private void BuildSLRDFA()
{
SLRDFASTAT stat;
stats = new List <SLRDFASTAT>();
stat = new SLRDFASTAT(null, "");
stat.State_Number = 0;
//Adding start'->. <start> as the first state
SLRDFASTAT.Statement statem = new SLRDFASTAT.Statement();
statem.isCore = true;
statem.Left = "start'";
statem.Right = new RightSide()
{
Right = "<start>", Left = "start'", isEpsilon = false
};
statem.Right.AddFollow("$");
//statem.DotIndex = 0; it is zero by defualt
foreach (var fr in grammer["start"].Firsts)
{
statem.Right.AddFirst(fr);
}
stat.AddStatement(statem);
recursiveStateBuilder(stat, null);
}
/// <summary>
/// Builds the LR DFA states recursivly
/// </summary>
/// <param name="current">Current state</param>
/// <param name="parent">Parent</param>
/// <returns></returns>
private SLRDFASTAT recursiveStateBuilder(SLRDFASTAT current, SLRDFASTAT parent)
{
string afterDot = "";
int index = 0;
while (true)
{
if (index == current.Statements.Count)
{
break;
}
int Dot = current.Statements[index].DotIndex;
if (!current.Statements[index].DotIsAtEnd)
{
afterDot = current.Statements[index].Right.words[Dot];
}
else
{
index++;
continue;
}
if (afterDot == "epsilon")
{
//Since epsilon is not a token we always just pass the dot over epsilon
current.Statements[index].DotIndex++;
continue;
}
SLRDFASTAT.Statement statem = new SLRDFASTAT.Statement();
statem.Left = current.Statements[index].Left;
statem.Right = current.Statements[index].Right;
statem.DotIndex = current.Statements[index].DotIndex;
statem.isCore = true;
if (current.next_pointers.ContainsKey(afterDot))
{
if (!current.next_pointers[afterDot].Statements.Contains(statem))
{
current.next_pointers[afterDot].Statements.Add(statem);
}
}
else
{
SLRDFASTAT newStat = new SLRDFASTAT(current, afterDot);
newStat.AddStatement(statem);
current.next_pointers.Add(afterDot, newStat);
}
//Creating prediction set
if (Parser.isRule(afterDot))
{
foreach (var right in grammer[Parser.returnRuleName(afterDot)].Rights)
{
statem = new SLRDFASTAT.Statement();
statem.Left = afterDot;
statem.Right = right;
statem.isCore = false;
bool include = false;
foreach (var cr in current.Statements)
{
if (cr.Presentation == statem.Presentation && cr.DotIndex == statem.DotIndex)
{
include = true;
}
}
if (!include)
{
current.AddStatement(statem);
}
}
}
if (index == current.Statements.Count - 1)
{
break;
}
index++;
}
foreach (var st in stats)
{
//we will add this state to list if it is not repetetive
if (statsAreEqual(st, current))
{
current.State_Number = st.State_Number;
st.parent.AddRange(current.parent);
return(current);
}
}
current.State_Number = stat_number++;
stats.Add(current);
for (int j = 0; j < current.next_pointers.Count; j++)
{
string key = current.next_pointers.Keys.ElementAt(j);
foreach (var stat in current.next_pointers[key].Statements)
{
stat.DotIndex++;
}
current.next_pointers[key] = recursiveStateBuilder(current.next_pointers[key], current);
}
return(current);
}