/// <summary>
/// 检查是否为保留字
/// </summary>
/// <param name="test"></param>
/// <returns></returns>
private int isReserved(string test)
{
for (int i = 0; i < reservedSym.Count; i++)
{
symbol_reserved sr = (symbol_reserved)(reservedSym[i]);
if (sr.reserved == test)
{
return(i);
}
}
return(-1);
}
/// <summary>
/// 获取单词
/// </summary>
/// <returns></returns>
public symbol getSymbol()
{
ErrorHandle error = compiler.EH;
int maxVarLen = (int)constnum.MAX_VAR_LEN;
symbol sym;
int k, p, num;
LSymLine = lineNum;
while (ch == (int)' ' || ch == (int)'\r' || ch == (int)'\n' || ch == (int)'\t')
{
if (ch == (int)'\n')
{
lineNum++;
}
ch = sourceCode.Read();
}
//读取标识符
if ((ch >= (int)'a' && ch <= (int)'z') || (ch >= (int)'A' && ch <= (int)'Z'))
{
k = 0;
List <char> name = new List <char>();
do
{
if (k < maxVarLen)
{
name.Add((char)ch);
}
k++;
ch = sourceCode.Read();
} while ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9'));
tname = new string(name.ToArray());
p = isReserved(tname);
if (p >= 0)
{
symbol_reserved sr = (symbol_reserved)(reservedSym[p]);
sym = sr.sym;
}
else
{
sym = symbol.ident;
}
}
//读取数字
else if ((ch >= (int)'0' && ch <= (int)'9'))
{
k = 0;
num = 0;
sym = symbol.number;
do
{
num = num * 10 + (ch - (int)'0');
k++;
ch = sourceCode.Read();
} while ((ch >= (int)'0' && ch <= (int)'9'));
if (k > (int)constnum.MAX_INT_LEN)
{
error.adderr(30);
}
if (num > (int)constnum.MAX_INT)
{
error.adderr(31);
num = 0;
}
tnumber = num;
}
//读取其他
else if (ch == (int)':')
{
ch = sourceCode.Read();
if (ch == (int)'=')
{
sym = symbol.becomes;
ch = sourceCode.Read();
}
else
{
sym = symbol.nul;
}
}
else if (ch == (int)'>')
{
ch = sourceCode.Read();
if (ch == (int)'=')
{
sym = symbol.MoreThanE;
ch = sourceCode.Read();
}
else
{
sym = symbol.MoreThan;
}
}
else if (ch == (int)'<')
{
ch = sourceCode.Read();
if (ch == (int)'=')
{
sym = symbol.LessThanE;
ch = sourceCode.Read();
}
else if (ch == (int)'>')
{
sym = symbol.inequality;
ch = sourceCode.Read();
}
else
{
sym = symbol.LessThan;
}
}
else
{
switch (ch)
{
case (int)'+': sym = symbol.plus;
break;
case '-': sym = symbol.minus;
break;
case (int)'*': sym = symbol.times;
break;
case (int)'/': sym = symbol.division;
break;
case (int)'(': sym = symbol.LParenthesis;
break;
case (int)')': sym = symbol.RParenthesis;
break;
case (int)';': sym = symbol.semicolon;
break;
case (int)',': sym = symbol.comma;
break;
case (int)'.': sym = symbol.period;
break;
//case (int)'#': sym = symbol.inequality;
// break;
case (int)'=': sym = symbol.equality;
break;
case -1: sym = symbol.endfile;
break;
default: sym = symbol.nul;
break;
}
ch = sourceCode.Read();
}
return(sym);
}