Antlr4.Analysis.LeftFactoringRuleTransformer.ExpandOptionalQuantifiersForBlock C# (CSharp) Method

        protected virtual bool ExpandOptionalQuantifiersForBlock(GrammarAST block, bool variant)
        {
            IList<GrammarAST> children = new List<GrammarAST>();
            for (int i = 0; i < block.ChildCount; i++)
            {
                GrammarAST child = (GrammarAST)block.GetChild(i);
                if (child.Type != ANTLRParser.ALT)
                {
                    children.Add(child);
                    continue;
                }

                GrammarAST expandedAlt = ExpandOptionalQuantifiersForAlt(child);
                if (expandedAlt == null)
                {
                    return false;
                }

                children.Add(expandedAlt);
            }

            GrammarAST newChildren = (GrammarAST)adaptor.Nil();
            newChildren.AddChildren(children);
            block.ReplaceChildren(0, block.ChildCount - 1, newChildren);
            block.FreshenParentAndChildIndexesDeeply();

            if (!variant && block.Parent is RuleAST)
            {
                RuleAST ruleAST = (RuleAST)block.Parent;
                string ruleName = ruleAST.GetChild(0).Text;
                Rule r = _rules[ruleName];
                IList<GrammarAST> blockAlts = block.GetAllChildrenWithType(ANTLRParser.ALT);
                r.numberOfAlts = blockAlts.Count;
                r.alt = new Alternative[blockAlts.Count + 1];
                for (int i = 0; i < blockAlts.Count; i++)
                {
                    r.alt[i + 1] = new Alternative(r, i + 1);
                    r.alt[i + 1].ast = (AltAST)blockAlts[i];
                }
            }

            return true;
        }