Index: Lib/fractions.py
===================================================================
--- Lib/fractions.py	(revision 71785)
+++ Lib/fractions.py	(working copy)
@@ -28,13 +28,14 @@
     (?P<sign>[-+]?)            # an optional sign, then
     (?=\d|\.\d)                # lookahead for digit or .digit
     (?P<num>\d*)               # numerator (possibly empty)
-    (?:                        # followed by an optional
-       /(?P<denom>\d+)         # / and denominator
+    (?:                        # followed by
+       (?:/(?P<denom>\d+))?    # an optional denominator
     |                          # or
-       \.(?P<decimal>\d*)      # decimal point and fractional part
-    )?
+       (?:\.(?P<decimal>\d*))? # an optional fractional part
+       (?:E(?P<exp>[-+]?\d+))? # and optional exponent
+    )
     \s*\Z                      # and optional whitespace to finish
-""", re.VERBOSE)
+""", re.VERBOSE | re.IGNORECASE)
 
 
 class Fraction(numbers.Rational):
@@ -65,22 +66,28 @@
         if not isinstance(numerator, int) and denominator == 1:
             if isinstance(numerator, str):
                 # Handle construction from strings.
-                input = numerator
-                m = _RATIONAL_FORMAT.match(input)
+                m = _RATIONAL_FORMAT.match(numerator)
                 if m is None:
-                    raise ValueError('Invalid literal for Fraction: %r' % input)
-                numerator = m.group('num')
-                decimal = m.group('decimal')
-                if decimal:
-                    # The literal is a decimal number.
-                    numerator = int(numerator + decimal)
-                    denominator = 10**len(decimal)
+                    raise ValueError('Invalid literal for Fraction: %r' %
+                                     numerator)
+                numerator = int(m.group('num') or '0')
+                denom = m.group('denom')
+                if denom:
+                    denominator = int(denom)
                 else:
-                    # The literal is an integer or fraction.
-                    numerator = int(numerator)
-                    # Default denominator to 1.
-                    denominator = int(m.group('denom') or 1)
-
+                    denominator = 1
+                    decimal = m.group('decimal')
+                    if decimal:
+                        scale = 10**len(decimal)
+                        numerator = numerator * scale + int(decimal)
+                        denominator *= scale
+                    exp = m.group('exp')
+                    if exp:
+                        exp = int(exp)
+                        if exp >= 0:
+                            numerator *= 10**exp
+                        else:
+                            denominator *= 10**-exp
                 if m.group('sign') == '-':
                     numerator = -numerator
 
Index: Lib/test/test_fractions.py
===================================================================
--- Lib/test/test_fractions.py	(revision 71785)
+++ Lib/test/test_fractions.py	(working copy)
@@ -78,7 +78,11 @@
         self.assertEquals((-16, 5), _components(F(" -3.2 ")))
         self.assertEquals((-3, 1), _components(F(" -3. ")))
         self.assertEquals((3, 5), _components(F(" .6 ")))
-
+        self.assertEquals((1, 3125), _components(F("32.e-5")))
+        self.assertEquals((1000000, 1), _components(F("1e+06")))
+        self.assertEquals((-12300, 1), _components(F("-1.23e4")))
+        self.assertEquals((0, 1), _components(F(" .0e+0\t")))
+                          
         self.assertRaisesMessage(
             ZeroDivisionError, "Fraction(3, 0)",
             F, "3/0")
@@ -101,10 +105,6 @@
             ValueError, "Invalid literal for Fraction: '3a2'",
             F, "3a2")
         self.assertRaisesMessage(
-            # Only parse ordinary decimals, not scientific form.
-            ValueError, "Invalid literal for Fraction: '3.2e4'",
-            F, "3.2e4")
-        self.assertRaisesMessage(
             # Don't accept combinations of decimals and rationals.
             ValueError, "Invalid literal for Fraction: '3/7.2'",
             F, "3/7.2")