public static bool Equals(Expression left, Expression right)
{
if (!left.GetType().Equals(right.GetType()))
{
return(false);
}
if (left is BinaryExpression)
{
BinaryExpression bleft = (BinaryExpression)left;
BinaryExpression bright = (BinaryExpression)right;
return(bleft.Operator == bright.Operator && Equals(bleft.Left, bright.Left) && Equals(bleft.Right, bright.Right));
}
else if (left is LinearExpression)
{
LinearExpression lleft = (LinearExpression)left;
LinearExpression lright = (LinearExpression)right;
bool eq = lleft.Operator == lright.Operator && lleft.List.Count == lright.List.Count;
if (eq == false)
{
return(false);
}
for (int i = 0; i < lleft.List.Count; i++)
{
eq = eq && Equals(lleft[i], lright[i]);
}
return(eq);
}
else if (left is NumberExpression)
{
return(equalsNumber((NumberExpression)left, (NumberExpression)right));
}
else if (left is VariableExpression)
{
return(equalsVariable((VariableExpression)left, (VariableExpression)right));
}
else if (left is FunctionExpression)
{
return(equalsFunction((FunctionExpression)left, (FunctionExpression)right));
}
return(false);
}
public static bool Contains(Expression expr, Expression sub)
{
if (expr.GetType().Equals(sub.GetType()))
{
return(expr.Equals(sub));
}
if (expr is BinaryExpression)
{
BinaryExpression bexpr = (BinaryExpression)expr;
return(Contains(bexpr.Left, sub) && Contains(bexpr.Right, sub));
}
else if (expr is LinearExpression)
{
LinearExpression lexpr = (LinearExpression)expr;
bool contains = true;
foreach (Expression item in lexpr.List)
{
contains = contains && Contains(item, sub);
}
return(contains);
}
else if (expr is FunctionExpression)
{
FunctionExpression fexpr = (FunctionExpression)expr;
bool contains = true;
foreach (Expression arg in fexpr.Arguments)
{
contains = contains && Contains(arg, sub);
}
return(contains);
}
return(false);
}
private bool match(Expression expr, Expression pattern)
{
if (!(pattern is VariableExpression))
{
if (!expr.GetType().Equals(pattern.GetType()))
return false;
if (pattern is BinaryExpression)
{
BinaryExpression bexpr = (BinaryExpression)expr;
BinaryExpression bpattern = (BinaryExpression)pattern;
if (bexpr.Operator != bpattern.Operator)
return false;
return match(bexpr.Left, bpattern.Left) && match(bexpr.Right, bpattern.Right);
}
else if (pattern is FunctionExpression)
{
FunctionExpression fexpr = (FunctionExpression)expr;
FunctionExpression fpattern = (FunctionExpression)pattern;
if (fexpr.Name != fpattern.Name || fexpr.Arguments.Count != fpattern.Arguments.Count)
return false;
bool matching = true;
for (int i = 0; i < fexpr.Arguments.Count; i++)
matching = matching && match(fexpr.Arguments[i], fpattern.Arguments[i]);
return matching;
}
return expr.Equals(pattern);
}
else
{
VariableExpression vpattern = (VariableExpression)pattern;
string name = vpattern.Name;
if (matches.ContainsKey(name))
{
Expression fmatch = matches[name];
if (!expr.Equals(fmatch))
return false;
}
matches[name] = expr;
return true;
}
}
private bool match(Expression expr, Expression pattern)
{
if (!(pattern is VariableExpression))
{
if (!expr.GetType().Equals(pattern.GetType()))
{
return(false);
}
if (pattern is BinaryExpression)
{
BinaryExpression bexpr = (BinaryExpression)expr;
BinaryExpression bpattern = (BinaryExpression)pattern;
if (bexpr.Operator != bpattern.Operator)
{
return(false);
}
return(match(bexpr.Left, bpattern.Left) && match(bexpr.Right, bpattern.Right));
}
else if (pattern is FunctionExpression)
{
FunctionExpression fexpr = (FunctionExpression)expr;
FunctionExpression fpattern = (FunctionExpression)pattern;
if (fexpr.Name != fpattern.Name || fexpr.Arguments.Count != fpattern.Arguments.Count)
{
return(false);
}
bool matching = true;
for (int i = 0; i < fexpr.Arguments.Count; i++)
{
matching = matching && match(fexpr.Arguments[i], fpattern.Arguments[i]);
}
return(matching);
}
return(expr.Equals(pattern));
}
else
{
VariableExpression vpattern = (VariableExpression)pattern;
string name = vpattern.Name;
if (matches.ContainsKey(name))
{
Expression fmatch = matches[name];
if (!expr.Equals(fmatch))
{
return(false);
}
}
matches[name] = expr;
return(true);
}
}
