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Size: 1012 Bytes
Versions: 5
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Stored size: 1012 Bytes
Contents
module Alf
module Engine
#
# Provides hash-based join.
#
class Join::Hash
include Join
include Cog
# @return [Enumerable] The left operand
attr_reader :left
# @return [Enumerable] The right operand
attr_reader :right
# Creates a Join::Hash instance
def initialize(left, right, expr = nil, compiler = nil)
super(expr, compiler)
@left = left
@right = right
end
# Returns left and right operands in an array
def operands
[ left, right ]
end
# (see Cog#each)
def _each(&block)
index = nil
left.each do |left_tuple|
index ||= Materialize::Hash.new(right, lambda{|t|
AttrList.new(left_tuple.keys & t.keys)
}, false, expr).prepare
index[left_tuple, true].each do |right_tuple|
yield left_tuple.merge(right_tuple)
end
end
end
end # class Hash
end # module Engine
end # module Alf
Version data entries
5 entries across 5 versions & 1 rubygems