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module Picky
module Query
# Calculates scores/weights for combinations.
#
# Example:
# Someone searches for peter fish.
# Picky might match this to categories as follows:
# [:name, :food]
# and
# [:name, :surname]
#
# This class is concerned with calculating scores
# for the category combinations.
#
# Implement either
# #score_for(combinations)
# or
# #weight_for(category_names) # Subclass this class for this.
#
# And return a weight.
#
class Weights
attr_reader :weights
delegate :empty?,
:to => :weights
# Needs a Hash of
# [:category_name1, :category_name2] => +3
# (some positive or negative weight)
#
def initialize weights = {}
@weights = weights
end
# API.
#
# Get the weight for an array of category names.
#
# Example:
# [:name, :height, :color] returns +3, but
# [:name, :height, :street] returns -1.
#
# Note: Use Array#clustered_uniq_fast to make
# [:a, :a, :b, :a] => [:a, :b, :a]
#
def weight_for category_names
@weights[category_names.clustered_uniq_fast] || 0
end
# API.
#
# Calculates a score for the combinations.
# Implement #weight_for(category_names) if you don't need the
# actual combinations, just the category names.
#
# Note: Cache this if more complicated weighings become necessary.
# Note: Maybe make combinations comparable to Symbols?
#
def score_for combinations
weight_for combinations.map(&:category_name)
end
# A Weights instance is == to another if
# the weights are the same.
#
def == other
@weights == other.weights
end
# Prints out a nice representation of the
# configured weights.
#
def to_s
"#{self.class}(#{@weights})"
end
end
end
end
Version data entries
51 entries across 51 versions & 1 rubygems