Sha256: db847847f6eeaab4eb127d7d2a1363847c0dad0f293615f25f927bc627d82f50
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Size: 966 Bytes
Versions: 5
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Stored size: 966 Bytes
Contents
module Alf
module Engine
#
# Filters tuples from `left` that match or do not match tuples from `right`.
#
class Semi::Hash < Cog
# @return [Enumerable] The left operand
attr_reader :left
# @return [Enumerable] The right operand
attr_reader :right
# @return [Boolean] Match (true) or not match (false)?
attr_reader :predicate
# Creates a Semi::Hash instance
def initialize(left, right, predicate)
@left = left
@right = right
@predicate = predicate
end
# (see Cog#each)
def each
index = nil
left.each do |left_tuple|
index ||= Materialize::Hash.new(right, lambda{|t|
AttrList.new(left_tuple.keys & t.keys)
}).prepare
if index[left_tuple, true].empty? != predicate
yield left_tuple
end
end
end
end # class Semi::Hash
end # module Engine
end # module Alf
Version data entries
5 entries across 5 versions & 1 rubygems