Catrobat.IDE.Core.Formulas.FormulaInterpreter.Interpret2 C# (CSharp) Метод

        private FormulaTree Interpret2(IList<IFormulaToken> tokens)
        {
            // valid tokens
            if (tokens == null)
            {
                SetParsingError(null, AppResourcesHelper.Get("FormulaInterpreter_NullOrEmpty"));
                return null;
            }

            // interpret syntax
            var tokens2 = SetOrigin(tokens).ToList();
            var tokens3 = tokens2.AsEnumerable();
            tokens3 = InterpretBrackets(tokens3);
            tokens3 = InterpretNumbers(tokens3, tokens2);
            tokens3 = InterpretNonParameter(tokens3);
            tokens3 = InterpretFunctions(tokens3);
            tokens3 = InterpretMinusTokenForward(tokens3);
            tokens3 = InterpretOperators(tokens3, tokens2);
            var formula = tokens3.Cast<FormulaTree>().FirstOrDefault();
            if (IsCancellationRequested) return null;

            // valid formula
            if (formula == null)
            {
                SetParsingError(
                    source: Range.FromLength(0, tokens.Count), 
                    message: AppResourcesHelper.Get("FormulaInterpreter_NullOrEmpty"));
                return null;
            }

            // special case *) should find parsing error at *
            var formulaRange = GetOrigin(formula);
            if (formulaRange.Length < tokens.Count)
            {
                var nextIndex = formulaRange.End;
                var nextToken = tokens2.First(token => GetOrigin(token).Start == nextIndex);
                var nextParenthesis = nextToken as FormulaTokenParenthesis;
                if (nextParenthesis != null && nextParenthesis.IsClosing)
                {
                    SetParsingError(
                        source: nextParenthesis, 
                        message: AppResourcesHelper.Get("FormulaInterpreter_Brackets_UnmatchedClosingParenthesis"));
                }
                else if (nextToken is FormulaTokenParameterSeparator)
                {
                    SetParsingError(
                        source: nextToken,
                        message: AppResourcesHelper.Get("FormulaInterpreter_Brackets_NonArgumentParameterSeparator"));
                }
                else
                {
                    SetParsingError(
                        source: Range.Empty(GetOrigin(formula).End),
                        message: AppResourcesHelper.Get("FormulaInterpreter_DoubleValue"));
                }
                return null;
            }

            // interpret semantics
            try
            {
                // validate evaluation constraints like sin(True + 4)
                var isNumber = formula.IsNumber();
            }
            catch (SemanticsErrorException ex)
            {
                var selection = ex.Node == null ? Range.Empty(0) : GetOrigin(ex.Node);
                SetParsingError2(selection, ex.Message);
                return null;
            }

            return formula;
        }

        public static FormulaTree Interpret(IList<IFormulaToken> tokens, out ParsingError parsingError)
        {
            // TODO: split to InterpretNumber and InterpretLogic
            //var sw = new Stopwatch();
            //sw.Start();

            // interpret tokens
            var instance = new FormulaInterpreter();
            var result = instance.Interpret2(tokens);
            parsingError = instance.ParsingError;

            //sw.Stop();
            // Debug.WriteLine("Interpreter.Interpret needed " + sw.ElapsedMilliseconds + "ms");

            return result;
        }