public static void Build(GrammarTables result, Grammar grammar)
{
using (var builder = new BuildDFA())
{
builder.InternalBuild(result, grammar);
}
}
private void LoadEGT(BinaryReader reader)
{
using (EGTReader egtReader = new EGTReader(reader))
{
while (egtReader.GetNextRecord())
{
switch (egtReader.ReadRecordType())
{
case EGTRecord.Property:
GrammarProperties.SetProperty(egtReader.ReadGrammarProperty());
break;
case EGTRecord.TableCounts:
GrammarTables = egtReader.ReadGrammarTables();
break;
case EGTRecord.InitialStates:
//DFA, LALR
ushort dfaState = egtReader.ReadUInt16();
ushort lalrState = egtReader.ReadUInt16();
Debug.Assert(dfaState == 0, "The initial DFA State is not 0!");
Debug.Assert(lalrState == 0, "The initial LALR State is not 0!");
break;
case EGTRecord.Symbol:
Symbol sym = egtReader.ReadSymbol();
GrammarTables.Symbols[sym.TableIndex] = sym;
break;
case EGTRecord.Group:
Group group = egtReader.ReadGroup();
GrammarTables.Groups[group.TableIndex] = group;
break;
case EGTRecord.CharRanges:
CharacterSet charSet = egtReader.ReadCharacterSet();
GrammarTables.CharacterSets[charSet.Index] = charSet;
break;
case EGTRecord.Production:
Production prod = egtReader.ReadProduction();
GrammarTables.Productions[prod.TableIndex] = prod;
break;
case EGTRecord.DFAState:
FAState faState = egtReader.ReadFAState();
GrammarTables.FAStates[faState.TableIndex] = faState;
break;
case EGTRecord.LRState:
LRActionList actionList = egtReader.ReadLRActionList();
GrammarTables.LRActionLists[actionList.Index] = actionList;
break;
}
}
}
}
private void LoadEGT(BinaryReader reader)
{
using (EGTReader egtReader = new EGTReader(reader))
{
while (egtReader.GetNextRecord())
{
switch (egtReader.ReadRecordType())
{
case EGTRecord.Property:
GrammarProperties.SetProperty(egtReader.ReadGrammarProperty());
break;
case EGTRecord.TableCounts:
GrammarTables = egtReader.ReadGrammarTables();
break;
case EGTRecord.InitialStates:
//DFA, LALR
ushort dfaState = egtReader.ReadUInt16();
ushort lalrState = egtReader.ReadUInt16();
Debug.Assert(dfaState == 0, "The initial DFA State is not 0!");
Debug.Assert(lalrState == 0, "The initial LALR State is not 0!");
break;
case EGTRecord.Symbol:
Symbol sym = egtReader.ReadSymbol();
GrammarTables.Symbols[sym.TableIndex] = sym;
break;
case EGTRecord.Group:
Group group = egtReader.ReadGroup();
GrammarTables.Groups[group.TableIndex] = group;
break;
case EGTRecord.CharRanges:
CharacterSet charSet = egtReader.ReadCharacterSet();
GrammarTables.CharacterSets[charSet.Index] = charSet;
break;
case EGTRecord.Production:
Production prod = egtReader.ReadProduction();
GrammarTables.Productions[prod.TableIndex] = prod;
break;
case EGTRecord.DFAState:
FAState faState = egtReader.ReadFAState();
GrammarTables.FAStates[faState.TableIndex] = faState;
break;
case EGTRecord.LRState:
LRActionList actionList = egtReader.ReadLRActionList();
GrammarTables.LRActionLists[actionList.Index] = actionList;
break;
}
}
}
}
private void CheckErrorsDFA(GrammarTables result)
{
bool hasErrors = false;
if (m_dfa[result.DfaStartState].AcceptList.Count > 0)
{
hasErrors = true;
foreach (var item in m_dfa[result.DfaStartState].AcceptList)
{
Console.WriteLine($"The terminal '{item.Symbol.Name}' can be zero length.");
Console.WriteLine("The definition of this terminal allows it to contain no characters.");
}
}
if (!hasErrors)
{
foreach (var build in m_dfa)
{
if (build.AcceptList.Count >= 2)
{
hasErrors = true;
Console.WriteLine($"DFA State '{build.TableIndex}' cannot distinguish between: ");
foreach (var item in build.AcceptList)
{
Console.WriteLine($" {item.Symbol.Name}");
}
}
}
}
if (!hasErrors)
{
var symbols = new HashSet <Symbol>(result.Symbols.OfType <SymbolTerminal>().Where(s => s.Expression != null));
foreach (var build in result.DFA)
{
symbols.Remove(build.Accept);
}
foreach (var build in symbols)
{
hasErrors = true;
Console.WriteLine($"The terminal '{build.Name}' cannot be accepted by the DFA.");
}
}
if (!hasErrors)
{
Console.WriteLine("The DFA State Table was successfully created.");
Console.WriteLine($"The table contains a total of {result.DFA.Count} states.");
}
}
internal GrammarTables ReadGrammarTables()
{
ushort symbolsSize = ReadUInt16();
ushort charSetsSize = ReadUInt16();
ushort productionsSize = ReadUInt16();
ushort faStatesSize = ReadUInt16();
ushort lrActionsListsSize = ReadUInt16();
ushort groupsSize = ReadUInt16();
//Keep it for later use in addition to reading it
grammarTables = new GrammarTables(symbolsSize, charSetsSize, productionsSize,
faStatesSize, lrActionsListsSize, groupsSize);
return(grammarTables);
}
private void InternalBuild(GrammarTables result)
{
var startSymbol = m_grammar.StartSymbol;
if (ReferenceEquals(startSymbol, null))
{
throw new Exception("ERROR: Start symbol is invalid or missing");
}
Console.WriteLine("Computing LALR Tables");
SetupTempTables();
Console.WriteLine("LALR Tables Completed");
}
private void InternalBuild(GrammarTables result, Grammar grammar)
{
Console.WriteLine("Computing DFA States");
foreach (var terminal in grammar.BuildSymbols.Select(s => s.Symbol).OfType <SymbolTerminal>())
{
if (terminal.Expression == null)
{
continue;
}
var target = AddState();
var source = AddState();
foreach (Sequence sequence in terminal.Expression)
{
Automata type = sequence.CreateAutomata(this);
m_nfa[target].AddLambdaEdge(type.Head);
m_nfa[type.Tail].AddLambdaEdge(source);
m_nfa[type.Tail].AddAccept(terminal, sequence.Priority);
}
m_nfa[m_root].AddLambdaEdge(target);
}
for (int i = 0; i < m_nfa.Count; ++i)
{
var reachable = new HashSet <int> {
i
};
ClosureNFA(reachable);
m_nfa[i].NFAClosure = reachable;
}
var nfaList = new HashSet <int> {
m_root
};
result.DfaStartState = BuildDFAState(nfaList);
foreach (var build in m_dfa)
{
Debug.Assert(build.TableIndex == result.DFA.Count);
var state = new DFAState
{
TableIndex = build.TableIndex
};
// copy edges.
foreach (var edge in build.Edges)
{
state.Edges.Add(edge);
//result.AddCharacterSet(edge.Value);
}
// get accept symbol.
if (build.AcceptList.Count == 0)
{
state.Accept = null;
}
else if (build.AcceptList.Count == 1)
{
state.Accept = build.AcceptList[0].Symbol;
}
else
{
var accept = build.AcceptList[0];
var priority = accept.Priority;
var list = new List <Symbol>();
list.Add(accept.Symbol);
for (int i = 1; i < build.AcceptList.Count; ++i)
{
accept = build.AcceptList[i];
if (accept.Priority == priority)
{
list.Add(accept.Symbol);
}
else if (accept.Priority < priority)
{
list.Clear();
list.Add(accept.Symbol);
priority = accept.Priority;
}
}
build.AcceptList.Clear();
foreach (var symbol in list)
{
build.AddAccept(symbol, priority);
}
if (list.Count == 1)
{
state.Accept = list[0];
}
}
result.DFA.Add(state);
}
CheckErrorsDFA(result);
Console.WriteLine("DFA States Completed");
}
internal GrammarTables ReadGrammarTables()
{
ushort symbolsSize = ReadUInt16();
ushort charSetsSize = ReadUInt16();
ushort productionsSize = ReadUInt16();
ushort faStatesSize = ReadUInt16();
ushort lrActionsListsSize = ReadUInt16();
ushort groupsSize = ReadUInt16();
//Keep it for later use in addition to reading it
grammarTables = new GrammarTables(symbolsSize, charSetsSize, productionsSize,
faStatesSize, lrActionsListsSize, groupsSize);
return grammarTables;
}
