Sha256: 1b2b187aba8998978d93d1d31f956403f8c1637e89c4f24c2ca63bb2d2c6970c
Contents?: true
Size: 671 Bytes
Versions: 13
Compression:
Stored size: 671 Bytes
Contents
module Alf
class Aggregator
#
# Defines a `count()` aggregation operator.
#
# Example:
#
# # direct ruby usage
# Alf::Aggregator.count.aggregate(...)
#
# # lispy
# (summarize :supplies, [:sid], :num_orders => count)
#
class Count < Aggregator
# Returns 0 as least value.
#
# @see Aggregator::InstanceMethods#least
def least()
0
end
# Aggregates on a tuple occurence through `memo + 1`
#
# @see Aggregator::InstanceMethods#happens
def happens(memo, tuple)
memo + 1
end
end # class Count
end # class Aggregator
end # module Alf
Version data entries
13 entries across 13 versions & 2 rubygems