public InitialValue EvaluateConstExpression(TokenExpression expression, bool constOnly)
{
if (expression == null)
{
return(null);
}
//leaf? )
if (expression.Subexpressions.Count == 0)
{
if (expression.TokenType == TokenType.Identifier)
{
IVariable variable = Symbols.GetOrNull(expression.Token.Value);
if (variable == null)
{
return(null);
}
if (constOnly)
{
if (Parent.Constants.Contains(expression.Token.Value))
{
}
else
{
return(null);
}
}
if (InitialValues.ContainsKey(variable))
{
return(InitialValues[variable]);
}
else
{
if (variable.DataType.IsInteger())
{
return(new InitialValue(0));
}
else if (variable.DataType.IsFloat())
{
return(new InitialValue(0.0f));
}
else if (variable.DataType.IsString())
{
return(new InitialValue(""));
}
else if (variable.DataType == DataType.Bool || variable.DataType == DataType.RefBool)
{
return(new InitialValue(false));
}
else if (variable is Function)
{
return(new InitialValue(variable.Index));
}
}
return(null);
}
else if (expression.TokenType == TokenType.Number)
{
if (expression.Token.IsInt())
{
return(new InitialValue(expression.Token.ToInt()));
}
else if (expression.Token.IsFloat())
{
return(new InitialValue(expression.Token.ToFloat()));
}
}
else if (expression.TokenType == TokenType.StringLiteral)
{
return(new InitialValue(expression.Token.Value));
}
else if (expression.TokenType == TokenType.CharLiteral)
{
var bytes = Extensions.BinaryEncoding.GetBytes(expression.Token.Value);
if (bytes.Length > 1)
{
return(new InitialValue(bytes[1] * 256 + bytes[0]));
}
else
{
return(new InitialValue(bytes[0]));
}
}
return(null);
}
//unary operator?
if (expression.Subexpressions.Count == 1)
{
var a = EvaluateConstExpression(expression.Subexpressions[0], constOnly);
if (a == null)
{
return(null);
}
switch (expression.TokenType)
{
case TokenType.Complement:
{
if (a.DataType == DataType.Int || a.DataType == DataType.Bool)
{
return(new InitialValue(~a.IntValue));
}
return(null);
}
case TokenType.Not:
{
if (a.DataType == DataType.Int || a.DataType == DataType.Bool)
{
return(new InitialValue(a.IntValue != 0));
}
if (a.DataType == DataType.Float)
{
return(new InitialValue(a.FloatValue != 0));
}
return(null);
}
case TokenType.Negative:
{
if (a.DataType == DataType.Int || a.DataType == DataType.Bool)
{
return(new InitialValue(-a.IntValue));
}
else if (a.DataType == DataType.Float)
{
return(new InitialValue(-a.FloatValue));
}
return(null);
}
case TokenType.Positive:
case TokenType.PostDecrement:
case TokenType.PostIncrement:
{
if (a.DataType == DataType.Int || a.DataType == DataType.Bool || a.DataType == DataType.Float)
{
return(a);
}
return(null);
}
case TokenType.PreIncrement:
{
if (a.DataType == DataType.Int || a.DataType == DataType.Bool)
{
return(new InitialValue(a.IntValue + 1));
}
else if (a.DataType == DataType.Float)
{
return(new InitialValue(a.FloatValue + 1.0f));
}
return(null);
}
case TokenType.PreDecrement:
{
if (a.DataType == DataType.Int || a.DataType == DataType.Bool)
{
return(new InitialValue(a.IntValue - 1));
}
else if (a.DataType == DataType.Float)
{
return(new InitialValue(a.FloatValue - 1.0f));
}
return(null);
}
case TokenType.AddressOf:
{
if (a.DataType == DataType.Int)
{
if (expression.Subexpressions[0].TokenType == TokenType.Identifier && Symbols[expression.Subexpressions[0].Token.Value] is Function)
{
return(a);
}
}
return(null);
}
}
return(null);
}
//binary expression?
if (expression.Subexpressions.Count == 2)
{
var a = EvaluateConstExpression(expression.Subexpressions[0], constOnly);
var b = EvaluateConstExpression(expression.Subexpressions[1], constOnly);
//cast expressions (expressed as a functioncall)
if (expression.TokenType == TokenType.FunctionCall && b != null)
{
var exprA = expression.Subexpressions[0];
if (exprA.TokenType == TokenType.String)
{
if (b.DataType == DataType.String)
{
return(b);
}
else
{
return(new InitialValue(b.GetValue()));
}
}
else if (exprA.TokenType == TokenType.Float)
{
InitialValue v = new InitialValue();
if (v.SetValue(DataType.Float, b.GetValue()))
{
return(v);
}
else
{
return(null);
}
}
else if (exprA.TokenType == TokenType.Int)
{
InitialValue v = new InitialValue();
if (v.SetValue(DataType.Int, b.GetValue()))
{
return(v);
}
else
{
return(null);
}
}
}
if (expression.TokenType == TokenType.Assign)
{
return(b);
}
if (a == null || b == null)
{
return(null);
}
if (a.DataType == DataType.Float || b.DataType == DataType.Float)
{
float floatA;
float floatB;
if (a.DataType == DataType.Int || a.DataType == DataType.Bool)
{
floatA = a.IntValue;
}
else if (a.DataType == DataType.Float)
{
floatA = a.FloatValue;
}
else
{
return(null);
}
if (b.DataType == DataType.Int || b.DataType == DataType.Bool)
{
floatB = b.IntValue;
}
else if (b.DataType == DataType.Float)
{
floatB = b.FloatValue;
}
else
{
return(null);
}
switch (expression.TokenType)
{
case TokenType.Multiply:
case TokenType.MultiplyAssign:
return(new InitialValue(floatA * floatB));
case TokenType.Divide:
case TokenType.DivideAssign:
return(new InitialValue(floatA / floatB));
case TokenType.Modulo:
case TokenType.ModuloAssign:
return(new InitialValue(floatA % floatB));
case TokenType.Plus:
case TokenType.PlusAssign:
return(new InitialValue(floatA + floatB));
case TokenType.Minus:
case TokenType.MinusAssign:
return(new InitialValue(floatA - floatB));
case TokenType.LeftShift:
case TokenType.LeftShiftAssign:
return(new InitialValue((int)floatA << (int)floatB));
case TokenType.RightShift:
case TokenType.RightShiftAssign:
return(new InitialValue((int)floatA << (int)floatB));
case TokenType.LessThan:
return(new InitialValue(floatA < floatB));
case TokenType.LessThanOrEqualTo:
return(new InitialValue(floatA <= floatB));
case TokenType.GreaterThan:
return(new InitialValue(floatA > floatB));
case TokenType.GreaterThanOrEqualTo:
return(new InitialValue(floatA >= floatB));
case TokenType.EqualTo:
return(new InitialValue(floatA == floatB));
case TokenType.NotEqualTo:
return(new InitialValue(floatA != floatB));
case TokenType.And:
case TokenType.AndAssign:
return(new InitialValue((int)floatA & (int)floatB));
case TokenType.Xor:
case TokenType.XorAssign:
return(new InitialValue((int)floatA ^ (int)floatB));
case TokenType.Or:
case TokenType.OrAssign:
return(new InitialValue((int)floatA | (int)floatB));
case TokenType.LogicalAnd:
return(new InitialValue((floatA != 0) && (floatB != 0)));
case TokenType.LogicalOr:
return(new InitialValue((floatA != 0) || (floatB != 0)));
case TokenType.Assign:
return(new InitialValue(floatB));
}
return(null);
}
if (a.DataType == DataType.String && b.DataType == DataType.String)
{
string stringA = a.StringValue ?? "";
string stringB = b.StringValue ?? "";
switch (expression.TokenType)
{
case TokenType.Plus:
case TokenType.PlusAssign:
return(new InitialValue(stringA + stringB));
case TokenType.LessThan:
return(new InitialValue(String.Compare(stringA, stringB) < 0));
case TokenType.LessThanOrEqualTo:
return(new InitialValue(String.Compare(stringA, stringB) <= 0));
case TokenType.GreaterThan:
return(new InitialValue(String.Compare(stringA, stringB) > 0));
case TokenType.GreaterThanOrEqualTo:
return(new InitialValue(String.Compare(stringA, stringB) >= 0));
case TokenType.EqualTo:
return(new InitialValue(stringA == stringB));
case TokenType.NotEqualTo:
return(new InitialValue(stringA != stringB));
case TokenType.LogicalAnd:
return(new InitialValue((stringA != "") && (stringB != "")));
case TokenType.LogicalOr:
return(new InitialValue((stringA != "") || (stringB != "")));
case TokenType.Assign:
return(new InitialValue(stringB));
}
return(null);
}
{
int intA;
int intB;
if (a.DataType == DataType.Int || a.DataType == DataType.Bool)
{
intA = a.IntValue;
}
else
{
return(null);
}
if (b.DataType == DataType.Int || b.DataType == DataType.Bool)
{
intB = b.IntValue;
}
else
{
return(null);
}
switch (expression.TokenType)
{
case TokenType.Multiply:
case TokenType.MultiplyAssign:
return(new InitialValue(intA * intB));
case TokenType.Divide:
case TokenType.DivideAssign:
return(new InitialValue(intA / intB));
case TokenType.Modulo:
case TokenType.ModuloAssign:
return(new InitialValue(intA % intB));
case TokenType.Plus:
case TokenType.PlusAssign:
return(new InitialValue(intA + intB));
case TokenType.Minus:
case TokenType.MinusAssign:
return(new InitialValue(intA - intB));
case TokenType.LeftShift:
case TokenType.LeftShiftAssign:
return(new InitialValue(intA << intB));
case TokenType.RightShift:
case TokenType.RightShiftAssign:
return(new InitialValue(intA << intB));
case TokenType.LessThan:
return(new InitialValue(intA < intB));
case TokenType.LessThanOrEqualTo:
return(new InitialValue(intA <= intB));
case TokenType.GreaterThan:
return(new InitialValue(intA > intB));
case TokenType.GreaterThanOrEqualTo:
return(new InitialValue(intA >= intB));
case TokenType.EqualTo:
return(new InitialValue(intA == intB));
case TokenType.NotEqualTo:
return(new InitialValue(intA != intB));
case TokenType.And:
case TokenType.AndAssign:
return(new InitialValue(intA & intB));
case TokenType.Xor:
case TokenType.XorAssign:
return(new InitialValue(intA ^ intB));
case TokenType.Or:
case TokenType.OrAssign:
return(new InitialValue(intA | intB));
case TokenType.LogicalAnd:
return(new InitialValue((intA != 0) && (intB != 0)));
case TokenType.LogicalOr:
return(new InitialValue((intA != 0) || (intB != 0)));
case TokenType.Assign:
return(new InitialValue(intB));
}
return(null);
}
}
return(null);
}