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;
}
}
