private void ThrowParseException(LookAheadSet set)
{
ArrayList list = new ArrayList();
// Read tokens until mismatch
while (set.IsNext(this, 1))
{
set = set.CreateNextSet(NextToken().Id);
}
// Find next token descriptions
var initials = set.GetInitialTokens();
for (int i = 0; i < initials.Length; i++)
{
list.Add(GetTokenDescription(initials[i]));
}
// Create exception
var token = NextToken();
throw new ParseException(ParseException.ErrorType.UNEXPECTED_TOKEN,
token.ToShortString(),
list,
token.StartLine,
token.StartColumn);
}
private LookAheadSet FindLookAhead(ProductionPattern pattern,
int length,
CallStack stack,
LookAheadSet filter)
{
// Check for infinite loop
if (stack.Contains(pattern.Name, length))
{
throw new ParserCreationException(
ParserCreationException.ErrorType.INFINITE_LOOP,
pattern.Name,
(String)null);
}
// Find pattern look-ahead
stack.Push(pattern.Name, length);
var result = new LookAheadSet(length);
for (int i = 0; i < pattern.Count; i++)
{
var temp = FindLookAhead(pattern[i],
length,
0,
stack,
filter);
result.AddAll(temp);
}
stack.Pop();
return(result);
}
private LookAheadSet FindLookAhead(ProductionPatternElement elem,
int length,
int dummy,
CallStack stack,
LookAheadSet filter)
{
LookAheadSet result;
if (elem.IsToken())
{
result = new LookAheadSet(length);
result.Add(elem.Id);
}
else
{
var pattern = GetPattern(elem.Id);
result = FindLookAhead(pattern, length, stack, filter);
if (stack.Contains(pattern.Name))
{
result = result.CreateRepetitive();
}
}
return(result);
}
public void AddAll(LookAheadSet set)
{
for (int i = 0; i < set._elements.Count; i++)
{
Add((Sequence)set._elements[i]);
}
}
public void RemoveAll(LookAheadSet set)
{
for (int i = 0; i < set._elements.Count; i++)
{
Remove((Sequence)set._elements[i]);
}
}
public LookAheadSet CreateFilter(LookAheadSet set)
{
LookAheadSet result = new LookAheadSet(_maxLength);
// Handle special cases
if (this.Size() <= 0 || set.Size() <= 0)
{
return(this);
}
// Create combinations
for (int i = 0; i < _elements.Count; i++)
{
var first = (Sequence)_elements[i];
for (int j = 0; j < set._elements.Count; j++)
{
var second = (Sequence)set._elements[j];
if (first.StartsWith(second))
{
result.Add(first.Subsequence(second.Length()));
}
}
}
return(result);
}
public ProductionPattern(int id, string name)
{
this._id = id;
this._name = name;
this._synthetic = false;
this._alternatives = new ArrayList();
this._defaultAlt = -1;
this._lookAhead = null;
}
public bool IsOverlap(LookAheadSet set)
{
for (int i = 0; i < _elements.Count; i++)
{
if (set.IsOverlap((Sequence)_elements[i]))
{
return(true);
}
}
return(false);
}
public bool Intersects(LookAheadSet set)
{
for (int i = 0; i < _elements.Count; i++)
{
if (set.Contains((Sequence)_elements[i]))
{
return(true);
}
}
return(false);
}
private LookAheadSet FindConflicts(string pattern,
string location,
LookAheadSet set1,
LookAheadSet set2)
{
var result = set1.CreateIntersection(set2);
if (result.IsRepetitive())
{
ThrowAmbiguityException(pattern, location, result);
}
return(result);
}
private bool IsNext(ProductionPattern pattern)
{
LookAheadSet set = pattern.LookAhead;
if (set == null)
{
return(false);
}
else
{
return(set.IsNext(this));
}
}
private bool IsNext(ProductionPatternAlternative alt)
{
LookAheadSet set = alt.LookAhead;
if (set == null)
{
return(false);
}
else
{
return(set.IsNext(this));
}
}
public LookAheadSet CreateOverlaps(LookAheadSet set)
{
LookAheadSet result = new LookAheadSet(_maxLength);
for (int i = 0; i < _elements.Count; i++)
{
var seq = (Sequence)_elements[i];
if (set.IsOverlap(seq))
{
result.Add(seq);
}
}
return(result);
}
public LookAheadSet CreateNextSet(int token)
{
LookAheadSet result = new LookAheadSet(_maxLength - 1);
for (int i = 0; i < _elements.Count; i++)
{
var seq = (Sequence)_elements[i];
var value = seq.GetToken(0);
if (value != null && token == (int)value)
{
result.Add(seq.Subsequence(1));
}
}
return(result);
}
private bool IsNext(ProductionPatternElement elem)
{
LookAheadSet set = elem.LookAhead;
if (set != null)
{
return(set.IsNext(this));
}
else if (elem.IsToken())
{
return(elem.IsMatch(PeekToken(0)));
}
else
{
return(IsNext(GetPattern(elem.Id)));
}
}
public LookAheadSet CreateRepetitive()
{
LookAheadSet result = new LookAheadSet(_maxLength);
for (int i = 0; i < _elements.Count; i++)
{
var seq = (Sequence)_elements[i];
if (seq.IsRepetitive())
{
result.Add(seq);
}
else
{
result.Add(new Sequence(true, seq));
}
}
return(result);
}
private LookAheadSet FindLookAhead(ProductionPatternAlternative alt,
int length,
int pos,
CallStack stack,
LookAheadSet filter)
{
LookAheadSet follow;
// Check trivial cases
if (length <= 0 || pos >= alt.Count)
{
return(new LookAheadSet(0));
}
// Find look-ahead for this element
var first = FindLookAhead(alt[pos], length, stack, filter);
if (alt[pos].MinCount == 0)
{
first.AddEmpty();
}
// Find remaining look-ahead
if (filter == null)
{
length -= first.GetMinLength();
if (length > 0)
{
follow = FindLookAhead(alt, length, pos + 1, stack, null);
first = first.CreateCombination(follow);
}
}
else if (filter.IsOverlap(first))
{
var overlaps = first.CreateOverlaps(filter);
length -= overlaps.GetMinLength();
filter = filter.CreateFilter(overlaps);
follow = FindLookAhead(alt, length, pos + 1, stack, filter);
first.RemoveAll(overlaps);
first.AddAll(overlaps.CreateCombination(follow));
}
return(first);
}
private LookAheadSet FindLookAhead(ProductionPatternElement elem,
int length,
CallStack stack,
LookAheadSet filter)
{
// Find initial element look-ahead
var first = FindLookAhead(elem, length, 0, stack, filter);
var result = new LookAheadSet(length);
result.AddAll(first);
if (filter == null || !filter.IsOverlap(result))
{
return(result);
}
// Handle element repetitions
if (elem.MaxCount == Int32.MaxValue)
{
first = first.CreateRepetitive();
}
var max = elem.MaxCount;
if (length < max)
{
max = length;
}
for (int i = 1; i < max; i++)
{
first = first.CreateOverlaps(filter);
if (first.Size() <= 0 || first.GetMinLength() >= length)
{
break;
}
var follow = FindLookAhead(elem,
length,
0,
stack,
filter.CreateFilter(first));
first = first.CreateCombination(follow);
result.AddAll(first);
}
return(result);
}
public LookAheadSet CreateIntersection(LookAheadSet set)
{
LookAheadSet result = new LookAheadSet(_maxLength);
for (int i = 0; i < _elements.Count; i++)
{
var seq1 = (Sequence)_elements[i];
var seq2 = set.FindSequence(seq1);
if (seq2 != null && seq1.IsRepetitive())
{
result.Add(seq2);
}
else if (seq2 != null)
{
result.Add(seq1);
}
}
return(result);
}
private LookAheadSet FindConflicts(ProductionPattern pattern,
int maxLength)
{
LookAheadSet result = new LookAheadSet(maxLength);
for (int i = 0; i < pattern.Count; i++)
{
var set1 = pattern[i].LookAhead;
for (int j = 0; j < i; j++)
{
var set2 = pattern[j].LookAhead;
result.AddAll(set1.CreateIntersection(set2));
}
}
if (result.IsRepetitive())
{
ThrowAmbiguityException(pattern.Name, null, result);
}
return(result);
}
private void ThrowAmbiguityException(string pattern,
string location,
LookAheadSet set)
{
ArrayList list = new ArrayList();
// Find next token descriptions
var initials = set.GetInitialTokens();
for (int i = 0; i < initials.Length; i++)
{
list.Add(GetTokenDescription(initials[i]));
}
// Create exception
throw new ParserCreationException(
ParserCreationException.ErrorType.INHERENT_AMBIGUITY,
pattern,
location,
list);
}
private LookAheadSet FindUnion(ProductionPattern pattern)
{
LookAheadSet result;
int length = 0;
int i;
for (i = 0; i < pattern.Count; i++)
{
result = pattern[i].LookAhead;
if (result.GetMaxLength() > length)
{
length = result.GetMaxLength();
}
}
result = new LookAheadSet(length);
for (i = 0; i < pattern.Count; i++)
{
result.AddAll(pattern[i].LookAhead);
}
return(result);
}
public ProductionPatternElement(bool isToken,
int id,
int min,
int max)
{
this._token = isToken;
this._id = id;
if (min < 0)
{
min = 0;
}
this._min = min;
if (max <= 0)
{
max = Int32.MaxValue;
}
else if (max < min)
{
max = min;
}
this._max = max;
this._lookAhead = null;
}
public LookAheadSet CreateCombination(LookAheadSet set)
{
LookAheadSet result = new LookAheadSet(_maxLength);
// Handle special cases
if (this.Size() <= 0)
{
return(set);
}
else if (set.Size() <= 0)
{
return(this);
}
// Create combinations
for (int i = 0; i < _elements.Count; i++)
{
var first = (Sequence)_elements[i];
if (first.Length() >= _maxLength)
{
result.Add(first);
}
else if (first.Length() <= 0)
{
result.AddAll(set);
}
else
{
for (int j = 0; j < set._elements.Count; j++)
{
var second = (Sequence)set._elements[j];
result.Add(first.Concat(_maxLength, second));
}
}
}
return(result);
}
private void CalculateLookAhead(ProductionPattern pattern)
{
ProductionPatternAlternative alt;
LookAheadSet previous = new LookAheadSet(0);
int length = 1;
int i;
CallStack stack = new CallStack();
// Calculate simple look-ahead
stack.Push(pattern.Name, 1);
var result = new LookAheadSet(1);
var alternatives = new LookAheadSet[pattern.Count];
for (i = 0; i < pattern.Count; i++)
{
alt = pattern[i];
alternatives[i] = FindLookAhead(alt, 1, 0, stack, null);
alt.LookAhead = alternatives[i];
result.AddAll(alternatives[i]);
}
if (pattern.LookAhead == null)
{
pattern.LookAhead = result;
}
var conflicts = FindConflicts(pattern, 1);
// Resolve conflicts
while (conflicts.Size() > 0)
{
length++;
stack.Clear();
stack.Push(pattern.Name, length);
conflicts.AddAll(previous);
for (i = 0; i < pattern.Count; i++)
{
alt = pattern[i];
if (alternatives[i].Intersects(conflicts))
{
alternatives[i] = FindLookAhead(alt,
length,
0,
stack,
conflicts);
alt.LookAhead = alternatives[i];
}
if (alternatives[i].Intersects(conflicts))
{
if (pattern.DefaultAlternative == null)
{
pattern.DefaultAlternative = alt;
}
else if (pattern.DefaultAlternative != alt)
{
result = alternatives[i].CreateIntersection(conflicts);
ThrowAmbiguityException(pattern.Name,
null,
result);
}
}
}
previous = conflicts;
conflicts = FindConflicts(pattern, length);
}
// Resolve conflicts inside rules
for (i = 0; i < pattern.Count; i++)
{
CalculateLookAhead(pattern[i], 0);
}
}
private void CalculateLookAhead(ProductionPatternAlternative alt,
int pos)
{
LookAheadSet previous = new LookAheadSet(0);
int length = 1;
// Check trivial cases
if (pos >= alt.Count)
{
return;
}
// Check for non-optional element
var pattern = alt.Pattern;
var elem = alt[pos];
if (elem.MinCount == elem.MaxCount)
{
CalculateLookAhead(alt, pos + 1);
return;
}
// Calculate simple look-aheads
var first = FindLookAhead(elem, 1, new CallStack(), null);
var follow = FindLookAhead(alt, 1, pos + 1, new CallStack(), null);
// Resolve conflicts
var location = "at position " + (pos + 1);
var conflicts = FindConflicts(pattern.Name,
location,
first,
follow);
while (conflicts.Size() > 0)
{
length++;
conflicts.AddAll(previous);
first = FindLookAhead(elem,
length,
new CallStack(),
conflicts);
follow = FindLookAhead(alt,
length,
pos + 1,
new CallStack(),
conflicts);
first = first.CreateCombination(follow);
elem.LookAhead = first;
if (first.Intersects(conflicts))
{
first = first.CreateIntersection(conflicts);
ThrowAmbiguityException(pattern.Name, location, first);
}
previous = conflicts;
conflicts = FindConflicts(pattern.Name,
location,
first,
follow);
}
// Check remaining elements
CalculateLookAhead(alt, pos + 1);
}
public LookAheadSet(int maxLength, LookAheadSet set)
: this(maxLength)
{
AddAll(set);
}
