public ProductionExpressionBuilder(string str)
{
expression = new ProductionExpression()
{
TypeConventer.ToTerminal(str)
};
}
private void getFollow()
{
Productions[0].Left.Follow.Add(TypeConventer.ToTerminal(Tokens.LexEnd));
while (true)
{
bool loop = false;
for (var i = 0; i < Productions.Count; i++)
{
var left = Productions[i].Left;
var right = Productions[i].Right;
foreach (var proe in right)
{
var flag = true;
for (var j = proe.Count - 1; j >= 0; j--)
{
if (proe[j] is NonTerminal nontJ)
{
int x = vndic[nontJ];
if (flag)
{
int before = nontJ.Follow.Count;
nontJ.Follow.UnionWith(left.Follow);
if (!Productions[x].HasEpsilonExpression)
{
flag = false;
}
int after = nontJ.Follow.Count;
if (after > before)
{
loop = true;
}
}
for (int k = j + 1; k < proe.Count; k++)
{
if (proe[k] is NonTerminal nontK)
{
var from = nontK.First;
var to = nontJ.Follow;
int before = to.Count;
foreach (var it1 in from)
{
if (it1 != Terminal.Epsilon)
{
to.Add(it1);
}
}
int after = to.Count;
if (after > before)
{
loop = true;
}
if (!Productions[vndic[nontK]].HasEpsilonExpression)
{
break;
}
}
else if (proe[k] is Terminal termK)
{
int before = nontJ.Follow.Count;
nontJ.Follow.Add(termK);
int after = nontJ.Follow.Count;
if (after > before)
{
loop = true;
}
break;
}
else
{
continue;
}
}
}
else
{
flag = false;
}
}
}
}
if (!loop)
{
break;
}
}
}
public void Append(string str)
{
expression.Add(TypeConventer.ToTerminal(str));
}
