Zero-length start patterns work.

Add zero-length captures back into OnigRegEx.BuildCaptureIndices to see zero length captures. Handle zero-length captures by continuing to scan line. Does not handle infinite loop possibility yet.

native/v8_extensions/onig_reg_exp.mm

@@ -58,7 +58,7 @@ public:
     for (int index = 0; index < resultCount; index++) {
       int captureLength = [result lengthAt:index];
       int captureStart = [result locationAt:index];
-      if (captureLength == 0) continue;
+
       array->SetValue(i++, CefV8Value::CreateInt(index));
       array->SetValue(i++, CefV8Value::CreateInt(captureStart));
       array->SetValue(i++, CefV8Value::CreateInt(captureStart + captureLength));
@@ -104,7 +104,7 @@ bool OnigRegExp::Execute(const CefString& name,
       if (captureIndices->IsNull()) continue;
       
       if (bestIndex == -1 || captureIndices->GetValue(1)->GetIntValue() < captureIndicesForBestIndex->GetValue(1)->GetIntValue()) {
-          bestIndex = i;
+        bestIndex = i;
         captureIndicesForBestIndex = captureIndices;
         if (captureIndices->GetValue(1)->GetIntValue() == 0) break; // If the match starts at 0, just use it!
       }

src/app/text-mate-grammar.coffee

@@ -49,7 +49,7 @@ class TextMateGrammar
 
         tokens.push(nextTokens...)
         position = tokensEndPosition
-      else
+      else if tokensEndPosition - tokensStartPosition != 0 # break unless it was a zero length match
         tokens.push
           value: line[position...line.length]
           scopes: scopes
@@ -147,14 +147,12 @@ class Pattern
     scopes.push(@scopeName) unless @popRule
 
     if @captures
-      parentCapture = captureIndices[0..2]
-      childCaptures = captureIndices[3..]
       tokens = @getTokensForCaptureIndices(line, captureIndices, scopes)
     else
       [start, end] = captureIndices[1..2]
       zeroLengthMatch = end == start
       if zeroLengthMatch
-        tokens = []
+        tokens = null
       else
         tokens = [{ value: line[start...end], scopes: scopes }]
 
@@ -176,6 +174,10 @@ class Pattern
     while captureIndices.length and captureIndices[1] < parentCaptureEnd
       [childCaptureIndex, childCaptureStart, childCaptureEnd] = captureIndices
 
+      if childCaptureEnd - childCaptureStart == 0 # An empty capture, so it can't contain any tokens
+        shiftCapture(captureIndices)
+        continue
+
       if childCaptureStart > previousChildCaptureEnd
         tokens.push
           value: line[previousChildCaptureEnd...childCaptureStart]