public bool CanAssign(Value left, Value right)
{
// Check if the left value is a variable
if (!(left is Variable)) {
var msg = "Cannot assign a value to a non-variable type";
throw new InvalidOperationException(msg);
}
return true;
}
public Value And(Value left, Value right)
{
// Convert values into literals
left = left.AsLiteral();
right = right.AsLiteral();
if (IsTrue(left)) {
return new Literal((Literal)right);
}
else {
return new Literal((Literal)left);
}
}
public Value Add(Value left, Value right)
{
// Convert values into literals
left = left.AsLiteral();
right = right.AsLiteral();
// Convert booleans into ints
if (ValueType.BOOL == left.Type) {
left = new Literal((bool)left.AsValue() ? 1 : 0);
}
if (ValueType.BOOL == right.Type) {
right = new Literal((bool)right.AsValue() ? 1 : 0);
}
var lVal = left.AsValue();
var rVal = right.AsValue();
// String concatenations
if (ValueType.STRING == left.Type && ValueType.STRING == right.Type) {
var lStr = lVal.ToString();
var rStr = rVal.ToString();
return new Literal(lStr + rStr);
}
if (ValueType.STRING == left.Type || ValueType.STRING == right.Type) {
string msg = "Cannot implicity convert to string";
throw new InvalidOperationException(msg);
}
// Arithmetic operations
if (ValueType.INT == left.Type) {
if (ValueType.INT == right.Type) {
return new Literal((int)lVal + (int)rVal);
}
if (ValueType.FLOAT == right.Type) {
return new Literal((int)lVal + (float)rVal);
}
}
if (ValueType.FLOAT == left.Type) {
if (ValueType.INT == right.Type) {
return new Literal((float)lVal + (int)rVal);
}
if (ValueType.FLOAT == right.Type) {
return new Literal((float)lVal + (float)rVal);
}
}
// The calculator doesn't know how to handle this type
throw new InvalidOperationException("Invalid value type");
}
/// <summary>
/// Assigns the right-hand Value to the left-hand Value.
/// </summary>
/// <param name="left">
/// The left-hand value.
/// </param>
/// <param name="right">
/// The right-hand value
/// </param>
public void Assign(Value left, Value right)
{
if (m_calculator.CanAssign(left, right)) {
var name = (left as Variable).Name;
if (m_variables.ContainsKey(name)) {
m_variables[name] = new Literal(right.AsLiteral());
}
else {
string msg = "Variable has not been instantiated";
throw new InvalidOperationException(msg);
}
}
else {
string msg = "Cannot assign value to variable";
throw new InvalidOperationException(msg);
}
}
public Value Xor(Value left, Value right)
{
// Convert values into literals
left = left.AsLiteral();
right = right.AsLiteral();
if (ValueType.FLOAT == left.Type || ValueType.FLOAT == right.Type) {
throw new InvalidOperationException("Invalid value type");
}
if (ValueType.STRING == left.Type || ValueType.STRING == right.Type) {
throw new InvalidOperationException("Invalid value type");
}
if (ValueType.BOOL == left.Type && ValueType.BOOL == right.Type) {
return new Literal(IsTrue(left) ^ IsTrue(right));
}
// Convert booleans into ints
if (ValueType.BOOL == left.Type) {
left = new Literal((bool)left.AsValue() ? 1 : 0);
}
if (ValueType.BOOL == right.Type) {
right = new Literal((bool)right.AsValue() ? 1 : 0);
}
// Perform bitwise xor on integers
if (ValueType.INT == left.Type && ValueType.INT == right.Type) {
return new Literal((int)left.AsValue() ^ (int)right.AsValue());
}
// The calculator doesn't know how to handle this type
throw new InvalidOperationException("Invalid value type");
}
public Value Not(Value value)
{
value = value.AsLiteral();
if (ValueType.BOOL == value.Type) {
value = new Literal((bool)value.AsValue() ? 1 : 0);
}
var obj = value.AsValue();
if (ValueType.INT == value.Type) {
return new Literal(0 == (int)obj);
}
if (ValueType.FLOAT == value.Type) {
return new Literal(0.0f == (float)obj);
}
if (ValueType.STRING == value.Type) {
return new Literal(0 == ((string)obj).Length);
}
// The calculator doesn't know how to handle this type
throw new InvalidOperationException("Invalid value type");
}
public Value LessThan(Value left, Value right)
{
// Convert values into literals
left = left.AsLiteral();
right = right.AsLiteral();
// Convert booleans into ints
if (ValueType.BOOL == left.Type) {
left = new Literal((bool)left.AsValue() ? 1 : 0);
}
if (ValueType.BOOL == right.Type) {
right = new Literal((bool)right.AsValue() ? 1 : 0);
}
var lVal = left.AsValue();
var rVal = right.AsValue();
// String comparison
if (ValueType.STRING == left.Type && ValueType.STRING == right.Type) {
string lStr = (string)lVal;
string rStr = (string)rVal;
int max = lStr.Length < rStr.Length ? rStr.Length : lStr.Length;
for (int i = 0; i < max; ++i) {
if (i >= lStr.Length && lStr.Length != rStr.Length) {
return new Literal(true);
}
if (i >= rStr.Length && lStr.Length != rStr.Length) {
return new Literal(false);
}
if (lStr[i] < rStr[i]) {
return new Literal(true);
}
else if (lStr[i] > rStr[i]) {
return new Literal(false);
}
}
// Strings are equal
return new Literal(false);
}
// Arithmetic operations
if (ValueType.INT == left.Type) {
if (ValueType.INT == right.Type) {
return new Literal((int)lVal < (int)rVal);
}
if (ValueType.FLOAT == right.Type) {
return new Literal((int)lVal < (float)rVal);
}
}
if (ValueType.FLOAT == left.Type) {
if (ValueType.INT == right.Type) {
return new Literal((float)lVal < (int)rVal);
}
if (ValueType.FLOAT == right.Type) {
return new Literal((float)lVal < (float)rVal);
}
}
// The calculator doesn't know how to handle this type
throw new InvalidOperationException("Invalid value type");
}
public Value GreaterThan(Value left, Value right)
{
return m_calculator.GreaterThan(left, right);
}
public Value Multiply(Value left, Value right)
{
return m_calculator.Multiply(left, right);
}
public bool CanAssign(Value left, Value right)
{
return m_calculator.CanAssign(left, right);
}
public Value And(Value left, Value right)
{
return m_calculator.And(left, right);
}
public Value Xor(Value left, Value right)
{
return m_calculator.Xor(left, right);
}
public Value Subtract(Value left, Value right)
{
return m_calculator.Subtract(left, right);
}
public Value Not(Value value)
{
return m_calculator.Not(value);
}
private bool IsTrue(Value value)
{
switch (value.Type) {
case ValueType.BOOL:
if (false == (bool)value.AsValue()) {
return false;
}
break;
case ValueType.INT:
if (0 == (int)value.AsValue()) {
return false;
}
break;
case ValueType.FLOAT:
if (0.0f == (float)value.AsValue()) {
return false;
}
break;
case ValueType.STRING:
if ("" == (string)value.AsValue()) {
return false;
}
break;
default:
throw new InvalidOperationException("Invalid value type");
}
return true;
}
public Value Divide(Value left, Value right)
{
return m_calculator.Divide(left, right);
}
public Value EqualTo(Value left, Value right)
{
return m_calculator.EqualTo(left, right);
}
public Value Divide(Value left, Value right)
{
// Convert values into literals
left = left.AsLiteral();
right = right.AsLiteral();
// Convert booleans into ints
if (ValueType.BOOL == left.Type) {
left = new Literal((bool)left.AsValue() ? 1 : 0);
}
if (ValueType.BOOL == right.Type) {
right = new Literal((bool)right.AsValue() ? 1 : 0);
}
var lVal = left.AsValue();
var rVal = right.AsValue();
// Arithmetic operations
if (ValueType.INT == right.Type) {
if (0 == (int)rVal) {
throw new DivideByZeroException();
}
}
if (ValueType.FLOAT == right.Type) {
if (0.0f == (float)rVal) {
throw new DivideByZeroException();
}
}
if (ValueType.INT == left.Type) {
if (ValueType.INT == right.Type) {
return new Literal((int)lVal / (int)rVal);
}
if (ValueType.FLOAT == right.Type) {
return new Literal((int)lVal / (float)rVal);
}
}
if (ValueType.FLOAT == left.Type) {
if (ValueType.INT == right.Type) {
return new Literal((float)lVal / (int)rVal);
}
if (ValueType.FLOAT == right.Type) {
return new Literal((float)lVal / (float)rVal);
}
}
// The calculator doesn't know how to handle this type
throw new InvalidOperationException("Invalid value type");
}
public Value LessThan(Value left, Value right)
{
return m_calculator.LessThan(left, right);
}