Example #1
0
        /// <summary>
        /// Creates nodes in the trie to capture all the don't care (unbound) locations in the pattern.
        /// </summary>
        private ShapeNode CreateDontCareNodes()
        {
            int       i;
            bool      isExpanded;
            ShapeNode n;

            ShapeNode[] children;
            return(Pattern.Compute <ShapeNode>(
                       (x, s) => x.Groundness == Groundness.Variable ? x.Args : null,
                       (x, ch, s) =>
            {
                if (x.Symbol.Arity == 0)
                {
                    if (Executer.IsUnboundPatternVariable(x))
                    {
                        return new ShapeNode(true);
                    }
                    else
                    {
                        return null;
                    }
                }

                Contract.Assert(x.Symbol.IsDataConstructor);
                isExpanded = false;
                foreach (var m in ch)
                {
                    if (m != null)
                    {
                        isExpanded = true;
                        break;
                    }
                }

                if (!isExpanded)
                {
                    return null;
                }

                children = new ShapeNode[x.Symbol.Arity];
                i = 0;
                foreach (var m in ch)
                {
                    children[i++] = m;
                }

                n = new ShapeNode();
                n.AddRefinement((UserSymbol)x.Symbol, children);
                return n;
            }));
        }