = defAux.UL;
UL = LexicalUnit();
}
else if (UL == TypeSymbol.U_UnKown) // if the variblae unknown procedure , unknown variable
{
string buffer = G_curr_Str;
UL = LexicalUnit();
if (UL == TypeSymbol.U_OpenParanthese) // if the variblae unknown procedure
{
IdentifierInstruction.AddIdentifier(buffer, ref Locals.gproc);
procAux = gProc;
gProc.IsFunc = true;
//gProc.IsDefined = false;
//gProc.PIN = null;
//gProc.POut = null;
//gproc.LVar = null;
//gProc.Linst = null;
ulAux = TypeSymbol.U_VarProcedure;
}
else // if the variblae unknown procedure , unknownvariable
{
IdentifierInstruction.AddIdentifier(buffer, ref Locals.gvar);
varAux = gVar;
ulAux = TypeSymbol.U_Var;
}
}
else // if the variable known
{
// this statment i am not sure about it
ulAux = UL;
if (ulAux == TypeSymbol.U_Var) // if the vairable known var
{
varAux = (TVar)G_curr_ID;
}
else // if the variable known procedure
{
procAux = (ProcedureInstruction)G_curr_ID;
}
UL = LexicalUnit();
}
expNew.UL = ulAux;
last = expNew;
if (ulAux == TypeSymbol.U_VarProcedure)
{
expNew.ValCall = ReadCall(procAux);
}
else if (ulAux == TypeSymbol.U_Var)
{
expNew.ValVar = varAux;
if (UL == TypeSymbol.U_OpenBracket)
{
UL = LexicalUnit();
expNew.Index = ReadExpression();
if (UL != TypeSymbol.U_ClosedBracket)
{
GetSyntaxError(WordMessagesError.NotFound, "]");
}
UL = LexicalUnit();
}
else
{
expNew.Index = null;
}
}
return(expNew);
}
else if (new TypeSymbol[] { TypeSymbol.U_Sin, TypeSymbol.U_Cos, TypeSymbol.U_Tg,
TypeSymbol.U_Ln, TypeSymbol.U_Log, TypeSymbol.U_Exp, TypeSymbol.U_Sqr, TypeSymbol.U_Sqrt,
TypeSymbol.U_Length, TypeSymbol.U_IntToStr, TypeSymbol.U_StrToInt, TypeSymbol.U_IntToHex, }.Contains(UL))
{
TExpression expNew = new TExpression();
expNew.UL = UL;
UL = LexicalUnit();
if (UL != TypeSymbol.U_OpenParanthese)
{
GetSyntaxError(WordMessagesError.NotFound, "(");
}
UL = LexicalUnit();
TExpression exp0 = ReadExpression(ref last);
last.Next = expNew;
expNew.Prev = last;
last = expNew;
if (UL != TypeSymbol.U_ClosedParanthese)
{
GetSyntaxError(WordMessagesError.NotFound, ")");
}
UL = LexicalUnit();
return(exp0);
}
else if (UL == TypeSymbol.U_Pluse || UL == TypeSymbol.U_Minus || UL == TypeSymbol.U_Not || UL == TypeSymbol.U_Complement)
{
TExpression expNew = new TExpression();
if (UL == TypeSymbol.U_Pluse)
{
expNew.UL = TypeSymbol.U_UnaryPluse;
}
else if (UL == TypeSymbol.U_Minus)
{
expNew.UL = TypeSymbol.U_UnaryMinuse;
}
else if (UL == TypeSymbol.U_Not)
{
expNew.UL = TypeSymbol.U_Not;
}
else
{
expNew.UL = TypeSymbol.U_Complement;
}
UL = LexicalUnit();
TExpression exp0 = ReadFact(ref last);
last.Next = expNew;
expNew.Prev = last;
last = expNew; // this statment i added to solve the problem that unary pluse and unary minus.
return(exp0);
}
else
{
GetSyntaxError(SyntaxMessagesError.InvalidToken, UL.ToString());
}
// this statment will never execute
// just for elminate compile time error.
return(null);
}