private ExpressionSyntax VisitExpression(ExpressionSyntax node)
{
if (node is BinaryExpressionSyntax binaryExpresson)
{
var left = Simplify(binaryExpresson.Left);
var right = Simplify(binaryExpresson.Right);
return(SF.BinaryExpression(node.Kind(), left, right));
}
if (node is IdentifierNameSyntax identifierName)
{
var value = Variables[identifierName.Identifier.Text];
return(value);
}
if (node is LiteralExpressionSyntax)
{
return(node);
}
// Consider:
// https://stackoverflow.com/a/3346729/2869093
// https://stackoverflow.com/a/7812241/2869093
if (node is PrefixUnaryExpressionSyntax prefixUnaryExpression)
{
if (prefixUnaryExpression.Operand is IdentifierNameSyntax operantIdentifierName)
{
operantIdentifierName = (IdentifierNameSyntax)prefixUnaryExpression.Operand;
var value = Variables[operantIdentifierName.Identifier.Text];
switch (node.Kind())
{
case SK.PreDecrementExpression:
return(SF.BinaryExpression(SK.SubtractExpression, value, SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(1))));
case SK.PreIncrementExpression:
return(SF.BinaryExpression(SK.AddExpression, value, SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(1))));
case SK.UnaryMinusExpression:
case SK.UnaryPlusExpression:
return(node);
default:
throw new NotImplementedException($"Unsupported expression type: {prefixUnaryExpression.Operand.GetType().Name} ({operantIdentifierName.Kind().ToString()})");
}
}
if (prefixUnaryExpression.Operand is LiteralExpressionSyntax)
{
return(node);
}
if (prefixUnaryExpression.Operand is ParenthesizedExpressionSyntax operandParenthesizedExpression)
{
return(SF.PrefixUnaryExpression(prefixUnaryExpression.Kind(), Simplify(operandParenthesizedExpression)));
}
throw new NotImplementedException($"Unsupported expression type: {prefixUnaryExpression.Operand.GetType().Name}");
}
if (node is PostfixUnaryExpressionSyntax postfixUnaryExpression)
{
if (postfixUnaryExpression.Operand is IdentifierNameSyntax operandIdentifierName)
{
var value = Variables[operandIdentifierName.Identifier.Text];
switch (node.Kind())
{
case SK.PostDecrementExpression:
return(SF.BinaryExpression(SK.SubtractExpression, value, SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(1))));
case SK.PostIncrementExpression:
return(SF.BinaryExpression(SK.AddExpression, value, SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(1))));
default:
throw new NotImplementedException($"Unsupported expression type: {postfixUnaryExpression.Operand.GetType().Name} ({operandIdentifierName.Kind().ToString()})");
}
}
if (postfixUnaryExpression.Operand is LiteralExpressionSyntax)
{
return(node);
}
if (postfixUnaryExpression.Operand is ParenthesizedExpressionSyntax operandParenthesizedExpression)
{
return(SF.PostfixUnaryExpression(postfixUnaryExpression.Kind(), Simplify(operandParenthesizedExpression)));
}
throw new NotImplementedException($"Unsupported expression type: {postfixUnaryExpression.Operand.GetType().Name}");
}
if (node is ParenthesizedExpressionSyntax parenthesizedExpression)
{
return(SF.ParenthesizedExpression(Simplify(parenthesizedExpression.Expression)));
}
throw new NotImplementedException($"Unsupported expression type: {node.GetType().Name}");
}