protected virtual void OptimizeExitBranches(DFAState d)
{
int sI = d.stateNumber;
if (_visited.Contains(sI))
{
return; // already visited
}
_visited.Add(sI);
int nAlts = d.dfa.NumberOfAlts;
for (int i = 0; i < d.NumberOfTransitions; i++)
{
Transition edge = (Transition)d.Transition(i);
DFAState edgeTarget = ((DFAState)edge.target);
/*
* [email protected](d.stateNumber+"-"+
* edge.label.toString(d.dfa.nfa.grammar)+"->"+
* edgeTarget.stateNumber);
*/
// if target is an accept state and that alt is the exit alt
if (edgeTarget.IsAcceptState &&
edgeTarget.GetUniquelyPredictedAlt() == nAlts)
{
/*
* [email protected]("ignoring transition "+i+" to max alt "+
* d.dfa.getNumberOfAlts());
*/
d.RemoveTransition(i);
i--; // back up one so that i++ of loop iteration stays within bounds
}
OptimizeExitBranches(edgeTarget);
}
}
public List <DFAState> GetAnyDFAPathToTarget(DFAState startState, DFAState targetState, HashSet <DFAState> visited)
{
List <DFAState> dfaStates = new List <DFAState>();
visited.Add(startState);
if (startState.Equals(targetState))
{
dfaStates.Add(targetState);
return(dfaStates);
}
// for (Edge e : startState.edges) { // walk edges looking for valid
// path
for (int i = 0; i < startState.NumberOfTransitions; i++)
{
Transition e = startState.GetTransition(i);
if (!visited.Contains((DFAState)e.Target))
{
List <DFAState> path = GetAnyDFAPathToTarget((DFAState)e.target, targetState, visited);
if (path != null)
{ // found path, we're done
dfaStates.Add(startState);
dfaStates.AddRange(path);
return(dfaStates);
}
}
}
return(null);
}
/** Report the list of predicates found for each alternative; copy
* the list because this set gets altered later by the method
* tryToResolveWithSemanticPredicates() while flagging NFA configurations
* in d as resolved.
*/
public virtual void ReportAltPredicateContext(DFAState d, IDictionary <int, SemanticContext> altPredicateContext)
{
IDictionary <int, SemanticContext> copy = new Dictionary <int, SemanticContext>(altPredicateContext);
//copy.putAll( altPredicateContext );
_stateToAltSetWithSemanticPredicatesMap[d] = copy;
}
/** Two DFAStates are equal if their NFA configuration sets are the
* same. This method is used to see if a DFA state already exists.
*
* Because the number of alternatives and number of NFA configurations are
* finite, there is a finite number of DFA states that can be processed.
* This is necessary to show that the algorithm terminates.
*
* Cannot test the DFA state numbers here because in DFA.addState we need
* to know if any other state exists that has this exact set of NFA
* configurations. The DFAState state number is irrelevant.
*/
public override bool Equals(object o)
{
// compare set of NFA configurations in this set with other
DFAState other = o as DFAState;
if (other == null)
{
return(false);
}
if (object.ReferenceEquals(_nfaConfigurations, other._nfaConfigurations))
{
return(true);
}
if (this._nfaConfigurations.Equals(other._nfaConfigurations))
{
return(true);
}
if (_nfaConfigurations.SequenceEqual(other._nfaConfigurations))
{
return(true);
}
return(false);
}
/** Given a start state and a final state, find a list of edge labels
* between the two ignoring epsilon. Limit your scan to a set of states
* passed in. This is used to show a sample input sequence that is
* nondeterministic with respect to this decision. Return IList<Label> as
* a parameter. The incoming states set must be all states that lead
* from startState to targetState and no others so this algorithm doesn't
* take a path that eventually leads to a state other than targetState.
* Don't follow loops, leading to short (possibly shortest) path.
*/
protected virtual void GetSampleInputSequenceUsingStateSet(State startState,
State targetState,
HashSet <object> states,
IList <Label> labels)
{
_statesVisitedDuringSampleSequence.Add(startState.StateNumber);
// pick the first edge in states as the one to traverse
for (int i = 0; i < startState.NumberOfTransitions; i++)
{
Transition t = startState.GetTransition(i);
DFAState edgeTarget = (DFAState)t.Target;
if (states.Contains(edgeTarget) &&
!_statesVisitedDuringSampleSequence.Contains(edgeTarget.StateNumber))
{
labels.Add(t.Label); // traverse edge and track label
if (edgeTarget != targetState)
{
// get more labels if not at target
GetSampleInputSequenceUsingStateSet(edgeTarget,
targetState,
states,
labels);
}
// done with this DFA state as we've found a good path to target
return;
}
}
labels.Add(new Label(Label.EPSILON)); // indicate no input found
// this happens on a : {p1}? a | A ;
//ErrorManager.error(ErrorManager.MSG_CANNOT_COMPUTE_SAMPLE_INPUT_SEQ);
}
public List<DFAState> GetAnyDFAPathToTarget(DFAState startState, DFAState targetState, HashSet<DFAState> visited)
{
List<DFAState> dfaStates = new List<DFAState>();
visited.Add(startState);
if (startState.Equals(targetState))
{
dfaStates.Add(targetState);
return dfaStates;
}
// for (Edge e : startState.edges) { // walk edges looking for valid
// path
for (int i = 0; i < startState.NumberOfTransitions; i++)
{
Transition e = startState.GetTransition(i);
if (!visited.Contains((DFAState)e.Target))
{
List<DFAState> path = GetAnyDFAPathToTarget((DFAState)e.Target, targetState, visited);
if (path != null)
{ // found path, we're done
dfaStates.Add(startState);
dfaStates.AddRange(path);
return dfaStates;
}
}
}
return null;
}
public virtual void ReportNondeterminism(DFAState d, HashSet <int> nondeterministicAlts)
{
_altsWithProblem.addAll(nondeterministicAlts); // track overall list
_statesWithSyntacticallyAmbiguousAltsSet.Add(d);
dfa.nfa.grammar.setOfNondeterministicDecisionNumbers.Add(
dfa.DecisionNumber
);
}
public virtual void ReportNondeterminism(DFAState d, HashSet <int> nondeterministicAlts)
{
_altsWithProblem.UnionWith(nondeterministicAlts); // track overall list
_statesWithSyntacticallyAmbiguousAltsSet.Add(d);
_dfa.Nfa.Grammar.setOfNondeterministicDecisionNumbers.Add(
_dfa.NfaStartStateDecisionNumber
);
}
public GrammarInsufficientPredicatesMessage( DecisionProbe probe,
DFAState problemState,
IDictionary<int, ICollection<IToken>> altToLocations )
: base(ErrorManager.MSG_INSUFFICIENT_PREDICATES)
{
this.probe = probe;
this.problemState = problemState;
this.altToLocations = altToLocations;
}
/** Each state in the DFA represents a different input sequence for an
* alt of the decision. Given a DFA state, what is the semantic
* predicate context for a particular alt.
*/
public virtual SemanticContext GetSemanticContextForAlt(DFAState d, int alt)
{
var altToPredMap = _stateToAltSetWithSemanticPredicatesMap.get(d);
if (altToPredMap == null)
{
return(null);
}
return(altToPredMap.get(alt));
}
// S U P P O R T
/** Given a start state and a target state, return true if start can reach
* target state. Also, compute the set of DFA states
* that are on a path from start to target; return in states parameter.
*/
protected virtual bool ReachesState(DFAState startState,
DFAState targetState,
HashSet <object> states)
{
if (startState == targetState)
{
states.Add(targetState);
//[email protected]("found target DFA state "+targetState.getStateNumber());
_stateReachable[startState.stateNumber] = REACHABLE_YES;
return(true);
}
DFAState s = startState;
// avoid infinite loops
_stateReachable[s.stateNumber] = REACHABLE_BUSY;
// look for a path to targetState among transitions for this state
// stop when you find the first one; I'm pretty sure there is
// at most one path to any DFA state with conflicting predictions
for (int i = 0; i < s.NumberOfTransitions; i++)
{
Transition t = s.Transition(i);
DFAState edgeTarget = (DFAState)t.target;
int targetStatus; //= stateReachable.get( edgeTarget.stateNumber );
if (_stateReachable.TryGetValue(edgeTarget.stateNumber, out targetStatus))
{
if (targetStatus == REACHABLE_BUSY)
{ // avoid cycles; they say nothing
continue;
}
if (targetStatus == REACHABLE_YES)
{ // return success!
_stateReachable[s.stateNumber] = REACHABLE_YES;
return(true);
}
if (targetStatus == REACHABLE_NO)
{ // try another transition
continue;
}
}
// if null, target must be REACHABLE_UNKNOWN (i.e., unvisited)
if (ReachesState(edgeTarget, targetState, states))
{
states.Add(s);
_stateReachable[s.stateNumber] = REACHABLE_YES;
return(true);
}
}
_stateReachable[s.stateNumber] = REACHABLE_NO;
return(false); // no path to targetState found.
}
private HashSet <object> GetUnaliasedDFAStateSet(HashSet <object> dfaStatesWithRecursionProblems)
{
HashSet <object> dfaStatesUnaliased = new HashSet <object>();
foreach (int stateI in dfaStatesWithRecursionProblems)
{
DFAState d = dfa.GetState(stateI);
dfaStatesUnaliased.Add(d.stateNumber);
}
return(dfaStatesUnaliased);
}
public RecursionOverflowMessage( DecisionProbe probe,
DFAState sampleBadState,
int alt,
ICollection<string> targetRules,
ICollection<ICollection<NFAState>> callSiteStates )
: base(ErrorManager.MSG_RECURSION_OVERLOW)
{
this.probe = probe;
this.sampleBadState = sampleBadState;
this.alt = alt;
this.targetRules = targetRules;
this.callSiteStates = callSiteStates;
}
protected virtual HashSet <object> GetDFAPathStatesToTarget(DFAState targetState)
{
HashSet <object> dfaStates = new HashSet <object>();
_stateReachable = new Dictionary <int, int>();
if (dfa == null || dfa.startState == null)
{
return(dfaStates);
}
bool reaches = ReachesState(dfa.startState, targetState, dfaStates);
return(dfaStates);
}
public virtual void ReportNondeterminismResolvedWithSemanticPredicate(DFAState d)
{
// First, prevent a recursion warning on this state due to
// pred resolution
if (d.abortedDueToRecursionOverflow)
{
d.dfa.probe.RemoveRecursiveOverflowState(d);
}
_statesResolvedWithSemanticPredicatesSet.Add(d);
//[email protected]("resolved with pred: "+d);
dfa.nfa.grammar.setOfNondeterministicDecisionNumbersResolvedWithPredicates.Add(
dfa.DecisionNumber
);
}
/** Each state in the DFA represents a different input sequence for an
* alt of the decision. Given a DFA state, what is the semantic
* predicate context for a particular alt.
*/
public virtual SemanticContext GetSemanticContextForAlt(DFAState d, int alt)
{
IDictionary <int, SemanticContext> altToPredMap;
_stateToAltSetWithSemanticPredicatesMap.TryGetValue(d, out altToPredMap);
if (altToPredMap == null)
{
return(null);
}
SemanticContext result;
altToPredMap.TryGetValue(alt, out result);
return(result);
}
public virtual void ReportRecursionOverflow(DFAState d,
NFAConfiguration recursionNFAConfiguration)
{
// track the state number rather than the state as d will change
// out from underneath us; hash wouldn't return any value
// left-recursion is detected in start state. Since we can't
// call resolveNondeterminism() on the start state (it would
// not look k=1 to get min single token lookahead), we must
// prevent errors derived from this state. Avoid start state
if (d.stateNumber > 0)
{
int stateI = d.stateNumber;
_stateToRecursionOverflowConfigurationsMap.Map(stateI, recursionNFAConfiguration);
}
}
/** Walk DFA states, unlinking the nfa configs and whatever else I
* can to reduce memory footprint.
*/
protected virtual void UnlinkUnneededStateData(DFAState d)
{
int sI = d.stateNumber;
if (visited.Contains(sI))
{
return; // already visited
}
visited.Add(sI);
d.nfaConfigurations = null;
for (int i = 0; i < d.NumberOfTransitions; i++)
{
Transition edge = (Transition)d.transition(i);
DFAState edgeTarget = ((DFAState)edge.target);
UnlinkUnneededStateData(edgeTarget);
}
}
/** Return a IList<Label> indicating an input sequence that can be matched
* from the start state of the DFA to the targetState (which is known
* to have a problem).
*/
public virtual IList <Label> GetSampleNonDeterministicInputSequence(DFAState targetState)
{
HashSet <object> dfaStates = GetDFAPathStatesToTarget(targetState);
_statesVisitedDuringSampleSequence = new HashSet <int>();
IList <Label> labels = new List <Label>(); // may access ith element; use array
if (dfa == null || dfa.startState == null)
{
return(labels);
}
GetSampleInputSequenceUsingStateSet(dfa.startState,
targetState,
dfaStates,
labels);
return(labels);
}
/** From list of lookahead sets (one per alt in decision), create
* an LL(1) DFA. One edge per set.
*
* s0-{alt1}->:o=>1
* | \
* | -{alt2}->:o=>2
* |
* ...
*/
public LL1DFA(int decisionNumber, NFAState decisionStartState, LookaheadSet[] altLook)
: base(decisionNumber, decisionStartState)
{
DFAState s0 = NewState();
StartState = s0;
UnreachableAlts.Clear();
for (int alt = 1; alt < altLook.Length; alt++)
{
DFAState acceptAltState = NewState();
acceptAltState.IsAcceptState = true;
SetAcceptState(alt, acceptAltState);
acceptAltState.LookaheadDepth = 1;
acceptAltState.CachedUniquelyPredicatedAlt = alt;
Label e = GetLabelForSet(altLook[alt].TokenTypeSet);
s0.AddTransition(acceptAltState, e);
}
}
private void ComputeAltToProblemMaps(IEnumerable <int> dfaStatesUnaliased,
IDictionary <int, IList <NFAConfiguration> > configurationsMap,
IDictionary <int, IDictionary <string, ICollection <NFAState> > > altToTargetToCallSitesMap,
IDictionary <int, DFAState> altToDFAState)
{
foreach (int stateI in dfaStatesUnaliased)
{
// walk this DFA's config list
IList <NFAConfiguration> configs;
configurationsMap.TryGetValue(stateI, out configs);
for (int i = 0; i < configs.Count; i++)
{
NFAConfiguration c = (NFAConfiguration)configs[i];
NFAState ruleInvocationState = _dfa.Nfa.GetState(c.State);
Transition transition0 = ruleInvocationState.transition[0];
RuleClosureTransition @ref = (RuleClosureTransition)transition0;
string targetRule = ((NFAState)@ref.Target).enclosingRule.Name;
int altI = c.Alt;
IDictionary <string, ICollection <NFAState> > targetToCallSiteMap;
altToTargetToCallSitesMap.TryGetValue(altI, out targetToCallSiteMap);
if (targetToCallSiteMap == null)
{
targetToCallSiteMap = new Dictionary <string, ICollection <NFAState> >();
altToTargetToCallSitesMap[altI] = targetToCallSiteMap;
}
ICollection <NFAState> callSites;
targetToCallSiteMap.TryGetValue(targetRule, out callSites);
if (callSites == null)
{
callSites = new HashSet <NFAState>();
targetToCallSiteMap[targetRule] = callSites;
}
callSites.Add(ruleInvocationState);
// track one problem DFA state per alt
DFAState state;
if (!altToDFAState.TryGetValue(altI, out state) || state == null)
{
DFAState sampleBadState = _dfa.GetState(stateI);
altToDFAState[altI] = sampleBadState;
}
}
}
}
protected virtual void OptimizeEOTBranches(DFAState state)
{
if (state == null)
{
throw new ArgumentNullException("state");
}
int sI = state.StateNumber;
if (_visited.Contains(sI))
{
return; // already visited
}
_visited.Add(sI);
for (int i = 0; i < state.NumberOfTransitions; i++)
{
Transition edge = state.GetTransition(i);
DFAState edgeTarget = ((DFAState)edge.Target);
/*
* [email protected](d.stateNumber+"-"+
* edge.label.toString(d.dfa.nfa.grammar)+"->"+
* edgeTarget.stateNumber);
*/
// if only one edge coming out, it is EOT, and target is accept prune
if (PRUNE_TOKENS_RULE_SUPERFLUOUS_EOT_EDGES &&
edgeTarget.IsAcceptState &&
state.NumberOfTransitions == 1 &&
edge.Label.IsAtom &&
edge.Label.Atom == Label.EOT)
{
//[email protected]("state "+d+" can be pruned");
// remove the superfluous EOT edge
state.RemoveTransition(i);
state.IsAcceptState = true; // make it an accept state
// force it to uniquely predict the originally predicted state
state.CachedUniquelyPredicatedAlt = edgeTarget.GetUniquelyPredictedAlt();
i--; // back up one so that i++ of loop iteration stays within bounds
}
OptimizeEOTBranches(edgeTarget);
}
}
/** Return a list of edge labels from start state to targetState. */
public List <IIntSet> GetEdgeLabels(DFAState targetState)
{
List <DFAState> dfaStates = GetAnyDFAPathToTarget(targetState);
List <IIntSet> labels = new List <IIntSet>();
for (int i = 0; i < dfaStates.Count - 1; i++)
{
DFAState d = dfaStates[i];
DFAState nextState = dfaStates[i + 1];
// walk looking for edge whose target is next dfa state
for (int j = 0; j < d.NumberOfTransitions; j++)
{
Transition e = d.GetTransition(j);
if (e.Target.StateNumber == nextState.StateNumber)
{
labels.Add(e.Label.Set);
}
}
}
return(labels);
}
// I N F O R M A T I O N A B O U T D E C I S I O N
/** Return the sorted list of alts that conflict within a single state.
* Note that predicates may resolve the conflict.
*/
public virtual IList <int> GetNonDeterministicAltsForState(DFAState targetState)
{
IEnumerable <int> nondetAlts = targetState.GetNonDeterministicAlts();
if (nondetAlts == null)
{
return(null);
}
return(nondetAlts.OrderBy(i => i).ToList());
//HashSet<int> nondetAlts = targetState.getNonDeterministicAlts();
//if ( nondetAlts == null )
//{
// return null;
//}
//List sorted = new LinkedList();
//sorted.addAll( nondetAlts );
//Collections.sort( sorted ); // make sure it's 1, 2, ...
//return sorted;
}
/** From list of lookahead sets (one per alt in decision), create
* an LL(1) DFA. One edge per set.
*
* s0-{alt1}->:o=>1
* | \
* | -{alt2}->:o=>2
* |
* ...
*/
public LL1DFA(int decisionNumber, NFAState decisionStartState, LookaheadSet[] altLook)
{
DFAState s0 = NewState();
startState = s0;
nfa = decisionStartState.nfa;
NumberOfAlts = nfa.grammar.GetNumberOfAltsForDecisionNFA(decisionStartState);
this.decisionNumber = decisionNumber;
this.NFADecisionStartState = decisionStartState;
InitAltRelatedInfo();
UnreachableAlts = null;
for (int alt = 1; alt < altLook.Length; alt++)
{
DFAState acceptAltState = NewState();
acceptAltState.acceptState = true;
SetAcceptState(alt, acceptAltState);
acceptAltState.LookaheadDepth = 1;
acceptAltState.cachedUniquelyPredicatedAlt = alt;
Label e = GetLabelForSet(altLook[alt].tokenTypeSet);
s0.AddTransition(acceptAltState, e);
}
}
protected virtual void IssueRecursionWarnings()
{
// RECURSION OVERFLOW
ICollection <int> dfaStatesWithRecursionProblems =
_stateToRecursionOverflowConfigurationsMap.Keys;
// now walk truly unique (unaliased) list of dfa states with inf recur
// Goal: create a map from alt to map<target,IList<callsites>>
// Map<Map<String target, IList<NFAState call sites>>
IDictionary <int, IDictionary <string, ICollection <NFAState> > > altToTargetToCallSitesMap =
new Dictionary <int, IDictionary <string, ICollection <NFAState> > >();
// track a single problem DFA state for each alt
var altToDFAState = new Dictionary <int, DFAState>();
ComputeAltToProblemMaps(dfaStatesWithRecursionProblems,
_stateToRecursionOverflowConfigurationsMap,
altToTargetToCallSitesMap, // output param
altToDFAState); // output param
// walk each alt with recursion overflow problems and generate error
ICollection <int> alts = altToTargetToCallSitesMap.Keys;
List <int> sortedAlts = new List <int>(alts);
sortedAlts.Sort();
//Collections.sort( sortedAlts );
foreach (int altI in sortedAlts)
{
var targetToCallSiteMap =
altToTargetToCallSitesMap.get(altI);
var targetRules = targetToCallSiteMap.Keys;
var callSiteStates = targetToCallSiteMap.Values;
DFAState sampleBadState = (DFAState)altToDFAState.get(altI);
ErrorManager.RecursionOverflow(this,
sampleBadState,
altI,
targetRules,
callSiteStates);
}
}
// S U P P O R T
/** Given a start state and a target state, return true if start can reach
* target state. Also, compute the set of DFA states
* that are on a path from start to target; return in states parameter.
*/
protected virtual bool ReachesState( DFAState startState,
DFAState targetState,
HashSet<object> states )
{
if ( startState == targetState )
{
states.Add( targetState );
//[email protected]("found target DFA state "+targetState.getStateNumber());
_stateReachable[startState.StateNumber] = Reachable.Yes;
return true;
}
DFAState s = startState;
// avoid infinite loops
_stateReachable[s.StateNumber] = Reachable.Busy;
// look for a path to targetState among transitions for this state
// stop when you find the first one; I'm pretty sure there is
// at most one path to any DFA state with conflicting predictions
for ( int i = 0; i < s.NumberOfTransitions; i++ )
{
Transition t = s.GetTransition( i );
DFAState edgeTarget = (DFAState)t.Target;
Reachable targetStatus; //= stateReachable.get( edgeTarget.stateNumber );
if ( _stateReachable.TryGetValue( edgeTarget.StateNumber, out targetStatus ) )
{
if ( targetStatus == Reachable.Busy )
{ // avoid cycles; they say nothing
continue;
}
if ( targetStatus == Reachable.Yes )
{ // return success!
_stateReachable[s.StateNumber] = Reachable.Yes;
return true;
}
if ( targetStatus == Reachable.No )
{ // try another transition
continue;
}
}
// if null, target must be REACHABLE_UNKNOWN (i.e., unvisited)
if ( ReachesState( edgeTarget, targetState, states ) )
{
states.Add( s );
_stateReachable[s.StateNumber] = Reachable.Yes;
return true;
}
}
_stateReachable[s.StateNumber] = Reachable.No;
return false; // no path to targetState found.
}
/** From a set of edgeset->list-of-alts mappings, create a DFA
* that uses syn preds for all |list-of-alts|>1.
*/
public LL1DFA(int decisionNumber,
NFAState decisionStartState,
MultiMap <IntervalSet, int> edgeMap)
{
DFAState s0 = NewState();
startState = s0;
nfa = decisionStartState.nfa;
NumberOfAlts = nfa.grammar.GetNumberOfAltsForDecisionNFA(decisionStartState);
this.decisionNumber = decisionNumber;
this.NFADecisionStartState = decisionStartState;
InitAltRelatedInfo();
UnreachableAlts = null;
foreach (var edgeVar in edgeMap)
{
IntervalSet edge = edgeVar.Key;
IList <int> alts = edgeVar.Value;
alts = alts.OrderBy(i => i).ToList();
//Collections.sort( alts ); // make sure alts are attempted in order
//[email protected](edge+" -> "+alts);
DFAState s = NewState();
s.LookaheadDepth = 1;
Label e = GetLabelForSet(edge);
s0.AddTransition(s, e);
if (alts.Count == 1)
{
s.acceptState = true;
int alt = alts[0];
SetAcceptState(alt, s);
s.cachedUniquelyPredicatedAlt = alt;
}
else
{
// resolve with syntactic predicates. Add edges from
// state s that test predicates.
s.IsResolvedWithPredicates = true;
for (int i = 0; i < alts.Count; i++)
{
int alt = (int)alts[i];
s.cachedUniquelyPredicatedAlt = NFA.INVALID_ALT_NUMBER;
DFAState predDFATarget = GetAcceptState(alt);
if (predDFATarget == null)
{
predDFATarget = NewState(); // create if not there.
predDFATarget.acceptState = true;
predDFATarget.cachedUniquelyPredicatedAlt = alt;
SetAcceptState(alt, predDFATarget);
}
// add a transition to pred target from d
/*
* int walkAlt =
* decisionStartState.translateDisplayAltToWalkAlt(alt);
* NFAState altLeftEdge = nfa.grammar.getNFAStateForAltOfDecision(decisionStartState, walkAlt);
* NFAState altStartState = (NFAState)altLeftEdge.transition[0].target;
* SemanticContext ctx = nfa.grammar.ll1Analyzer.getPredicates(altStartState);
* [email protected]("sem ctx = "+ctx);
* if ( ctx == null ) {
* ctx = new SemanticContext.TruePredicate();
* }
* s.addTransition(predDFATarget, new Label(ctx));
*/
SemanticContext.Predicate synpred =
GetSynPredForAlt(decisionStartState, alt);
if (synpred == null)
{
synpred = new SemanticContext.TruePredicate();
}
s.AddTransition(predDFATarget, new PredicateLabel(synpred));
}
}
}
//[email protected]("dfa for preds=\n"+this);
}
public void RemoveState( DFAState d )
{
DFAState it;
if ( _uniqueStates.TryGetValue( d, out it ) )
{
_uniqueStates.Remove( d );
if ( it != null )
{
_numberOfStates--;
}
}
}
private int CalculateMaxLookaheadDepth(DFAState d, int depth)
{
// not cyclic; don't worry about termination
// fail if pred edge.
int max = depth;
for (int i = 0; i < d.NumberOfTransitions; i++)
{
Transition t = d.GetTransition(i);
// if ( t.isSemanticPredicate() ) return Integer.MAX_VALUE;
if (!t.IsSemanticPredicate)
{
// if pure pred not gated, it must target stop state; don't count
DFAState edgeTarget = (DFAState)t.Target;
int m = CalculateMaxLookaheadDepth(edgeTarget, depth + 1);
max = Math.Max(max, m);
}
}
return max;
}
protected virtual void CreateTransitionTableEntryForState( DFAState s )
{
/*
[email protected]("createTransitionTableEntryForState s"+s.stateNumber+
" dec "+s.dfa.decisionNumber+" cyclic="+s.dfa.isCyclic());
*/
int smax = _max[s.StateNumber];
int smin = _min[s.StateNumber];
int[] stateTransitions = new int[smax - smin + 1];
for ( int i = 0; i < stateTransitions.Length; i++ )
stateTransitions[i] = EmptyValue;
_transition[s.StateNumber] = stateTransitions;
for ( int j = 0; j < s.NumberOfTransitions; j++ )
{
Transition edge = s.GetTransition( j );
Label label = edge.Label;
if ( label.IsAtom && label.Atom >= Label.MIN_CHAR_VALUE )
{
int labelIndex = label.Atom - smin; // offset from 0
stateTransitions[labelIndex] = edge.Target.StateNumber;
}
else if ( label.IsSet )
{
foreach ( var interval in ((IntervalSet)label.Set).Intervals )
{
for ( int i = Math.Max( interval.a, Label.MIN_CHAR_VALUE ); i <= interval.b; i++ )
{
stateTransitions[i - smin] = edge.Target.StateNumber;
}
}
}
}
// track unique state transition tables so we can reuse
int? edgeClass; // = edgeTransitionClassMap.get( stateTransitions );
if ( _edgeTransitionClassMap.TryGetValue( stateTransitions, out edgeClass ) && edgeClass != null )
{
//[email protected]("we've seen this array before; size="+stateTransitions.size());
_transitionEdgeTables[s.StateNumber] = edgeClass;
}
else
{
edgeClass = _edgeTransitionClass;
_transitionEdgeTables[s.StateNumber] = edgeClass;
_edgeTransitionClassMap[stateTransitions] = edgeClass;
_edgeTransitionClass++;
}
}
protected virtual void CreateMinMaxTables( DFAState s )
{
int smin = Label.MAX_CHAR_VALUE + 1;
int smax = Label.MIN_ATOM_VALUE - 1;
for ( int j = 0; j < s.NumberOfTransitions; j++ )
{
Transition edge = (Transition)s.GetTransition( j );
Label label = edge.Label;
if ( label.IsAtom )
{
if ( label.Atom >= Label.MIN_CHAR_VALUE )
{
if ( label.Atom < smin )
{
smin = label.Atom;
}
if ( label.Atom > smax )
{
smax = label.Atom;
}
}
}
else if ( label.IsSet )
{
IntervalSet labels = (IntervalSet)label.Set;
int lmin = labels.GetMinElement();
// if valid char (don't do EOF) and less than current min
if ( lmin < smin && lmin >= Label.MIN_CHAR_VALUE )
{
smin = labels.GetMinElement();
}
if ( labels.GetMaxElement() > smax )
{
smax = labels.GetMaxElement();
}
}
}
if ( smax < 0 )
{
// must be predicates or pure EOT transition; just zero out min, max
smin = Label.MIN_CHAR_VALUE;
smax = Label.MIN_CHAR_VALUE;
}
_min[s.StateNumber] = (char)smin;
_max[s.StateNumber] = (char)smax;
if ( smax < 0 || smin > Label.MAX_CHAR_VALUE || smin < 0 )
{
ErrorManager.InternalError( "messed up: min=" + _min + ", max=" + _max );
}
}
internal List<DFAState> GetAnyDFAPathToTarget(DFAState targetState)
{
HashSet<DFAState> visited = new HashSet<DFAState>();
return GetAnyDFAPathToTarget(_dfa.StartState, targetState, visited);
}
internal virtual bool CalculateHasCycle(DFAState d, IDictionary<DFAState, Cyclic> busy)
{
busy[d] = Cyclic.Busy;
for (int i = 0; i < d.NumberOfTransitions; i++)
{
Transition t = d.GetTransition(i);
DFAState target = (DFAState)t.Target;
Cyclic cond;
if (!busy.TryGetValue(target, out cond))
cond = Cyclic.Unknown;
if (cond == Cyclic.Busy)
return true;
if (cond != Cyclic.Done && CalculateHasCycle(target, busy))
return true;
}
busy[d] = Cyclic.Done;
return false;
}
protected virtual void OptimizeEOTBranches( DFAState d )
{
int sI = d.stateNumber;
if ( _visited.Contains( sI ) )
{
return; // already visited
}
_visited.Add( sI );
for ( int i = 0; i < d.NumberOfTransitions; i++ )
{
Transition edge = (Transition)d.Transition( i );
DFAState edgeTarget = ( (DFAState)edge.target );
/*
[email protected](d.stateNumber+"-"+
edge.label.toString(d.dfa.nfa.grammar)+"->"+
edgeTarget.stateNumber);
*/
// if only one edge coming out, it is EOT, and target is accept prune
if ( PRUNE_TOKENS_RULE_SUPERFLUOUS_EOT_EDGES &&
edgeTarget.IsAcceptState &&
d.NumberOfTransitions == 1 &&
edge.label.IsAtom &&
edge.label.Atom == Label.EOT )
{
//[email protected]("state "+d+" can be pruned");
// remove the superfluous EOT edge
d.RemoveTransition( i );
d.IsAcceptState = true; // make it an accept state
// force it to uniquely predict the originally predicted state
d.cachedUniquelyPredicatedAlt =
edgeTarget.GetUniquelyPredictedAlt();
i--; // back up one so that i++ of loop iteration stays within bounds
}
OptimizeEOTBranches( edgeTarget );
}
}
protected virtual void OptimizeExitBranches( DFAState d )
{
int sI = d.stateNumber;
if ( _visited.Contains( sI ) )
{
return; // already visited
}
_visited.Add( sI );
int nAlts = d.dfa.NumberOfAlts;
for ( int i = 0; i < d.NumberOfTransitions; i++ )
{
Transition edge = (Transition)d.Transition( i );
DFAState edgeTarget = ( (DFAState)edge.target );
/*
[email protected](d.stateNumber+"-"+
edge.label.toString(d.dfa.nfa.grammar)+"->"+
edgeTarget.stateNumber);
*/
// if target is an accept state and that alt is the exit alt
if ( edgeTarget.IsAcceptState &&
edgeTarget.GetUniquelyPredictedAlt() == nAlts )
{
/*
[email protected]("ignoring transition "+i+" to max alt "+
d.dfa.getNumberOfAlts());
*/
d.RemoveTransition( i );
i--; // back up one so that i++ of loop iteration stays within bounds
}
OptimizeExitBranches( edgeTarget );
}
}
/** Walk DFA states, unlinking the nfa configs and whatever else I
* can to reduce memory footprint.
*/
protected virtual void UnlinkUnneededStateData( DFAState d )
{
int sI = d.stateNumber;
if ( visited.Contains( sI ) )
{
return; // already visited
}
visited.Add( sI );
d.nfaConfigurations = null;
for ( int i = 0; i < d.NumberOfTransitions; i++ )
{
Transition edge = (Transition)d.transition( i );
DFAState edgeTarget = ( (DFAState)edge.target );
UnlinkUnneededStateData( edgeTarget );
}
}
/** Return a list of alts whose predicate context was insufficient to
* resolve a nondeterminism for state d.
*/
public virtual IDictionary <int, ICollection <IToken> > GetIncompletelyCoveredAlts(DFAState d)
{
return(_stateToIncompletelyCoveredAltsMap.get(d));
}
internal List <DFAState> GetAnyDFAPathToTarget(DFAState targetState)
{
HashSet <DFAState> visited = new HashSet <DFAState>();
return(GetAnyDFAPathToTarget(_dfa.StartState, targetState, visited));
}
internal virtual bool CalculateHasSynPred(DFAState d, HashSet<DFAState> busy)
{
busy.Add(d);
for (int i = 0; i < d.NumberOfTransitions; i++)
{
Transition t = d.GetTransition(i);
if (t.IsSemanticPredicate)
{
SemanticContext ctx = t.Label.SemanticContext;
// if ( ctx.toString().indexOf("synpred")>=0 ) {
// System.out.println("has pred "+ctx.toString()+" "+ctx.isSyntacticPredicate());
// System.out.println(((SemanticContext.Predicate)ctx).predicateAST.token);
// }
if (ctx.IsSyntacticPredicate)
return true;
}
DFAState edgeTarget = (DFAState)t.Target;
if (!busy.Contains(edgeTarget) &&CalculateHasSynPred(edgeTarget, busy))
return true;
}
return false;
}
/** A special state is huge (too big for state tables) or has a predicated
* edge. Generate a simple if-then-else. Cannot be an accept state as
* they have no emanating edges. Don't worry about switch vs if-then-else
* because if you get here, the state is super complicated and needs an
* if-then-else. This is used by the new DFA scheme created June 2006.
*/
public virtual StringTemplate GenerateSpecialState( DFAState s )
{
StringTemplate stateST;
stateST = templates.GetInstanceOf( "cyclicDFAState" );
stateST.SetAttribute( "needErrorClause", true );
stateST.SetAttribute( "semPredState", s.IsResolvedWithPredicates );
stateST.SetAttribute( "stateNumber", s.stateNumber );
stateST.SetAttribute( "decisionNumber", s.dfa.decisionNumber );
bool foundGatedPred = false;
StringTemplate eotST = null;
for ( int i = 0; i < s.NumberOfTransitions; i++ )
{
Transition edge = (Transition)s.Transition( i );
StringTemplate edgeST;
if ( edge.label.Atom == Label.EOT )
{
// this is the default clause; has to held until last
edgeST = templates.GetInstanceOf( "eotDFAEdge" );
stateST.RemoveAttribute( "needErrorClause" );
eotST = edgeST;
}
else
{
edgeST = templates.GetInstanceOf( "cyclicDFAEdge" );
StringTemplate exprST =
GenLabelExpr( templates, edge, 1 );
edgeST.SetAttribute( "labelExpr", exprST );
}
edgeST.SetAttribute( "edgeNumber", i + 1 );
edgeST.SetAttribute( "targetStateNumber",
edge.target.stateNumber );
// stick in any gated predicates for any edge if not already a pred
if ( !edge.label.IsSemanticPredicate )
{
DFAState t = (DFAState)edge.target;
SemanticContext preds = t.GetGatedPredicatesInNFAConfigurations();
if ( preds != null )
{
foundGatedPred = true;
StringTemplate predST = preds.GenExpr( this,
Templates,
t.dfa );
edgeST.SetAttribute( "predicates", predST.ToString() );
}
}
if ( edge.label.Atom != Label.EOT )
{
stateST.SetAttribute( "edges", edgeST );
}
}
if ( foundGatedPred )
{
// state has >= 1 edge with a gated pred (syn or sem)
// must rewind input first, set flag.
stateST.SetAttribute( "semPredState", foundGatedPred );
}
if ( eotST != null )
{
stateST.SetAttribute( "edges", eotST );
}
return stateST;
}
/** Return a list of edge labels from start state to targetState. */
public List<IIntSet> GetEdgeLabels(DFAState targetState)
{
List<DFAState> dfaStates = GetAnyDFAPathToTarget(targetState);
List<IIntSet> labels = new List<IIntSet>();
for (int i = 0; i < dfaStates.Count - 1; i++)
{
DFAState d = dfaStates[i];
DFAState nextState = dfaStates[i + 1];
// walk looking for edge whose target is next dfa state
for (int j = 0; j < d.NumberOfTransitions; j++)
{
Transition e = d.GetTransition(j);
if (e.Target.StateNumber == nextState.StateNumber)
{
labels.Add(e.Label.Set);
}
}
}
return labels;
}
internal virtual bool CalculateHasSemPred(DFAState d, HashSet<DFAState> busy)
{
busy.Add(d);
for (int i = 0; i < d.NumberOfTransitions; i++)
{
Transition t = d.GetTransition(i);
if (t.IsSemanticPredicate)
{
SemanticContext ctx = t.Label.SemanticContext;
if (ctx.HasUserSemanticPredicate)
return true;
}
DFAState edgeTarget = (DFAState)t.Target;
if (!busy.Contains(edgeTarget) && CalculateHasSemPred(edgeTarget, busy))
return true;
}
return false;
}
/** Currently the analysis reports issues between token definitions, but
* we don't print out warnings in favor of just picking the first token
* definition found in the grammar ala lex/flex.
*/
public virtual void ReportLexerRuleNondeterminism(DFAState d, HashSet <int> nondeterministicAlts)
{
stateToSyntacticallyAmbiguousTokensRuleAltsMap[d] = nondeterministicAlts;
}
/** Set up the EOT and EOF tables; we cannot put -1 min/max values so
* we need another way to test that in the DFA transition function.
*/
protected virtual void CreateEOTAndEOFTables( DFAState s )
{
for ( int j = 0; j < s.NumberOfTransitions; j++ )
{
Transition edge = s.GetTransition( j );
Label label = edge.Label;
if ( label.IsAtom )
{
if ( label.Atom == Label.EOT )
{
// eot[s] points to accept state
_eot[s.StateNumber] = edge.Target.StateNumber;
}
else if ( label.Atom == Label.EOF )
{
// eof[s] points to accept state
_eof[s.StateNumber] = edge.Target.StateNumber;
}
}
else if ( label.IsSet )
{
if ( label.Set.Contains( Label.EOT ) )
{
_eot[s.StateNumber] = edge.Target.StateNumber;
}
if ( label.Set.Contains( Label.EOF ) )
{
_eof[s.StateNumber] = edge.Target.StateNumber;
}
}
}
}
/** You can generate a switch rather than if-then-else for a DFA state
* if there are no semantic predicates and the number of edge label
* values is small enough; e.g., don't generate a switch for a state
* containing an edge label such as 20..52330 (the resulting byte codes
* would overflow the method 65k limit probably).
*/
protected internal virtual bool CanGenerateSwitch( DFAState s )
{
if ( !GenerateSwitchesWhenPossible )
{
return false;
}
int size = 0;
for ( int i = 0; i < s.NumberOfTransitions; i++ )
{
Transition edge = (Transition)s.Transition( i );
if ( edge.label.IsSemanticPredicate )
{
return false;
}
// can't do a switch if the edges are going to require predicates
if ( edge.label.Atom == Label.EOT )
{
int EOTPredicts = ( (DFAState)edge.target ).GetUniquelyPredictedAlt();
if ( EOTPredicts == NFA.INVALID_ALT_NUMBER )
{
// EOT target has to be a predicate then; no unique alt
return false;
}
}
// if target is a state with gated preds, we need to use preds on
// this edge then to reach it.
if ( ( (DFAState)edge.target ).GetGatedPredicatesInNFAConfigurations() != null )
{
return false;
}
size += edge.label.Set.Count;
}
if ( s.NumberOfTransitions < MinSwitchAlts ||
size > MaxSwitchCaseLabels )
{
return false;
}
return true;
}
protected virtual void CreateSpecialTable( DFAState s )
{
// number all special states from 0...n-1 instead of their usual numbers
bool hasSemPred = false;
// TODO this code is very similar to canGenerateSwitch. Refactor to share
for ( int j = 0; j < s.NumberOfTransitions; j++ )
{
Transition edge = (Transition)s.GetTransition( j );
Label label = edge.Label;
// can't do a switch if the edges have preds or are going to
// require gated predicates
if ( label.IsSemanticPredicate ||
( (DFAState)edge.Target ).GetGatedPredicatesInNFAConfigurations() != null )
{
hasSemPred = true;
break;
}
}
// if has pred or too big for table, make it special
int smax = _max[s.StateNumber];
int smin = _min[s.StateNumber];
if ( hasSemPred || smax - smin > MAX_STATE_TRANSITIONS_FOR_TABLE )
{
_special[s.StateNumber] = _uniqueCompressedSpecialStateNum;
_uniqueCompressedSpecialStateNum++;
_specialStates.Add( s );
}
else
{
_special[s.StateNumber] = EmptyValue; // not special
}
}
public virtual void ReportIncompletelyCoveredAlts(DFAState d,
IDictionary <int, ICollection <IToken> > altToLocationsReachableWithoutPredicate)
{
_stateToIncompletelyCoveredAltsMap[d] = altToLocationsReachableWithoutPredicate;
}
/** figure out if this state eventually reaches an accept state and
* modify the instance variable 'reduced' to indicate if we find
* at least one state that cannot reach an accept state. This implies
* that the overall DFA is not reduced. This algorithm should be
* linear in the number of DFA states.
*
* The algorithm also tracks which alternatives have no accept state,
* indicating a nondeterminism.
*
* Also computes whether the DFA is cyclic.
*
* TODO: I call getUniquelyPredicatedAlt too much; cache predicted alt
*/
protected virtual bool DoesStateReachAcceptState( DFAState d )
{
if ( d.IsAcceptState )
{
// accept states have no edges emanating from them so we can return
d.AcceptStateReachable = Reachable.Yes;
// this alt is uniquely predicted, remove from nondeterministic list
int predicts = d.GetUniquelyPredictedAlt();
UnreachableAlts.Remove( predicts );
return true;
}
// avoid infinite loops
d.AcceptStateReachable = Reachable.Busy;
bool anEdgeReachesAcceptState = false;
// Visit every transition, track if at least one edge reaches stop state
// Cannot terminate when we know this state reaches stop state since
// all transitions must be traversed to set status of each DFA state.
for ( int i = 0; i < d.NumberOfTransitions; i++ )
{
Transition t = d.GetTransition( i );
DFAState edgeTarget = (DFAState)t.Target;
Reachable targetStatus = edgeTarget.AcceptStateReachable;
if ( targetStatus == Reachable.Busy )
{
// avoid cycles; they say nothing
_cyclic = true;
continue;
}
if ( targetStatus == Reachable.Yes )
{
// avoid unnecessary work
anEdgeReachesAcceptState = true;
continue;
}
if ( targetStatus == Reachable.No )
{
// avoid unnecessary work
continue;
}
// target must be REACHABLE_UNKNOWN (i.e., unvisited)
if ( DoesStateReachAcceptState( edgeTarget ) )
{
anEdgeReachesAcceptState = true;
// have to keep looking so don't break loop
// must cover all states even if we find a path for this state
}
}
if ( anEdgeReachesAcceptState )
{
d.AcceptStateReachable = Reachable.Yes;
}
else
{
d.AcceptStateReachable = Reachable.No;
_reduced = false;
}
return anEdgeReachesAcceptState;
}
protected virtual StringTemplate WalkFixedDFAGeneratingStateMachine(
TemplateGroup templates,
DFA dfa,
DFAState s,
int k )
{
//System.Console.Out.WriteLine( "walk " + s.stateNumber + " in dfa for decision " + dfa.decisionNumber );
if ( s.IsAcceptState )
{
StringTemplate dfaST2 = templates.GetInstanceOf( "dfaAcceptState" );
dfaST2.SetAttribute( "alt", s.GetUniquelyPredictedAlt() );
return dfaST2;
}
// the default templates for generating a state and its edges
// can be an if-then-else structure or a switch
string dfaStateName = "dfaState";
string dfaLoopbackStateName = "dfaLoopbackState";
string dfaOptionalBlockStateName = "dfaOptionalBlockState";
string dfaEdgeName = "dfaEdge";
if ( _parentGenerator.CanGenerateSwitch( s ) )
{
dfaStateName = "dfaStateSwitch";
dfaLoopbackStateName = "dfaLoopbackStateSwitch";
dfaOptionalBlockStateName = "dfaOptionalBlockStateSwitch";
dfaEdgeName = "dfaEdgeSwitch";
}
StringTemplate dfaST = templates.GetInstanceOf( dfaStateName );
if ( dfa.NFADecisionStartState.decisionStateType == NFAState.LOOPBACK )
{
dfaST = templates.GetInstanceOf( dfaLoopbackStateName );
}
else if ( dfa.NFADecisionStartState.decisionStateType == NFAState.OPTIONAL_BLOCK_START )
{
dfaST = templates.GetInstanceOf( dfaOptionalBlockStateName );
}
dfaST.SetAttribute( "k", k );
dfaST.SetAttribute( "stateNumber", s.StateNumber );
dfaST.SetAttribute( "semPredState",
s.IsResolvedWithPredicates );
/*
string description = dfa.getNFADecisionStartState().Description;
description = parentGenerator.target.getTargetStringLiteralFromString( description );
//System.Console.Out.WriteLine( "DFA: " + description + " associated with AST " + dfa.getNFADecisionStartState() );
if ( description != null )
{
dfaST.SetAttribute( "description", description );
}
*/
int EOTPredicts = NFA.INVALID_ALT_NUMBER;
DFAState EOTTarget = null;
//System.Console.Out.WriteLine( "DFA state " + s.stateNumber );
for ( int i = 0; i < s.NumberOfTransitions; i++ )
{
Transition edge = (Transition)s.GetTransition( i );
//System.Console.Out.WriteLine( "edge " + s.stateNumber + "-" + edge.label.ToString() + "->" + edge.target.stateNumber );
if ( edge.Label.Atom == Label.EOT )
{
// don't generate a real edge for EOT; track alt EOT predicts
// generate that prediction in the else clause as default case
EOTTarget = (DFAState)edge.Target;
EOTPredicts = EOTTarget.GetUniquelyPredictedAlt();
/*
System.Console.Out.WriteLine("DFA s"+s.stateNumber+" EOT goes to s"+
edge.target.stateNumber+" predicates alt "+
EOTPredicts);
*/
continue;
}
StringTemplate edgeST = templates.GetInstanceOf( dfaEdgeName );
// If the template wants all the label values delineated, do that
if ( edgeST.impl.TryGetFormalArgument( "labels" ) != null )
{
List<string> labels = edge.Label.Set.Select( value => _parentGenerator.GetTokenTypeAsTargetLabel( value ) ).ToList();
edgeST.SetAttribute( "labels", labels );
}
else
{ // else create an expression to evaluate (the general case)
edgeST.SetAttribute( "labelExpr",
_parentGenerator.GenLabelExpr( templates, edge, k ) );
}
// stick in any gated predicates for any edge if not already a pred
if ( !edge.Label.IsSemanticPredicate )
{
DFAState target = (DFAState)edge.Target;
SemanticContext preds =
target.GetGatedPredicatesInNFAConfigurations();
if ( preds != null )
{
//System.Console.Out.WriteLine( "preds=" + target.getGatedPredicatesInNFAConfigurations() );
StringTemplate predST = preds.GenExpr( _parentGenerator,
_parentGenerator.Templates,
dfa );
edgeST.SetAttribute( "predicates", predST );
}
}
StringTemplate targetST =
WalkFixedDFAGeneratingStateMachine( templates,
dfa,
(DFAState)edge.Target,
k + 1 );
edgeST.SetAttribute( "targetState", targetST );
dfaST.SetAttribute( "edges", edgeST );
//System.Console.Out.WriteLine( "back to DFA " + dfa.decisionNumber + "." + s.stateNumber );
}
// HANDLE EOT EDGE
if ( EOTPredicts != NFA.INVALID_ALT_NUMBER )
{
// EOT unique predicts an alt
dfaST.SetAttribute( "eotPredictsAlt", EOTPredicts );
}
else if ( EOTTarget != null && EOTTarget.NumberOfTransitions > 0 )
{
// EOT state has transitions so must split on predicates.
// Generate predicate else-if clauses and then generate
// NoViableAlt exception as else clause.
// Note: these predicates emanate from the EOT target state
// rather than the current DFAState s so the error message
// might be slightly misleading if you are looking at the
// state number. Predicates emanating from EOT targets are
// hoisted up to the state that has the EOT edge.
for ( int i = 0; i < EOTTarget.NumberOfTransitions; i++ )
{
Transition predEdge = (Transition)EOTTarget.GetTransition( i );
StringTemplate edgeST = templates.GetInstanceOf( dfaEdgeName );
edgeST.SetAttribute( "labelExpr",
_parentGenerator.GenSemanticPredicateExpr( templates, predEdge ) );
// the target must be an accept state
//System.Console.Out.WriteLine( "EOT edge" );
StringTemplate targetST =
WalkFixedDFAGeneratingStateMachine( templates,
dfa,
(DFAState)predEdge.Target,
k + 1 );
edgeST.SetAttribute( "targetState", targetST );
dfaST.SetAttribute( "edges", edgeST );
}
}
return dfaST;
}
public virtual DFAState NewState()
{
DFAState n = new DFAState( this );
n.StateNumber = _stateCounter;
_stateCounter++;
_states.Resize( n.StateNumber + 1 );
_states[n.StateNumber] = n; // track state num to state
return n;
}
private void WalkCreatingDfaDgml(DFAState dfaState)
{
if (!_markedStates.Add(dfaState.StateNumber))
return;
// first add this node
string nodeCategory;
if (dfaState.IsAcceptState)
{
nodeCategory = Categories.StopState;
}
else
{
nodeCategory = Categories.State;
}
XElement node = new XElement(Elements.Node,
new XAttribute(Attributes.Id, "state_" + dfaState.StateNumber),
new XAttribute(Attributes.Label, GetStateLabel(dfaState)),
new XAttribute(Attributes.Category, nodeCategory));
_nodes.Add(dfaState, node);
if (GroupNodes)
_extraLinks.Add(CreateContainmentLink(_groupId, "state_" + dfaState.StateNumber));
// make an edge for each transition
for (int i = 0; i < dfaState.NumberOfTransitions; i++)
{
Transition edge = dfaState.GetTransition(i);
if (StripNonreducedStates)
{
DFAState target = edge.Target as DFAState;
// don't generate nodes for terminal states
if (target != null && target.AcceptStateReachable != Reachable.Yes)
continue;
}
string edgeCategory = Categories.Edge;
XElement edgeElement = new XElement(Elements.Link,
new XAttribute(Attributes.Source, "state_" + dfaState.StateNumber),
new XAttribute(Attributes.Target, "state_" + edge.Target.StateNumber),
new XAttribute(Attributes.Category, edgeCategory),
new XAttribute(Attributes.Label, GetEdgeLabel(edge)));
_links.Add(new KeyValuePair<State, Transition>(dfaState, edge), edgeElement);
WalkCreatingDfaDgml((DFAState)edge.Target);
}
}
/** Add a transition from this state to target with label. Return
* the transition number from 0..n-1.
*/
public virtual int AddTransition(DFAState target, Label label)
{
_transitions.Add(new Transition(label, target));
return(_transitions.Count - 1);
}
public virtual void SetAcceptState( int alt, DFAState acceptState )
{
_altToAcceptState[alt] = acceptState;
}
/** Do a depth-first walk of the state machine graph and
* fill a DOT description template. Keep filling the
* states and edges attributes.
*/
protected virtual void WalkCreatingDFADOT( StringTemplate dot,
DFAState s )
{
if ( markedStates.Contains( s.stateNumber ) )
{
return; // already visited this node
}
markedStates.Add( s.stateNumber ); // mark this node as completed.
// first add this node
StringTemplate st;
if ( s.IsAcceptState )
{
st = stlib.GetInstanceOf( Path.Combine( dfaTemplateDirectoryName, "stopstate" ) );
}
else
{
st = stlib.GetInstanceOf( Path.Combine( dfaTemplateDirectoryName, "state" ) );
}
st.SetAttribute( "name", GetStateLabel( s ) );
dot.SetAttribute( "states", st );
// make a DOT edge for each transition
for ( int i = 0; i < s.NumberOfTransitions; i++ )
{
Transition edge = (Transition)s.Transition( i );
//Console.Out.WriteLine( "dfa " + s.dfa.decisionNumber + " edge from s"
// + s.stateNumber + " [" + i + "] of " + s.NumberOfTransitions );
if ( StripNonreducedStates )
{
if ( edge.target is DFAState &&
( (DFAState)edge.target ).AcceptStateReachable != DFA.REACHABLE_YES )
{
continue; // don't generate nodes for terminal states
}
}
st = stlib.GetInstanceOf( Path.Combine( dfaTemplateDirectoryName, "edge" ) );
st.SetAttribute( "label", GetEdgeLabel( edge ) );
st.SetAttribute( "src", GetStateLabel( s ) );
st.SetAttribute( "target", GetStateLabel( edge.target ) );
st.SetAttribute( "arrowhead", arrowhead );
dot.SetAttribute( "edges", st );
WalkCreatingDFADOT( dot, (DFAState)edge.target ); // keep walkin'
}
}
public virtual void SetState( int stateNumber, DFAState d )
{
_states[stateNumber] = d;
}
protected virtual HashSet<object> GetDFAPathStatesToTarget( DFAState targetState )
{
HashSet<object> dfaStates = new HashSet<object>();
_stateReachable = new Dictionary<int, Reachable>();
if ( _dfa == null || _dfa.StartState == null )
{
return dfaStates;
}
bool reaches = ReachesState( _dfa.StartState, targetState, dfaStates );
return dfaStates;
}
/** Add a new DFA state to this DFA if not already present.
* To force an acyclic, fixed maximum depth DFA, just always
* return the incoming state. By not reusing old states,
* no cycles can be created. If we're doing fixed k lookahead
* don't updated uniqueStates, just return incoming state, which
* indicates it's a new state.
*/
protected internal virtual DFAState AddState( DFAState d )
{
if ( UserMaxLookahead > 0 )
{
return d;
}
// does a DFA state exist already with everything the same
// except its state number?
DFAState existing;
_uniqueStates.TryGetValue(d, out existing);
if ( existing != null )
{
/*
[email protected]("state "+d.stateNumber+" exists as state "+
existing.stateNumber);
*/
// already there...get the existing DFA state
return existing;
}
// if not there, then add new state.
_uniqueStates[d] = d;
_numberOfStates++;
return d;
}
// T R A C K I N G M E T H O D S
/** Report the fact that DFA state d is not a state resolved with
* predicates and yet it has no emanating edges. Usually this
* is a result of the closure/reach operations being unable to proceed
*/
public virtual void ReportDanglingState(DFAState d)
{
_danglingStates.Add(d);
}
/** Add a transition from this state to target with label. Return
* the transition number from 0..n-1.
*/
public virtual int AddTransition( DFAState target, Label label )
{
_transitions.Add( new Transition( label, target ) );
return _transitions.Count - 1;
}
