Experimental support for RegExp lookbehind.

src/parser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PARSER_H_
 #define V8_PARSER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/compiler.h"  // TODO(titzer): remove this include dependency
@@ skipping 352 matching lines @@
 
  private:
   ZoneList<T*>* list_;
   T* last_;
 };
 
 
 // Accumulates RegExp atoms and assertions into lists of terms and alternatives.
 class RegExpBuilder: public ZoneObject {
  public:
-  explicit RegExpBuilder(Zone* zone);
+  RegExpBuilder(Zone* zone, RegExpTree::ReadDirection read_direction);
   void AddCharacter(uc16 character);
   // "Adds" an empty expression. Does nothing except consume a
   // following quantifier
   void AddEmpty();
   void AddAtom(RegExpTree* tree);
   void AddAssertion(RegExpTree* tree);
   void NewAlternative();  // '|'
   void AddQuantifierToAtom(
       int min, int max, RegExpQuantifier::QuantifierType type);
   RegExpTree* ToRegExp();
 
  private:
   void FlushCharacters();
   void FlushText();
   void FlushTerms();
   Zone* zone() const { return zone_; }
 
   Zone* zone_;
   bool pending_empty_;
   ZoneList<uc16>* characters_;
   BufferedZoneList<RegExpTree, 2> terms_;
   BufferedZoneList<RegExpTree, 2> text_;
   BufferedZoneList<RegExpTree, 2> alternatives_;
+  RegExpTree::ReadDirection read_direction_;
 #ifdef DEBUG
   enum {ADD_NONE, ADD_CHAR, ADD_TERM, ADD_ASSERT, ADD_ATOM} last_added_;
 #define LAST(x) last_added_ = x;
 #else
 #define LAST(x)
 #endif
 };
 
 
 class RegExpParser BASE_EMBEDDED {
  public:
   RegExpParser(FlatStringReader* in, Handle<String>* error, bool multiline_mode,
                bool unicode, Isolate* isolate, Zone* zone);
 
   static bool ParseRegExp(Isolate* isolate, Zone* zone, FlatStringReader* input,
                           bool multiline, bool unicode,
                           RegExpCompileData* result);
 
   RegExpTree* ParsePattern();
   RegExpTree* ParseDisjunction();
   RegExpTree* ParseGroup();
-  RegExpTree* ParseCharacterClass();
+  RegExpTree* ParseCharacterClass(RegExpTree::ReadDirection read_direction);
 
   // Parses a {...,...} quantifier and stores the range in the given
   // out parameters.
   bool ParseIntervalQuantifier(int* min_out, int* max_out);
 
   // Parses and returns a single escaped character.  The character
   // must not be 'b' or 'B' since they are usually handle specially.
   uc32 ParseClassCharacterEscape();
 
   // Checks whether the following is a length-digit hexadecimal number,
@@ skipping 14 matching lines @@
   RegExpTree* ReportError(Vector<const char> message);
   void Advance();
   void Advance(int dist);
   void Reset(int pos);
 
   // Reports whether the pattern might be used as a literal search string.
   // Only use if the result of the parse is a single atom node.
   bool simple();
   bool contains_anchor() { return contains_anchor_; }
   void set_contains_anchor() { contains_anchor_ = true; }
-  int captures_started() { return captures_ == NULL ? 0 : captures_->length(); }
+  int captures_started() { return captures_started_; }
   int position() { return next_pos_ - 1; }
   bool failed() { return failed_; }
 
   static bool IsSyntaxCharacter(uc32 c);
 
   static const int kMaxCaptures = 1 << 16;
   static const uc32 kEndMarker = (1 << 21);
 
  private:
   enum SubexpressionType {
     INITIAL,
     CAPTURE,  // All positive values represent captures.
     POSITIVE_LOOKAHEAD,
     NEGATIVE_LOOKAHEAD,
     GROUPING
   };
 
   class RegExpParserState : public ZoneObject {
    public:
     RegExpParserState(RegExpParserState* previous_state,
                       SubexpressionType group_type,
-                      int disjunction_capture_index,
-                      Zone* zone)
+                      RegExpTree::ReadDirection read_direction,
+                      int disjunction_capture_index, Zone* zone)
         : previous_state_(previous_state),
-          builder_(new(zone) RegExpBuilder(zone)),
+          builder_(new (zone) RegExpBuilder(zone, read_direction)),
           group_type_(group_type),
+          read_direction_(read_direction),
           disjunction_capture_index_(disjunction_capture_index) {}
     // Parser state of containing expression, if any.
     RegExpParserState* previous_state() { return previous_state_; }
     bool IsSubexpression() { return previous_state_ != NULL; }
     // RegExpBuilder building this regexp's AST.
     RegExpBuilder* builder() { return builder_; }
     // Type of regexp being parsed (parenthesized group or entire regexp).
     SubexpressionType group_type() { return group_type_; }
+    // Lookahead or Lookbehind.
+    RegExpTree::ReadDirection read_direction() { return read_direction_; }
     // Index in captures array of first capture in this sub-expression, if any.
     // Also the capture index of this sub-expression itself, if group_type
     // is CAPTURE.
     int capture_index() { return disjunction_capture_index_; }
 
    private:
     // Linked list implementation of stack of states.
     RegExpParserState* previous_state_;
     // Builder for the stored disjunction.
     RegExpBuilder* builder_;
     // Stored disjunction type (capture, look-ahead or grouping), if any.
     SubexpressionType group_type_;
+    // Stored read direction.
+    RegExpTree::ReadDirection read_direction_;
     // Stored disjunction's capture index (if any).
     int disjunction_capture_index_;
   };
 
+  // Return the 1-indexed RegExpCapture object, allocate if necessary.
+  RegExpCapture* GetCapture(int index);
+
   Isolate* isolate() { return isolate_; }
   Zone* zone() const { return zone_; }
 
   uc32 current() { return current_; }
   bool has_more() { return has_more_; }
   bool has_next() { return next_pos_ < in()->length(); }
   uc32 Next();
   FlatStringReader* in() { return in_; }
   void ScanForCaptures();
 
   Isolate* isolate_;
   Zone* zone_;
   Handle<String>* error_;
   ZoneList<RegExpCapture*>* captures_;
   FlatStringReader* in_;
   uc32 current_;
   int next_pos_;
+  int captures_started_;
   // The capture count is only valid after we have scanned for captures.
   int capture_count_;
   bool has_more_;
   bool multiline_;
   bool unicode_;
   bool simple_;
   bool contains_anchor_;
   bool is_scanned_for_captures_;
   bool failed_;
 };
@@ skipping 856 matching lines @@
 
 DoExpression* ParserTraits::ParseDoExpression(bool* ok) {
   return parser_->ParseDoExpression(ok);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSER_H_