/// <summary>
/// 构造函数
/// </summary>
public SymbolTable(PL0Compiler C)
{
this.lev = 0;
this.tx[0] = 0;
SymTabItem nul = new SymTabItem();
nul.name = "";
SymTable.Add(nul);
this.compiler = C;
}
/// <summary>
/// 字符表登录函数
/// </summary>
/// <param name="K">类型</param>
public void Enter(ObjectK K)
{
GrammarAndSemanticAna GS = compiler.GSA;
if (GS.getLevel() > lev)
{
lev++;
tx[lev] = tx[lev - 1];
}
else if (GS.getLevel() < lev)
{
lev--;
}
tx[lev]++;
SymTabItem item = new SymTabItem();
item.kind = K;
item.name = compiler.SA.tname;
switch (K)
{
case ObjectK.constant:
item.value = compiler.SA.tnumber;
SymTable.Add(item);
break;
case ObjectK.variable:
item.level = compiler.GSA.getLevel();
item.address = compiler.GSA.getAddress();
SymTable.Add(item);
break;
case ObjectK.procedure:
item.level = compiler.GSA.getLevel();
SymTable.Add(item);
break;
}
}
/// <summary>
/// 因子模块
/// </summary>
/// <param name="factSym">开始与后继符号集</param>
private void factor(SymbolSet factSym)
{
int i;
ErrorHandle err = compiler.EH;
SymbolTable table = compiler.ST;
PCodeGenetate pCode = compiler.PCG;
SymbolSet sfb = new SymbolSet();
sfb.AddRange(factorbegs.SymSet);
ErrorTest(sfb, factSym, 24);
while (factorbegs.isInSet(sym))
{
switch (sym)
{
case symbol.ident:
i = table.getPosition(compiler.SA.tname);
if (i == 0)
{
err.adderr(11);
}
else
{
SymTabItem STI = table.SymTable[i];
switch (STI.kind)
{
case ObjectK.constant:
pCode.Gen(oprCode.lit, 0, STI.value);
break;
case ObjectK.variable:
int fa = level - STI.level;
int la = STI.address;
pCode.Gen(oprCode.lod, fa, la);
break;
case ObjectK.procedure:
err.adderr(21);
break;
}
}
getsym();
break;
case symbol.number:
pCode.Gen(oprCode.lit, 0, compiler.SA.tnumber);
getsym();
break;
case symbol.LParenthesis:
getsym();
factSym.Add(symbol.RParenthesis);
expression(factSym);
if (sym == symbol.RParenthesis)
{
getsym();
}
else
{
err.adderr(22);
}
break;
}
ErrorTest(factSym, factorbegs, 23);
}
}