BadReturnExpression.cs

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using BadScript2.Common;
using BadScript2.Optimizations.Folding;
using BadScript2.Runtime;
using BadScript2.Runtime.Error;
using BadScript2.Runtime.Objects;
using BadScript2.Runtime.Objects.Types;
 
namespace BadScript2.Parser.Expressions.ControlFlow;
 
public class BadReturnExpression : BadExpression
{
    public BadReturnExpression(BadExpression? right, BadSourcePosition position, bool isRefReturn) : base(
        false,
        position
    )
    {
        Right = right;
        IsRefReturn = isRefReturn;
    }
 
    public bool IsRefReturn { get; }
 
    public BadExpression? Right { get; private set; }
 
    public void SetRight(BadExpression? expr)
    {
        Right = expr;
    }
 
    public override IEnumerable<BadExpression> GetDescendants()
    {
        if (Right == null)
        {
            yield break;
        }
 
        foreach (BadExpression right in Right.GetDescendantsAndSelf())
        {
            yield return right;
        }
    }
 
    public override void Optimize()
    {
        if (Right != null)
        {
            Right = BadConstantFoldingOptimizer.Optimize(Right);
        }
    }
 
    protected override IEnumerable<BadObject> InnerExecute(BadExecutionContext context)
    {
        BadObject value = BadObject.Null;
 
        if (Right == null)
        {
            if (context.Scope.FunctionObject != null &&
                context.Scope.FunctionObject.ReturnType == BadVoidPrototype.Instance)
            {
                context.Scope.SetReturnValue(BadVoidPrototype.Object);
            }
            else
            {
                context.Scope.SetReturnValue(value);
            }
 
            yield return value;
            yield break;
        }
 
        foreach (BadObject obj in Right.Execute(context))
        {
            value = obj;
 
            yield return obj;
        }
 
        if (!IsRefReturn)
        {
            value = value.Dereference();
        }
 
        if (context.Scope.FunctionObject != null && 
            context.Scope.FunctionObject.ReturnType == BadVoidPrototype.Instance)
        {
            if (!context.Scope.FunctionObject.IsSingleLine)
            {
                throw BadRuntimeException.Create(context.Scope, "Cannot return a value from a void function", Position);
            }
            context.Scope.SetReturnValue(BadVoidPrototype.Object);
            yield break;
        }
        
        context.Scope.SetReturnValue(value);
 
        yield return value;
    }
 
    public override string ToString()
    {
        return "return " + (Right?.ToString() ?? "");
    }
}