DynamicMemberAssignment.cs

using System;
using System.Reflection;
using System.Threading.Tasks;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Operators.Membership;
using Waher.Script.Operators.Vectors;
 
namespace Waher.Script.Operators.Assignments
{
    public class DynamicMemberAssignment : TernaryOperator
    {
        public DynamicMemberAssignment(DynamicMember DynamicMember, ScriptNode Operand, int Start, int Length, Expression Expression)
            : base(DynamicMember.LeftOperand, DynamicMember.RightOperand, Operand, Start, Length, Expression)
        {
        }
 
        public override IElement Evaluate(Variables Variables)
        {
            IElement Left = this.left.Evaluate(Variables);
            IElement Middle = this.middle.Evaluate(Variables);
            IElement Right = this.right.Evaluate(Variables);
 
            if (Middle.IsScalar)
                return this.Evaluate(Left, Middle, Right);
            else
            {
                foreach (IElement MiddleElement in Middle.ChildElements)
                    this.Evaluate(Left, MiddleElement, Right);
 
                return Right;
            }
        }
 
        public override async Task<IElement> EvaluateAsync(Variables Variables)
        {
            if (!this.isAsync)
                return this.Evaluate(Variables);
 
            IElement Left = await this.left.EvaluateAsync(Variables);
            IElement Middle = await this.middle.EvaluateAsync(Variables);
            IElement Right = await this.right.EvaluateAsync(Variables);
 
            if (Middle.IsScalar)
                return this.Evaluate(Left, Middle, Right);
            else
            {
                foreach (IElement MiddleElement in Middle.ChildElements)
                    this.Evaluate(Left, MiddleElement, Right);
 
                return Right;
            }
        }
 
        public IElement Evaluate(IElement Left, IElement Middle, IElement Right)
        {
            if (!(Middle.AssociatedObjectValue is string Name))
                throw new ScriptRuntimeException("Member names must be strings.", this);
 
            object LeftValue = Left.AssociatedObjectValue;
            Type Type = LeftValue.GetType();
 
            PropertyInfo Property = Type.GetRuntimeProperty(Name);
            if (!(Property is null))
            {
                if (!Property.CanWrite)
                    throw new ScriptRuntimeException("Property cannot be set: " + Name, this);
                else if (!Property.SetMethod.IsPublic)
                    throw new ScriptRuntimeException("Property not accessible: " + Name, this);
                else
                {
                    Type = Property.PropertyType;
                    if (!Type.IsAssignableFrom(Right.GetType().GetTypeInfo()))
                        Property.SetValue(LeftValue, Expression.ConvertTo(Right, Type, this), null);
                    else
                        Property.SetValue(LeftValue, Right, null);
                }
            }
            else
            {
                FieldInfo Field = Type.GetRuntimeField(Name);
                if (!(Field is null))
                {
                    if (!Field.IsPublic)
                        throw new ScriptRuntimeException("Field not accessible: " + Name, this);
                    else
                    {
                        Type = Field.FieldType;
                        if (!Type.IsAssignableFrom(Right.GetType().GetTypeInfo()))
                            Field.SetValue(Left, Expression.ConvertTo(Right, Type, this));
                        else
                            Field.SetValue(Left, Right);
                    }
                }
                else
                {
                    if (VectorIndex.TryGetIndexProperty(Type, false, true, out Property, 
                        out ParameterInfo[] IndexArguments) &&
                        (IndexArguments?.Length ?? 0) == 1)
                    {
                        object[] Index;
 
                        if (IndexArguments[0].ParameterType == typeof(string))
                            Index = new object[] { Name };
                        else
                            Index = new object[] { Expression.ConvertTo(Name, IndexArguments[0].ParameterType, this) };
 
                        Type = Property.PropertyType;
                        if (Type == typeof(object))
                            Property.SetValue(LeftValue, Right.AssociatedObjectValue, Index);
                        else if (Type.IsAssignableFrom(Right.GetType().GetTypeInfo()))
                            Property.SetValue(LeftValue, Right, Index);
                        else
                            Property.SetValue(LeftValue, Expression.ConvertTo(Right, Type, this), Index);
                    }
                    else
                        throw new ScriptRuntimeException("Member '" + Name + "' not found on type '" + Type.FullName + "'.", this);
                }
            }
 
            return Right;
        }
 
    }
}