string getConstantFromSimpleExpression(Dictionary <string, string> input, SimpleExpression expr) { string result = NAC; if (expr.GetType() == typeof(Int32Const)) { result = (expr as Int32Const).ToString(); } else if (expr.GetType() == typeof(Identifier)) { string var = (expr as Identifier).ToString(); if (!input.ContainsKey(var)) { input[var] = UNDEF; } result = input[var]; } return(result); }