BadPreDecrementExpression.cs

Go to the documentation of this file.

using BadScript2.Common;
using BadScript2.Runtime;
using BadScript2.Runtime.Error;
using BadScript2.Runtime.Objects;
using BadScript2.Runtime.Objects.Native;
 
namespace BadScript2.Parser.Expressions.Binary.Math.Atomic;
 
public class BadPreDecrementExpression : BadExpression
{
    public readonly BadExpression Right;
 
    public BadPreDecrementExpression(BadExpression right, BadSourcePosition position) : base(
        right.IsConstant,
        position
    )
    {
        Right = right;
    }
 
    public override IEnumerable<BadExpression> GetDescendants()
    {
        return Right.GetDescendantsAndSelf();
    }
 
    public static BadObject Decrement(BadObjectReference reference, BadSourcePosition position)
    {
        BadObject right = reference.Dereference();
 
        if (right is not IBadNumber leftNumber)
        {
            throw new BadRuntimeException("Right side of -- must be a number", position);
        }
 
        BadObject r = leftNumber.Value - 1;
        reference.Set(r);
 
        return r;
    }
 
    protected override IEnumerable<BadObject> InnerExecute(BadExecutionContext context)
    {
        BadObject right = BadObject.Null;
 
        foreach (BadObject o in Right.Execute(context))
        {
            right = o;
 
            yield return o;
        }
 
        if (right is not BadObjectReference rightRef)
        {
            throw new BadRuntimeException("Right side of -- must be a reference", Position);
        }
 
        foreach (BadObject o in DecrementWithOverride(context, rightRef, Position))
        {
            yield return o;
        }
    }
 
    public static IEnumerable<BadObject> DecrementWithOverride(
        BadExecutionContext? context,
        BadObjectReference leftRef,
        BadSourcePosition position)
    {
        BadObject left = leftRef.Dereference();
 
        if (left.HasProperty(BadStaticKeys.PRE_DECREMENT_OPERATOR_NAME, context?.Scope))
        {
            foreach (BadObject o in ExecuteOperatorOverride(
                         left,
                         context!,
                         BadStaticKeys.PRE_DECREMENT_OPERATOR_NAME,
                         position
                     ))
            {
                yield return o;
            }
        }
        else
        {
            yield return Decrement(leftRef, position);
        }
    }
}