Merge pull request #359 from MagLev/johnnyt/sample

Adds Array#sample for the basic use case (single random element)

spec/tags/core/array/sample_tags.txt

@@ -1,22 +1,19 @@
-fails:Array#sample selects a random value from the array
-fails:Array#sample returns nil for empty arrays
-fails:Array#sample passed a number n as an argument raises ArgumentError for a negative n
-fails:Array#sample passed a number n as an argument returns different random values from the array
-fails:Array#sample passed a number n as an argument tries to convert n to an Integer using #to_int
-fails:Array#sample passed a number n as an argument returns all values with n big enough
-fails:Array#sample passed a number n as an argument returns [] for empty arrays or if n <= 0
-fails:Array#sample passed a number n as an argument does not return subclass instances with Array subclass
 fails:Array#sample selects a value from the array
 fails:Array#sample returns a distribution of results
+fails:Array#sample returns nil for empty arrays
 fails:Array#sample returns only one element
 fails:Array#sample returns proper array size
 fails:Array#sample attempts coercion via #to_hash
 fails:Array#sample uses default random generator
 fails:Array#sample uses given random generator
 fails:Array#sample uses default random generator and return proper array size
 fails:Array#sample uses given random generator and return proper array size
+fails:Array#sample passed a number n as an argument raises ArgumentError for a negative n
 fails:Array#sample passed a number n as an argument selects values from the array
 fails:Array#sample passed a number n as an argument does not return the same value if the array is unique
 fails:Array#sample passed a number n as an argument may return the same value if the array is not unique
 fails:Array#sample passed a number n as an argument returns a distribution of results
+fails:Array#sample passed a number n as an argument tries to convert n to an Integer using #to_int
 fails:Array#sample passed a number n as an argument returns all values when n >= array size
+fails:Array#sample passed a number n as an argument returns [] for empty arrays or if n <= 0
+fails:Array#sample passed a number n as an argument does not return subclass instances with Array subclass

src/kernel/bootstrap/Array.rb

@@ -1513,6 +1513,13 @@ def rindex(element)
 
   primitive_nobridge '__remove_from_to_', 'removeFrom:to:'
 
+  # Let's get the basic use case working - just pulling a single random element
+  # Check out https://github.com/rubinius/rubinius/blob/master/kernel/common/array.rb#L1286 for
+  # the Rubinius implementation
+  def sample(count=MaglevUndefined, options=MaglevUndefined)
+    return at Kernel.rand(size)
+  end
+
   def shift(count=MaglevUndefined)  # added in 1.8.7
     if count._equal?(MaglevUndefined) 
       return self.__shift