/// <summary>
/// Gets all nonterminals defined by the <see cref="Grammar" />.
/// </summary>
/// <returns>An array of <see cref="NonterminalType" /> that represents all nonterminals defined by the <see cref="Grammar" />.</returns>
public NonterminalType[] GetNonterminals()
{
var nonterminals = new NonterminalType[_nonterminals.Values.Count];
_nonterminals.Values.CopyTo(nonterminals, 0);
return(nonterminals);
}
/// <summary>
/// Gets the <see cref="ParserState"/> associated with a <see cref="NonterminalType"/> as defined by <see cref="Gotos"/>.
/// </summary>
/// <param name="nonterminalType">A <see cref="NonterminalType"/> object.</param>
/// <returns>The <see cref="ParserState"/> associated with <paramref name="nonterminalType"/> as defined by <see cref="Gotos"/>.
/// Returns <value>null</value> if no such <see cref="ParserState"/> exists.</returns>
public ParserState GetGoto(NonterminalType nonterminalType)
{
ParserState state;
if (m_gotos.TryGetValue(nonterminalType, out state))
{
return(state);
}
return(null);
}
/// <summary>
/// Retrieves the terminal or nonterminal definition from the specified <see cref="Type"/> and adds it to the
/// <see cref="Grammar"/>.
/// </summary>
/// <param name="type">A <see cref="Type"/> containing a terminal or nonterminal definition.</param>
/// <param name="name">The name of the grammar being loaded as defined by <see cref="GrammarAttribute"/>. Specify <value>null</value> to load <paramref name="type"/> regardless of grammar name.</param>
/// <returns>The <see cref="LanguageElementType"/> added to the <see cref="Grammar"/>. If the specified <see cref="Type"/>
/// did not represent a terminal or nonterminal definition, <value>null</value> is returned.
/// </returns>
public LanguageElementType Load(Type type, string name)
{
if (TypeIsTerminal(type, name))
{
TerminalType terminalType = new TerminalType(type);
m_terminals.Add(type, terminalType);
return(terminalType);
}
if (TypeIsNonterminal(type, name))
{
NonterminalType nonterminalType = new NonterminalType(type);
m_nonterminals.Add(type, nonterminalType);
return(nonterminalType);
}
return(null);
}
private void ComputeClosure(IGrammar grammar, HashSet <GeneratorStateItem> items)
{
// Continue to loop until new more elements are added to the state.
//
bool stateModified = true;
while (stateModified)
{
HashSet <GeneratorStateItem> newItems = new HashSet <GeneratorStateItem>();
// Iterate over the current elements in the state and determine (possible) new
// elements to be added.
//
foreach (GeneratorStateItem item in items)
{
LanguageElementType languageElement = item.RuleItem.DotElement;
if (languageElement != null &&
languageElement.ElementType == LanguageElementTypes.Nonterminal)
{
NonterminalType nonterminal = (NonterminalType)languageElement;
foreach (RuleType rule in nonterminal.Rules)
{
GeneratorStateItem newItem = new GeneratorStateItem(new GeneratorRuleItem(rule, 0));
newItems.Add(newItem);
}
}
}
// Exit loop if all potential new elements already exist in state. Otherwise, add new elements
// and repeat process.
//
if (newItems.IsSubsetOf(items))
{
stateModified = false;
}
else
{
items.UnionWith(newItems);
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="RuleType"/> class.
/// </summary>
/// <param name="methodInfo">The <see cref="MethodInfo"/> associated with this <see cref="RuleType"/>.</param>
/// <param name="priority">The priority of this rule used to resolve conflicts with other rules during parser generation.</param>
/// <param name="lhs">The <see cref="NonterminalType"/> representing the LHS of this rule.</param>
/// <param name="rhs">The collection of <see cref="LanguageElementType"/> representing the RHS of this rule.</param>
public RuleType(MethodInfo methodInfo, int priority, NonterminalType lhs, LanguageElementType[] rhs)
{
var sb = new StringBuilder();
sb.Append(methodInfo.Name);
sb.Append("[");
string prefix = null;
foreach (var parameter in methodInfo.GetParameters())
{
sb.Append(prefix); prefix = ",";
sb.Append(parameter.ParameterType.Name);
}
sb.Append("]");
var name = sb.ToString();
FullName = string.Format("{0}::{1}", methodInfo.DeclaringType.FullName, name);
Name = name;
_delegate = parameters => methodInfo.Invoke(null, parameters);
Priority = priority;
_lhs = lhs;
Rhs = rhs;
}
/// <summary>
/// Initializes a new instance of the <see cref="RuleType"/> class.
/// </summary>
/// <param name="methodInfo">The <see cref="MethodInfo"/> associated with this <see cref="RuleType"/>.</param>
/// <param name="priority">The priority of this rule used to resolve conflicts with other rules during parser generation.</param>
/// <param name="lhs">The <see cref="NonterminalType"/> representing the LHS of this rule.</param>
/// <param name="rhs">The collection of <see cref="LanguageElementType"/> representing the RHS of this rule.</param>
public RuleType(MethodInfo methodInfo, int priority, NonterminalType lhs, LanguageElementType[] rhs)
{
StringBuilder sb = new StringBuilder();
sb.Append(methodInfo.Name);
sb.Append("[");
string prefix = null;
foreach (ParameterInfo parameter in methodInfo.GetParameters())
{
sb.Append(prefix); prefix = ",";
sb.Append(parameter.ParameterType.Name);
}
sb.Append("]");
string name = sb.ToString();
m_fullName = string.Format("{0}::{1}", methodInfo.DeclaringType.FullName, name);
m_name = name;
m_delegate = delegate(LanguageElement[] parameters) { methodInfo.Invoke(null, parameters); };
m_priority = priority;
m_lhs = lhs;
m_rhs = rhs;
}
/// <summary>
/// Retrieves all rule definitions from the specified <see cref="Type"/> and adds them to the <see cref="Grammar"/>.
/// </summary>
/// <param name="type">A <see cref="Type"/> containing rule definitions.</param>
/// <param name="name">The name of the grammar being loaded as defined by <see cref="GrammarAttribute"/>. Specify <value>null</value> to load <paramref name="type"/> regardless of grammar name.</param>
public void LoadRules(Type type, string name)
{
// Ensure type is in specified grammar.
//
if (!IsGrammarType(type, name))
{
return;
}
// Load rules defined by type.
//
foreach (MethodInfo method in type.GetMethods())
{
ParameterInfo[] parameters = method.GetParameters();
if (MethodIsRule(method, parameters))
{
// Determine priority associated with rule.
//
int priority = 0;
object[] attributes = method.GetCustomAttributes(typeof(RuleAttribute), false);
if (attributes.Length > 0)
{
RuleAttribute attribute = attributes[0] as RuleAttribute;
if (attribute != null)
{
priority = attribute.Priority;
}
}
// Find the grammer language elements associated with each parameter member.
//
NonterminalType lhs = null;
List <LanguageElementType> rhs = new List <LanguageElementType>();
for (int idx = 0; idx < parameters.Length; ++idx)
{
Type parameterType = parameters[idx].ParameterType;
if (idx == 0)
{
NonterminalType nonterminal;
if (m_nonterminals.TryGetValue(parameterType, out nonterminal))
{
lhs = nonterminal;
}
else
{
throw new InvalidOperationException();
}
}
else
{
NonterminalType nonterminal;
if (m_nonterminals.TryGetValue(parameterType, out nonterminal))
{
rhs.Add(nonterminal);
}
else
{
TerminalType terminal;
if (m_terminals.TryGetValue(parameterType, out terminal))
{
rhs.Add(terminal);
}
else
{
// If parameterType is currently not defined by the grammar, attempt to process it
// now. This occurs when OptionalTerminal<> and OptionalNonterminal<> types
// appear in the RHS side of a rule.
//
LanguageElementType languageElementType = Load(parameterType, name);
if (languageElementType != null)
{
rhs.Add(languageElementType);
LoadRules(parameterType, name);
}
else
{
throw new InvalidOperationException("Unrecognized rule argument.");
}
}
}
}
}
// Create the rule.
//
RuleType rule = new RuleType(method, priority, lhs, rhs.ToArray());
lhs.Rules.Add(rule);
}
}
}
private void ComputeFollow()
{
StartNonterminal.Follow.Add(StopTerminal);
// Continue adding elements until no more changes to FOLLOW are made.
//
bool change = true;
while (change)
{
change = false;
// Iterate over all nonterminals and their rules.
//
foreach (NonterminalType x in m_nonterminals.Values)
{
foreach (RuleType rule in x.Rules)
{
// For rules of the form X -> ... Y B1 B2 ... Bn, add FIRST(Bi) (excluding e)
// to FOLLOW(Y) if FIRST(Bj) contains e for all j < i. Add FOLLOW(X) to
// FOLLOW(Y) if FIRST(Bi) contains e for all i.
//
for (int idx = 0; idx < rule.Rhs.Length; ++idx)
{
if (rule.Rhs[idx].ElementType == LanguageElementTypes.Nonterminal)
{
NonterminalType y = (NonterminalType)rule.Rhs[idx];
bool epsilonInAllB = true;
for (int j = idx + 1; j < rule.Rhs.Length; ++j)
{
LanguageElementType b = rule.Rhs[j];
HashSet <TerminalType> bFirst = b.First.GetSetExcludingEpsilon();
if (bFirst.Count > 0 &&
!bFirst.IsSubsetOf(y.Follow))
{
y.Follow.UnionWith(bFirst);
change = true;
}
if (!b.First.ContainsEpsilon)
{
epsilonInAllB = false;
break;
}
}
if (epsilonInAllB)
{
if (x.Follow.Count > 0 &&
!x.Follow.IsSubsetOf(y.Follow))
{
y.Follow.UnionWith(x.Follow);
change = true;
}
}
}
}
}
}
}
}
/// <summary>
/// Constructs a new <see cref="Parser"/> which can recoganize the specified <see cref="IGrammar"/>.
/// </summary>
/// <param name="grammar">The <see cref="IGrammar"/> to be recognized by the <see cref="Parser"/>.</param>
/// <returns>A <see cref="ParserGeneratorResult"/> containing <see cref="Parser"/> and information pertaining to the
/// success or failure of the generation process.
/// </returns>
public ParserGeneratorResult GenerateParser(IGrammar grammar)
{
List <ParserGeneratorParserConflict> conflicts = new List <ParserGeneratorParserConflict>();
List <GeneratorState> states = CreateStates(grammar);
// Create a parser state for each generator state.
//
Dictionary <GeneratorState, ParserState> parserStates = new Dictionary <GeneratorState, ParserState>();
foreach (GeneratorState state in states)
{
parserStates.Add(state, new ParserState(state.Id));
}
foreach (GeneratorState state in states)
{
LinguaTrace.TraceEvent(TraceEventType.Verbose, LinguaTraceId.ID_GENERATE_PROCESS_STATE, "{0}", state);
List <GeneratorStateItem> items = new List <GeneratorStateItem>(state.Items);
items.Sort();
// Construct the list of actions associated with the parser state.
//
Dictionary <TerminalType, ParserAction> actions = new Dictionary <TerminalType, ParserAction>();
Dictionary <ParserAction, GeneratorRuleItem> actionRules = new Dictionary <ParserAction, GeneratorRuleItem>();
foreach (GeneratorStateItem item in items)
{
LinguaTrace.TraceEvent(TraceEventType.Verbose, LinguaTraceId.ID_GENERATE_PROCESS_ITEM, "{0}", item);
if (item.RuleItem.DotElement == null)
{
foreach (TerminalType terminal in item.RuleItem.Rule.Lhs.Follow)
{
LinguaTrace.TraceEvent(TraceEventType.Verbose, LinguaTraceId.ID_GENERATE_PROCESS_TERMINAL, "{0}", terminal);
if (actions.ContainsKey(terminal))
{
ParserGeneratorParserConflict conflict = new ParserGeneratorParserConflict(
actionRules[actions[terminal]].ToString(),
item.RuleItem.ToString());
LinguaTrace.TraceEvent(TraceEventType.Information, LinguaTraceId.ID_GENERATE_PROCESS_CONFLICT, "{0}", conflict);
conflicts.Add(conflict);
}
else if (item.RuleItem.Rule.Lhs.IsStart &&
terminal.IsStop)
{
ParserAction action = new ParserActionAccept(item.RuleItem.Rule);
LinguaTrace.TraceEvent(TraceEventType.Information, LinguaTraceId.ID_GENERATE_PROCESS_ACTION, "{0}", action);
actions.Add(terminal, action);
actionRules.Add(action, item.RuleItem);
}
else
{
ParserAction action = new ParserActionReduce(item.RuleItem.Rule);
LinguaTrace.TraceEvent(TraceEventType.Information, LinguaTraceId.ID_GENERATE_PROCESS_ACTION, "{0}", action);
actions.Add(terminal, action);
actionRules.Add(action, item.RuleItem);
}
}
}
else if (item.RuleItem.DotElement.ElementType == LanguageElementTypes.Terminal)
{
TerminalType terminal = (TerminalType)item.RuleItem.DotElement;
if (actions.ContainsKey(terminal))
{
ParserGeneratorParserConflict conflict = new ParserGeneratorParserConflict(
actionRules[actions[terminal]].ToString(),
item.RuleItem.ToString());
LinguaTrace.TraceEvent(TraceEventType.Information, LinguaTraceId.ID_GENERATE_PROCESS_CONFLICT, "{0}", conflict);
conflicts.Add(conflict);
}
else
{
ParserAction action = new ParserActionShift(parserStates[state.Transitions[terminal]]);
LinguaTrace.TraceEvent(TraceEventType.Information, LinguaTraceId.ID_GENERATE_PROCESS_ACTION, "{0}", action);
actions.Add(terminal, action);
actionRules.Add(action, item.RuleItem);
}
}
}
// Construct the GOTO table
//
Dictionary <NonterminalType, ParserState> gotos = new Dictionary <NonterminalType, ParserState>();
foreach (KeyValuePair <LanguageElementType, GeneratorState> transition in state.Transitions)
{
if (transition.Key.ElementType == LanguageElementTypes.Nonterminal)
{
NonterminalType nonterminal = (NonterminalType)transition.Key;
gotos.Add(nonterminal, parserStates[transition.Value]);
}
}
// Update the parser state.
//
ParserState parserState = parserStates[state];
foreach (KeyValuePair <TerminalType, ParserAction> action in actions)
{
parserState.Actions.Add(action.Key, action.Value);
}
foreach (KeyValuePair <NonterminalType, ParserState> gotoItem in gotos)
{
parserState.Gotos.Add(gotoItem.Key, gotoItem.Value);
}
}
Parser parser = new Parser(parserStates[states[0]]);
ParserGeneratorResult result = new ParserGeneratorResult(parser, conflicts);
return(result);
}
/// <summary>
/// Gets the <see cref="ParserState"/> associated with a <see cref="NonterminalType"/> as defined by <see cref="Gotos"/>.
/// </summary>
/// <param name="nonterminalType">A <see cref="NonterminalType"/> object.</param>
/// <returns>The <see cref="ParserState"/> associated with <paramref name="nonterminalType"/> as defined by <see cref="Gotos"/>.
/// Returns <value>null</value> if no such <see cref="ParserState"/> exists.</returns>
public ParserState GetGoto(NonterminalType nonterminalType)
{
ParserState state;
return _gotos.TryGetValue(nonterminalType, out state) ? state : null;
}
/// <summary>
/// Gets all nonterminals defined by the <see cref="Grammar" />.
/// </summary>
/// <returns>An array of <see cref="NonterminalType" /> that represents all nonterminals defined by the <see cref="Grammar" />.</returns>
public NonterminalType[] GetNonterminals()
{
NonterminalType[] nonterminals = new NonterminalType[m_nonterminals.Values.Count];
m_nonterminals.Values.CopyTo(nonterminals, 0);
return nonterminals;
}
/// <summary>
/// Retrieves the terminal or nonterminal definition from the specified <see cref="Type"/> and adds it to the
/// <see cref="Grammar"/>.
/// </summary>
/// <param name="type">A <see cref="Type"/> containing a terminal or nonterminal definition.</param>
/// <param name="name">The name of the grammar being loaded as defined by <see cref="GrammarAttribute"/>. Specify <value>null</value> to load <paramref name="type"/> regardless of grammar name.</param>
/// <returns>The <see cref="LanguageElementType"/> added to the <see cref="Grammar"/>. If the specified <see cref="Type"/>
/// did not represent a terminal or nonterminal definition, <value>null</value> is returned.
/// </returns>
public LanguageElementType Load(Type type, string name)
{
if (TypeIsTerminal(type, name))
{
TerminalType terminalType = new TerminalType(type);
m_terminals.Add(type, terminalType);
return terminalType;
}
if (TypeIsNonterminal(type, name))
{
NonterminalType nonterminalType = new NonterminalType(type);
m_nonterminals.Add(type, nonterminalType);
return nonterminalType;
}
return null;
}
/// <summary>
/// Gets the <see cref="ParserState"/> associated with a <see cref="NonterminalType"/> as defined by <see cref="Gotos"/>.
/// </summary>
/// <param name="nonterminalType">A <see cref="NonterminalType"/> object.</param>
/// <returns>The <see cref="ParserState"/> associated with <paramref name="nonterminalType"/> as defined by <see cref="Gotos"/>.
/// Returns <value>null</value> if no such <see cref="ParserState"/> exists.</returns>
public ParserState GetGoto(NonterminalType nonterminalType)
{
ParserState state;
if (m_gotos.TryGetValue(nonterminalType, out state))
{
return state;
}
return null;
}
/// <summary>
/// Gets the <see cref="ParserState"/> associated with a <see cref="NonterminalType"/> as defined by <see cref="Gotos"/>.
/// </summary>
/// <param name="nonterminalType">A <see cref="NonterminalType"/> object.</param>
/// <returns>The <see cref="ParserState"/> associated with <paramref name="nonterminalType"/> as defined by <see cref="Gotos"/>.
/// Returns <value>null</value> if no such <see cref="ParserState"/> exists.</returns>
public ParserState GetGoto(NonterminalType nonterminalType)
{
ParserState state;
return _gotos.TryGetValue(nonterminalType, out state) ? state : null;
}