//添加到符号表中
public void add(symlist sym)
{
syntax_Analysis sa = compiler.sa;
if (sa.level > point)
{
point++;
dx[point] = dx[point - 1];
}
else if (sa.level < point)
{
//int delnum = dx[point] - dx[point - 1];
//for (int i = 0; i < delnum; i++)
// stable.RemoveAt(stable.Count - 1);
//point--;
}
dx[point]++;
record re = new record();
re.name = compiler.la.word;
if (sym == symlist.constsym)
{
re.kind = "constant";
re.val = compiler.la.num;
stable.Add(re);
}
else if (sym == symlist.varsym)
{
re.kind = "variable";
re.level = sa.level;
//获取地址还没写re.adr =
re.adr = compiler.sa.getadd();
stable.Add(re);
}
else if (sym == symlist.proceduresym)
{
re.kind = "procedure";
re.level = sa.level;
stable.Add(re);
}
}
//<表达式> ::= [+|-]<项>{<加法运算符><项>}
public void expression(List <symlist> followlst)
{
Pcode pc = compiler.pc;
List <symlist> nextlst = new List <symlist>();
nextlst.AddRange(followlst);
nextlst.Add(symlist.plus);
nextlst.Add(symlist.minus);
symlist symm = sym;
if (sym == symlist.minus || sym == symlist.plus)
{
getsym();
item(nextlst);
if (symm == symlist.minus)//取反
{
pc.gen("OPR", 0, 1);
}
}
else
{
item(nextlst);
}
while (sym == symlist.minus || sym == symlist.plus)
{
symm = sym;
getsym();
item(nextlst);
if (symm == symlist.plus)
{
pc.gen("OPR", 0, 2);
}
else
{
pc.gen("OPR", 0, 3);
}
}
}
//<条件> ::= <表达式><关系运算符><表达式>|odd<表达式>
public void ifstatement(List <symlist> followlst)
{
Pcode pc = compiler.pc;
List <symlist> nextlst = new List <symlist>();
List <symlist> n2 = new List <symlist>();
Error er = compiler.error;
nextlst.Add(symlist.equality);
nextlst.Add(symlist.LessThan);
nextlst.Add(symlist.LessThanE);
nextlst.Add(symlist.MoreThan);
nextlst.Add(symlist.MoreThanE);
nextlst.Add(symlist.inequality);
if (sym != symlist.oddsym)
{
n2.AddRange(followlst);
n2.AddRange(nextlst);
expression(n2);
if (!nextlst.Contains(sym))
{
er.adderror(20);
}
else
{
symlist symm = sym;
getsym();
expression(followlst);
switch (symm)
{
case symlist.equality:
pc.gen("OPR", 0, 8);
break;
case symlist.LessThan:
pc.gen("OPR", 0, 13);
break;
case symlist.LessThanE:
pc.gen("OPR", 0, 10);
break;
case symlist.MoreThan:
pc.gen("OPR", 0, 12);
break;
case symlist.MoreThanE:
pc.gen("OPR", 0, 11);
break;
case symlist.inequality:
pc.gen("OPR", 0, 9);
break;
}
}
}
else if (sym == symlist.oddsym)
{
getsym();
expression(followlst);
pc.gen("OPR", 0, 6);
}
}
public void getsym()
{
sym = compiler.la.getsym();
}
//int isconst(string word)
//{
// for (int i = 0; i < (word.Length); i++)
// {
// if (word[i] > '9' || word[i] < '0') return 0;
// }
// return 33;
//}
//int issame(char f, char s)
//{
// string str = "" + f + s;
// if(isoperator(str)>0)
// {
// return 1;
// }
// bool a = ((f >= '0' && f <= '9') || isletter(f)) ? true : false;
// bool b = ((s >= '0' && s <= '9') || isletter(s)) ? true : false;
// if (a == b)
// return 1;
// return 0;
//}
//bool isiden(string word)
//{
// if (!isletter(word[0])) return false;
// for (int i = 1; i < word.Length; i++)
// {
// if (issame(word[i], word[i])==0) return false;
// }
// return true;
//}
//bool typeword(string word)
//{
// int a;
// if ((a = isreserveword(word))>0) { syn = a; return true; }
// //else if(Isdelimiter(word)){syn = 2;}
// else if ((a = isconst(word))>0) { syn = a; return true; }
// else if ((a = isoperator(word))>0) { syn = a; return true; }
// //普通标识符
// else if (isiden(word)) { syn = 34; return true; }
// else
// {
// //Console.WriteLine(word + "compile error");
// return false;
// }
//}
//public string print(string word)
//{
// string output="";
// if (syn < 17)
// {
// output = string.Format("{0,-12}", word) + string.Format("{0,-12}", "关键字") + string.Format("{0,-12}", word) + '\r' + '\n';
// }
// if(syn>=17&&syn<22)
// {
// output = string.Format("{0,-12}", word) + string.Format("{0,-12}", "分界符") + string.Format("{0,-12}", word) + '\r' + '\n';
// }
// if (syn >= 22 && syn <29)
// {
// output = string.Format("{0,-12}", word) + string.Format("{0,-12}", "单字符运算符") + string.Format("{0,-12}", word) + '\r' + '\n';
// }
// if (syn >= 29 && syn < 33)
// {
// output = string.Format("{0,-12}", word) + string.Format("{0,-12}", "双字符运算符") + string.Format("{0,-12}", word) + '\r' + '\n';
// }
// if (syn ==34)
// {
// output = string.Format("{0,-12}", word) + string.Format("{0,-12}", "标识符") + string.Format("{0,-12}", word) + '\r' + '\n';
// }
// return output;
//}
public symlist getsym()
{
Error er = compiler.error;
int syn_num;
//word = "";
if (i > code.Length - 1)
{
return(symlist.end);
}
char c = code[i];
//跳过空格
while (c == ' ' || c == '\n' || c == '\t' || c == '\r')
{
if (c == '\n')
{
line++;
}
i++;
if (i > code.Length - 1)
{
return(symlist.end);
}
c = code[i];
}
//标识符
if (isletter(c))
{
word = "";
do
{
word += c;
i++;
if (i > code.Length - 1)
{
return(symlist.end);
}
c = code[i];
} while (isletter(c) || isnum(c));
syn_num = isreserveword(word);
if (syn_num > 0)
{
sym = (symlist)syn_num;
}
else
{
return(symlist.iden);
}
}
//数字
else if (isnum(c))
{
chnum = "";
do
{
chnum += c;
i++;
if (i > code.Length - 1)
{
return(symlist.end);
}
c = code[i];
} while (isnum(c));
try
{
num = Convert.ToInt32(chnum);
}
catch (OverflowException e)
{
er.adderror(31);
num = 0;
}
sym = symlist.number;
}
//分界符
else if ((syn_num = isdelimiter(c)) > 0)
{
sym = (symlist)syn_num;
i++;
}
//三个双目操作
else if (c == ':')
{
i++;
if (i > code.Length - 1)
{
return(symlist.end);
}
c = code[i];
if (c == '=')
{
sym = symlist.becomes;
}
else
{
sym = symlist.nul;
}
i++;
}
else if (c == '<') //"<>",">=","<=",":="
{
i++;
if (i > code.Length - 1)
{
return(symlist.end);
}
c = code[i];
if (c == '>')
{
sym = symlist.inequality;
}
else if (c == '=')
{
sym = symlist.LessThan;
}
else
{
sym = symlist.LessThanE; i--;
}
i++;
}
else if (c == '>')
{
i++;
if (i > code.Length - 1)
{
return(symlist.end);
}
c = code[i];
if (c == '=')
{
sym = symlist.MoreThan;
}
else
{
sym = symlist.MoreThanE; i--;
}
i++;
}
//单目操作
else if ((syn_num = isoperator(c)) > 0)
{
sym = (symlist)syn_num;
i++;
}
return(sym);
}
