/// <summary>
/// Yields each of the possible matches of the regex from this point onwards as a CharSetString.
/// </summary>
/// <param name="charIdx">
/// The current index of the match in the string
/// </param>
/// <param name="currentConstraints">
/// The prior constraints on any matches
/// </param>
public override IEnumerable<CharSetString> GeneratePossibleMatches(int charIdx, CharSetString currentConstraints)
{
if (CurrentMatch != null)
{
throw new InvalidOperationException("There is already a match in progress");
}
foreach (var choice in Choices)
{
var first = choice.First();
foreach (var choiceMatchGen in first.GeneratePossibleMatches(charIdx, currentConstraints))
{
// choiceMatch may be modified later on (see RegexBackReference), so we promote it
// to a RevertibleCharSetString
var choiceMatch = new RevertibleCharSetString(choiceMatchGen);
CurrentMatch = choiceMatch;
foreach (var remainderMatch in
Next.GeneratePossibleMatches(
charIdx + choiceMatch.Length,
currentConstraints))
{
yield return choiceMatch.Concat(remainderMatch);
}
CurrentMatch = null;
}
}
}
public IEnumerable<CharSetString> GeneratePossibleMatches(int charIdx, CharSetString currentConstraints)
{
if (charIdx == currentConstraints.Length)
{
yield return CharSetString.EmptyString();
}
}
public override IEnumerable<CharSetString> GeneratePossibleMatches(int charIdx, CharSetString currentConstraints)
{
// Is the groupMatch applicable here?
//
// The constraints here retrospectively modify the earlier match -- any matching string
// must match both here and before, i.e.
// a regex like "(.)\1" applied to ".A" must become "AA"
//
// We bookmark the previous match, so that we can put things back how we found them
// after iterating over this possible path.
var previousGroupMatch = Group.CurrentMatch;
previousGroupMatch.Bookmark();
var i = 0;
foreach (var groupMatchChar in previousGroupMatch)
{
if (charIdx + i >= currentConstraints.Length)
{
goto noMatch;
}
try
{
groupMatchChar.Intersect(currentConstraints[charIdx + i]);
}
catch (CharSet.EmptyIntersectionException)
{
goto noMatch;
}
i++;
}
foreach (var remainderMatch in
Next.GeneratePossibleMatches(
charIdx + previousGroupMatch.Length,
currentConstraints))
{
// The value returned here is valid only briefly: we will reuse the
// same strings in the next element.
// See comments on RegexNonTerminalAtom.GeneratePossibleMatches
yield return previousGroupMatch.Concat(remainderMatch);
}
noMatch:
previousGroupMatch.RevertToBookmark();
}
/// <summary>
/// Yields each of the possible matches of the regex from this point onwards as a CharSetString.
/// </summary>
/// <param name="charIdx">
/// The current index of the match in the string
/// </param>
/// <param name="currentConstraints">
/// The prior constraints on any matches
/// </param>
public override IEnumerable<CharSetString> GeneratePossibleMatches(int charIdx, CharSetString currentConstraints)
{
if (MinReps == 0)
{
foreach (var nextMatch in Next.GeneratePossibleMatches(charIdx, currentConstraints))
{
yield return nextMatch;
}
}
Inner.Next = new RegexEmptyMatchTerminalAtom();
var currentInnerMatches = new List<CharSetString> { CharSetString.EmptyString() };
for (int innerMatchCount = 1; innerMatchCount <= (MaxReps ?? Int32.MaxValue); innerMatchCount++)
{
var newInnerMatches = new List<CharSetString>();
foreach (var currentInnerMatch in currentInnerMatches)
{
// TODO: could group the currentInnerMatches by length here, to save re-computing
// the following repeatedly for the same arguments in some cases
foreach (var nextInnerMatch in Inner.GeneratePossibleMatches(
charIdx + currentInnerMatch.Length,
currentConstraints))
{
var newInnerMatch = currentInnerMatch.Concat(nextInnerMatch);
newInnerMatches.Add(newInnerMatch);
if (innerMatchCount >= MinReps)
{
foreach (var nextMatch in Next.GeneratePossibleMatches(
charIdx + newInnerMatch.Length, currentConstraints))
{
yield return newInnerMatch.Concat(nextMatch);
}
}
}
}
currentInnerMatches = newInnerMatches;
if (!currentInnerMatches.Any())
{
break;
}
}
}
/// <summary>
/// Yields each of the possible matches of the regex from this point onwards as a CharSetString.
/// </summary>
/// <param name="charIdx">
/// The current index of the match in the string
/// </param>
/// <param name="currentConstraints">
/// The prior constraints on any matches
/// </param>
public override IEnumerable<CharSetString> GeneratePossibleMatches(int charIdx, CharSetString currentConstraints)
{
if (charIdx >= currentConstraints.Length)
{
yield break; // no match
}
var thisCharSet = currentConstraints[charIdx].Clone();
try
{
thisCharSet.Intersect(CharSet);
}
catch (CharSet.EmptyIntersectionException)
{
yield break; // no match
}
foreach (var remainderMatch in Next.GeneratePossibleMatches(charIdx + 1, currentConstraints))
{
yield return CharSetString.Cons(thisCharSet, remainderMatch);
}
}
/// <param name="clues">
/// The clues as a 3xN grid
/// </param>
public HexRegexCrossword(Regex[,] clues)
{
if (3 != clues.GetUpperBound(0) + 1 || 0 != clues.GetLowerBound(0)
|| 0 != clues.GetLowerBound(1))
{
throw new ArgumentException("The clue array must be 3 X rowCount");
}
Clues = clues;
RowCount = clues.GetUpperBound(1) + 1;
SideLength = (RowCount + 1)/2;
GridRows = new CharSetString[3, RowCount];
// Build up a grid of cells by Q/R.
// The max coord will be < +/- sideLength
// Since coords may be negative, this array is offset by +sideLength
_cellsByQROffsetBySideLength = new CharSet[2 * SideLength, 2 * SideLength];
for (int axis = 0; axis < 3; axis++)
{
for (int idx = -(SideLength - 1); idx <= (SideLength - 1); idx++)
{
var row = new List<CharSet>();
for (int offset = 0;; offset++)
{
var qr = AxisIdxOffsetToQR(axis, idx, offset);
var cell = GetCellByQR(qr);
if (cell == null) // qr is out of range
{
break;
}
row.Add(cell);
}
GridRows[axis, idx + (SideLength - 1)] = new CharSetString(row);
}
}
}
/// <summary> /// Enumerates the possible matches for this regex component at the given starting index and /// under the given constraints. /// /// Careful: the returned CharSetStrings are only valid when they are first returned from the /// iterator. Parts of the string are shared between successive return values. You must copy /// or consume the output while the iteration is proceeding. /// /// See RegexBackReference for more on this. /// </summary> /// <param name="charIdx"></param> /// <param name="currentConstraints"></param> /// <returns></returns> public abstract IEnumerable<CharSetString> GeneratePossibleMatches(int charIdx, CharSetString currentConstraints);
/// <summary>
/// Given a string of possible characters, attempts to constrain the possibilities
/// to only strings which match this regex.
///
/// Returns true if any changes were made.
/// </summary>
public bool AddConstraints(CharSetString currentConstraints)
{
var first = Atoms.First();
var possibilitiesSeen = CharSetString.EmptySetsStringOfLength(currentConstraints.Length);
foreach (var possibility in first.GeneratePossibleMatches(0, currentConstraints))
{
possibilitiesSeen.Union(possibility);
}
return currentConstraints.Intersect(possibilitiesSeen);
}
public IEnumerable<CharSetString> GeneratePossibleMatches(int charIdx, CharSetString currentConstraints)
{
return new[] { CharSetString.EmptyString() };
}
