StepNode.cs

using System.Collections.Generic;
using System.Linq;
using Ara3D.Utils;

namespace Ara3D.StepParser
{

    public class StepNode
    {
        public readonly StepGraph Graph;
        public readonly StepInstance Entity;

        public StepNode(StepGraph g, StepInstance e)
        {
            Graph = g;
            Entity = e;
        }

        public List<StepNode> Nodes { get; } = new();

        private void AddNodes(StepValue value)
        {
            if (value is StepId id)
            {
                var n = Graph.GetNode(id.Id);
                Nodes.Add(n);
            }
            else if (value is StepList agg)
            {
                foreach (var v in agg.Values)
                    AddNodes(v);
            }
        }

        public void Init()
        {
            foreach (var a in Entity.AttributeValues)
                AddNodes(a);
        }

        public override string ToString()
            => Entity.ToString();

        public string ToGraph(HashSet<StepNode> prev = null)
        {
            prev ??= new HashSet<StepNode>();
            if (prev.Contains(this))
                return "_";
            var nodeStr = Nodes.Select(n => n.ToGraph(prev)).JoinStringsWithComma();
            return $"{EntityType}({nodeStr})";
        }

        public string EntityType
            => Entity.EntityType;

        public string QuickHash()
            => $"{EntityType}:{Nodes.Count}";
    }
}