permutations.rb in epitools-0.5.105

- old
+ new

@@ -1,11 +1,11 @@
 require 'epitools'
 
 class Array
-  
+
   alias_method :mult, :"*"
-  
+
   #
   # Overloaded * operator.
   #
   # Original behaviour:
   #   array * number == <number> copies of array
@@ -24,40 +24,40 @@
       result
     else
       send(:mult, other)
     end
   end
-  
+
   #
   # Multiply the array by itself 'exponent'-times.
   #
   def **(exponent)
     ([self] * exponent).foldl(:*)
   end
-  
+
   def all_pairs(reflexive=false)
     (0...size).each do |a|
       start = reflexive ? a : a+1
       (start...size).each do |b|
         yield self[a], self[b]
       end
     end
   end
-  
+
   enumerable :all_pairs
-  
+
 end
 
 
 #
 # Returns all the `size`-sized selections of the elements from an array.
 #
 # I can't remember why I wrote it like this, but the array you want to
 # permute is passed in as a block. For example:
 #
 #   >> perms(1) { [1,2,3,4] }
-#   => [[1], [2], [3], [4]] 
+#   => [[1], [2], [3], [4]]
 #   >> perms(2) { [1,2,3,4] }
 #   => [[1, 1], [1, 2], [1, 3], [1, 4], [2, 1], [2, 2], [2, 3], [2, 4],
 #       [3, 1], [3, 2], [3, 3], [3, 4], [4, 1], [4, 2], [4, 3], [4, 4]]
 #
 # The block also gets passed a parameter: the depth of the recursion.
@@ -66,17 +66,17 @@
 def perms(size, n=0, stack=[], &block)
   ps = yield(n)
   results = []
   if n >= size
     results << stack
-  else  
+  else
     ps.each do |p|
       results += perms(size, n+1, stack + [p], &block)
     end
   end
   results
 end
-  
+
 
 if $0 == __FILE__
   puts "-------------- foldl ---"
   p [:sum, [1,1,1].foldl(:+)]
   p ["[[1,2],[3]].foldl(:+)", [[1,2],[3]].foldl(:+)]