public static string DOUBLE_MARKS = "dD"; //double的结尾标志 public Element Read(ExpressionReader sr) { int index = sr.GetCurrentIndex(); string s = string.Empty; int b = -1; while ((b = sr.Read()) != -1) { char c = (char)b; if (NUMBER_CHARS.IndexOf(c) == -1) { if (LONG_MARKS.IndexOf(c) >= 0) { if (s.IndexOf(".") >= 0) {//有小数点 throw new FormatException("long类型不能有小数点"); } return(new Element(s.ToString(), index, ElementType.LONG)); } else if (FLOAT_MARKS.IndexOf(c) >= 0) { CheckDecimal(s); return(new Element(s.ToString(), index, ElementType.FLOAT)); } else if (DOUBLE_MARKS.IndexOf(c) >= 0) { CheckDecimal(s); return(new Element(s.ToString(), index, ElementType.DOUBLE)); } else { sr.Reset(); if (s.IndexOf(".") >= 0) {//没有结束标志,有小数点,为double CheckDecimal(s); return(new Element(s.ToString(), index, ElementType.DOUBLE)); } else {//没有结束标志,无小数点,为int return(new Element(s.ToString(), index, ElementType.INT)); } } } s += c; sr.Mark(0); } //读到结未 if (s.IndexOf(".") >= 0) {//没有结束标志,有小数点,为double CheckDecimal(s); return(new Element(s.ToString(), index, ElementType.DOUBLE)); } else {//没有结束标志,无小数点,为int return(new Element(s.ToString(), index, ElementType.INT)); } }
/// <summary> /// 根据流开头构造不同的词元读取 流应该非空格开头 /// </summary> /// <param name="reader"></param> /// <returns></returns> public static IElementReader CreateElementReader(ExpressionReader reader) { //读一个char reader.Mark(0); int b = reader.Read(); reader.Reset(); if (b != -1) { char c = (char)b; try { if (c == StringTypeReader.START_MARK) {//"开头,构造字符串读取器 return(new StringTypeReader()); } else if (c == DateTypeReader.START_MARK) {//[开头,构造日期读取器 return(new DateTypeReader()); } else if (c == FunctionTypeReader.START_MARK) {//$开头,构造函数读取器 return(new FunctionTypeReader()); } else if (SplitorTypeReader.SPLITOR_CHAR.IndexOf(c) >= 0) {//如果是分隔符,构造分隔符读取器 return(new SplitorTypeReader()); } else if (NumberTypeReader.NUMBER_CHARS.IndexOf(c) >= 0) {//以数字开头,构造数字类型读取器 return(new NumberTypeReader()); } else if (OperatorTypeReader.IsOperatorStart(reader)) {//如果前缀是运算符,构造运算符读取器 return(new OperatorTypeReader()); } else { return(new VariableTypeReader());//否则构造一个变量读取器 } } catch (Exception e) { throw new FormatException("", e); } } else { throw new FormatException("流已结束"); } }
public Element Read(ExpressionReader sr) { int index = sr.GetCurrentIndex(); var sb = new StringBuilder(); int b = sr.Read(); if (b == -1) { throw new FormatException("表达式已结束"); } char c = (char)b; sb.Append(c); if (IsOperatorWord(sb.ToString())) { if (sb.Length == 1) {//两个符号的运算符优先,如<=,不应该认为是<运算符 sr.Mark(0); b = sr.Read(); if (b != -1) { if (IsOperatorWord(sb.ToString() + (char)b)) { return(new Element(sb.ToString() + (char)b, index, ElementType.OPERATOR)); } } sr.Reset(); } return(new Element(sb.ToString(), index, ElementType.OPERATOR)); } while ((b = sr.Read()) != -1) { c = (char)b; sb.Append(c); if (IsOperatorWord(sb.ToString())) { return(new Element(sb.ToString(), index, ElementType.OPERATOR)); } if (VariableTypeReader.STOP_CHAR.IndexOf(c) >= 0) {//单词停止符 throw new FormatException("不是有效的运算符:" + sb.ToString()); } } throw new FormatException("不是有效的运算符结束"); }
public static char END_MARK = '('; //函数结束 /** * 从流中读取函数类型的ExpressionToken * @param sr * @return * @throws FormatException * @throws IOException */ public Element Read(ExpressionReader sr) { int index = sr.GetCurrentIndex(); var sb = new StringBuilder(); int b = sr.Read(); if (b == -1 || b != START_MARK) { throw new FormatException("不是有效的函数开始"); } bool readStart = true; while ((b = sr.Read()) != -1) { char c = (char)b; if (c == END_MARK) { if (sb.Length == 0) { throw new FormatException("函数名称不能为空"); } sr.Reset(); return(new Element(sb.ToString(), index, ElementType.FUNCTION)); } //if (!Character.isJavaIdentifierPart(c)) { // throw new FormatException("名称不能为非法字符:" + c); //} if (readStart) { //if (!Character.isJavaIdentifierStart(c)) { // throw new FormatException("名称开头不能为字符:" + c); //} readStart = false; } sb.Append(c); sr.Mark(0); } throw new FormatException("不是有效的函数结束"); }
private string ReadWord(ExpressionReader sr) { var sb = new StringBuilder(); bool readStart = true; int b = -1; while ((b = sr.Read()) != -1) { char c = (char)b; if (STOP_CHAR.IndexOf(c) >= 0 && !readStart) {//单词停止符,并且忽略第一个字符 sr.Reset(); return(sb.ToString()); } if (readStart) { readStart = false; } sb.Append(c); sr.Mark(0); } return(sb.ToString()); }
/// <summary> /// 测试是否为运算符 /// </summary> /// <param name="sr"></param> /// <returns></returns> public static bool IsOperatorStart(ExpressionReader sr) { sr.Mark(0); try { var sb = new StringBuilder(); int b = sr.Read(); if (b == -1) { return(false); } char c = (char)b; sb.Append(c); if (IsOperatorWord(sb.ToString())) { return(true); } while ((b = sr.Read()) != -1) { c = (char)b; sb.Append(c); if (IsOperatorWord(sb.ToString())) { return(true); } if (VariableTypeReader.STOP_CHAR.IndexOf(c) >= 0) {//单词停止符 return(false); } } return(false); } finally { sr.Reset(); } }