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Contents
require 'epitools/basetypes'
class Array
alias_method :"original_*_for_cartesian_*", :*
def *(other)
case other
when Integer
send(:"original_*_for_cartesian_*", other)
when Array
# cross-product
result = []
(0...self.size).each do |a|
(0...other.size).each do |b|
result << [self[a], other[b]]
end
end
result
end
end
def **(exponent)
([self] * exponent).foldl(:*)
end
end
def perms(total, n=0, stack=[], &block)
ps = yield(n)
results = []
if n >= total
results << stack
else
ps.each do |p|
results += perms(total, 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(:+)]
p [[0,1],[0,1]].foldl(:*)
puts "-------------- cartesian product ---"
p ["[0,1]*[2,3]",[0,1]*[2,3]]
puts "-------------- cartesian exponent ---"
p [0,1]**3
end
Version data entries
12 entries across 12 versions & 1 rubygems