public static Expression Member(Expression lhs, string memberName)
{
if (!lhs.Type.IsDynamic())
{
return(Expression.PropertyOrField(lhs, memberName));
}
return(DynamicOp.GetMember(lhs, memberName));
}
public static Expression Negate(Expression lhs)
{
if (lhs.Type.IsDynamic())
{
return(DynamicOp.UnaryOp(lhs, ExpressionType.Negate));
}
return(Expression.Negate(lhs));
}
/// <summary>produce comparison based on IComparable types</summary>
public static Expression CompareTo(Expression lhs, Expression rhs, ExpressionType exprType)
{
if (lhs.Type.IsDynamic() || rhs.Type.IsDynamic())
{
return(DynamicOp.BinaryOpPredicate(lhs, rhs, exprType));
}
lhs = ExpressionHelper.Coerce(lhs, rhs);
rhs = ExpressionHelper.Coerce(rhs, lhs);
var compareToMethod = lhs.Type.GetMethod("CompareTo", new[] { rhs.Type })
?? lhs.Type.GetMethod("CompareTo", new[] { typeof(object) });
if (compareToMethod == null)
{
throw new ArgumentException("unexpected IComparable types for instance: " + lhs.Type + " compared to " + rhs.Type);
}
Expression compare = Expression.Call(lhs, compareToMethod, new[] { rhs });
return(CompareTo(exprType, compare));
}
public static Expression MathOp(Expression lhs, Expression rhs, ExpressionType expressionType)
{
var coerceLeft = ExpressionHelper.Coerce(lhs, rhs);
var coerceRight = ExpressionHelper.Coerce(rhs, lhs);
if (lhs.Type.IsDynamic() || rhs.Type.IsDynamic())
{
DynamicOp.BinaryOp(coerceLeft, coerceRight, expressionType);
}
Expression expression;
switch (expressionType)
{
case ExpressionType.Add:
expression = Expression.Add(coerceLeft, coerceRight);
break;
case ExpressionType.Subtract:
expression = Expression.Subtract(coerceLeft, coerceRight);
break;
case ExpressionType.Multiply:
expression = Expression.Multiply(coerceLeft, coerceRight);
break;
case ExpressionType.Divide:
expression = Expression.Divide(coerceLeft, coerceRight);
break;
case ExpressionType.Modulo:
expression = Expression.Modulo(coerceLeft, coerceRight);
break;
default:
throw new ArgumentException("unknown math type: " + expressionType);
}
return(expression);
}
