protected void CheckEpsilonInRules()
{
bool bChanged = true;
while (bChanged)
{
bChanged = false;
for (int i = 0; i < m_Rules.Count; i++)
{
bool EpsFree = false;
BNFRule bnfRl = (BNFRule)m_Rules[i];
RuleStart strt = bnfRl.GetStart();
if (strt != null)
{
RuleElement re = strt.GetNext();
EpsFree = BetaTotalRuleEpsFree(re);
}
if (strt.GetRuleConnect().EpsilonFree != EpsFree)
{
bChanged = true;
}
strt.GetRuleConnect().EpsilonFree = EpsFree;
}
}
}
protected void GenerateAllFirstSets()
{
bool bChanged = true;
while (bChanged)
{
bChanged = false;
for (int i = 0; i < m_Rules.Count; i++)
{
MyArrayList FirstSet = new MyArrayList();
BNFRule bnfRl = (BNFRule)m_Rules[i];
RuleStart strt = bnfRl.GetStart();
if (strt != null)
{
RuleElement re = strt.GetNext();
FirstSet = BetaTotalRuleFirstSet(re);
}
int FrstSize = 0;
if (strt.GetRuleConnect().FirstSet != null)
{
FrstSize = strt.GetRuleConnect().FirstSet.Count;
}
strt.GetRuleConnect().FirstSet = ParseHelper.UnionSet(strt.GetRuleConnect().FirstSet, FirstSet);
FrstSize = strt.GetRuleConnect().FirstSet.Count - FrstSize;
if (FrstSize != 0)
{
bChanged = true;
}
}
}
}
/// <summary>
/// Find all Tokens inside Rule
/// </summary>
/// <param name="Token">Token String to find</param>
/// <returns></returns>
public MyArrayList FindToken(string Token)
{
MyArrayList sr = new MyArrayList();
if (Start != null)
{
RuleElement pos = Start.GetNext();
while (pos != null)
{
if (pos.GetToken().Equals(Token))
{
sr.Add(pos);
}
pos = pos.GetNext();
}
}
return(sr);
}
protected virtual MyArrayList GenerateFirstSet(RuleStart rs)
{
MyArrayList res = new MyArrayList();
RuleElement re = null;
if (rs != null)
{
re = rs.GetNext();
}
else
{
return(null);
}
while (re != null)
{
if (re.GetToken().Equals(""))
{
re = re.GetNext();
}
else
{
if (re.IsTerminal())
{
res.Add(re);
return(res);
}
else
{
RuleToken rt = (RuleToken)re;
RuleStart conStr = GoToFirstStartRule(rt.GetConnected());
MyArrayList res2 = null;
while (conStr != null)
{
res2 = GenerateFirstSet(conStr);
res = ParseHelper.UnionSet(res, res2);
conStr = conStr.GetAlternate();
}
if (TotalRuleEpsFree(rt.GetConnected()))
{
return(res);
}
else
{
re = re.GetNext();
}
}
}
}
return(res);
}
private void EleminateDirectLeftRecursion(RuleStart strt)
{
string ElemStartTkn = "";
if (strt != null)
{
ElemStartTkn = FindUnusedToken(strt.GetToken());
}
while (strt != null)
{
if (IsRuleLeftRekursiv(strt))
{
RuleElement re = strt.GetNext();
if (re != null)
{
strt.SetNext(re.GetNext());
re = GotoLastRule(strt);
re.SetNext(new RuleToken(ElemStartTkn, strt));
strt.SetToken(ElemStartTkn);
}
BNFRule bnfRl = new BNFRule(m_Rules.Count);
bnfRl.SetStart(ElemStartTkn);
bnfRl.GetStart().SetNext(new RuleEpsilon(bnfRl.GetStart()));
m_Rules.Add(bnfRl);
}
else
{
RuleElement re = strt.GetNext();
if (re != null)
{
re = GotoLastRule(strt);
re.SetNext(new RuleToken(ElemStartTkn, strt));
}
}
strt = strt.GetAlternate();
}
}
private string[] Rule2String(RuleStart rs)
{
MyArrayList elements = new MyArrayList();
if (rs != null)
{
RuleElement re = rs.GetNext();
while (re != null)
{
elements.Add(re.GetToken());
re = re.GetNext();
}
}
return((string[])elements.ToArray(typeof(string)));
}
private bool IsRuleLeftRekursiv(RuleStart rs)
{
RuleElement re = rs.GetNext();
if (re != null)
{
string StartToken = rs.GetToken();
string FirstToken = re.GetToken();
if (StartToken.Equals(FirstToken))
{
return(true);
}
}
return(false);
}
private MyArrayList Rules2Array(RuleStart rs)
{
MyArrayList invRules = new MyArrayList();
if (rs != null)
{
RuleElement re = rs.GetNext();
while (re != null)
{
invRules.Add(re);
re = re.GetNext();
}
}
return(invRules);
}
protected virtual bool RuleIsEpsilonFree(RuleStart rs)
{
RuleElement re = null;
if (rs != null)
{
re = rs.GetNext();
}
else
{
return(false);
}
while (re != null)
{
if (re.IsTerminal())
{
rs.GetRuleConnect().EpsilonFree = true;
return(true);
}
else
{
if (re.GetToken().Equals(""))
{
rs.GetRuleConnect().EpsilonFree = false;
return(false);
}
else
{
RuleToken rt = (RuleToken)re;
bool res = RuleIsEpsilonFree(rt.GetConnected());
if (res)
{
rs.GetRuleConnect().EpsilonFree = res;
return(res);
}
else
{
re = re.GetNext();
}
}
}
}
rs.GetRuleConnect().EpsilonFree = false;
return(false);
}
