Fraction class prototype and test (not to be committed).

runtime/vm/scanner.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/scanner.h"
 
 #include "platform/assert.h"
 #include "vm/dart.h"
 #include "vm/flags.h"
 #include "vm/object.h"
@@ skipping 326 matching lines @@
     // Private identifiers are mangled on a per library basis.
     literal = String::SubString(T, source_, ident_pos, ident_length);
     literal = Symbols::FromConcat(T, literal, private_key_);
   } else {
     literal = Symbols::New(T, source_, ident_pos, ident_length);
   }
   current_token_.literal = &literal;
 }
 
 
-// Parse integer or double number literal of format:
-// NUMBER = INTEGER | DOUBLE
+// Parse integer, rational, or double number literal of format:
+// NUMBER = INTEGER | RATIONAL | DOUBLE
 // INTEGER = D+ | (("0x" | "0X") H+)
+// RATIONAL = ((D+ ["." D*]) | ("." D+)) ("r" | "R")
 // DOUBLE = ((D+ ["." D*]) | ("." D+)) [ EXPONENT ]
 // EXPONENT = ("e" | "E") ["+" | "-"] D+
 void Scanner::ScanNumber(bool dec_point_seen) {
   ASSERT(IsDecimalDigit(c0_));
   char first_digit = c0_;
 
   Recognize(dec_point_seen ? Token::kDOUBLE : Token::kINTEGER);
   if (!dec_point_seen && first_digit == '0' && (c0_ == 'x' || c0_ == 'X')) {
     ReadChar();
     if (!IsHexDigit(c0_)) {
@@ skipping 21 matching lines @@
       if ((c0_ == '-') || (c0_ == '+')) {
         ReadChar();
       }
       if (!IsDecimalDigit(c0_)) {
         ErrorMsg("missing exponent digits");
         return;
       }
       while (IsDecimalDigit(c0_)) {
         ReadChar();
       }
+    } else if ((c0_ == 'r') || (c0_ == 'R')) {
+      Recognize(Token::kRATIONAL);
     }
   }
   if (current_token_.kind != Token::kILLEGAL) {
     intptr_t len = lookahead_pos_ - token_start_;
     const String& str =
         String::ZoneHandle(Z, Symbols::New(T, source_, token_start_, len));
     current_token_.literal = &str;
   }
 }
 
@@ skipping 553 matching lines @@
     keywords_[i].keyword_symbol = &Symbols::Token(token);
 
     int ch = keywords_[i].keyword_chars[0] - 'a';
     if (keywords_char_offset_[ch] == Token::kNumKeywords) {
       keywords_char_offset_[ch] = i;
     }
   }
 }
 
 }  // namespace dart