AIMA.Core.Logic.FOL.KB.Data.Chain.getHead C# (CSharp) Method

        public Literal getHead()
        {
            if (0 == literals.Count)
            {
                return null;
            }
            return literals[0];
        }

        public Chain addToIndex(Chain c)
        {
            Chain added = null;
            Literal head = c.getHead();
            if (null != head)
            {
                Dictionary<String, List<Chain>> toAddTo = null;
                if (head.isPositiveLiteral())
                {
                    toAddTo = posHeads;
                }
                else
                {
                    toAddTo = negHeads;
                }

                String key = head.getAtomicSentence().getSymbolicName();
                List<Chain> farParents = toAddTo[key];
                if (null == farParents)
                {
                    farParents = new List<Chain>();
                    toAddTo.Add(key, farParents);
                }

                added = c;
                farParents.Add(added);
            }
            return added;
        }