Class: Relaxo::QueryServer::Reducer

Inherits:
Loader
  • Object
show all
Defined in:
lib/relaxo/query_server/reducer.rb

Overview

Implements the ‘reduce` and `rereduce` functions along with all associated state.

Constant Summary

Constants inherited from Loader

Loader::DEFAULT

Instance Method Summary collapse

Methods inherited from Loader

#add_libraries, #load, #load_default

Constructor Details

#initialize(context) ⇒ Reducer

Create a reducer attached to the given context.



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# File 'lib/relaxo/query_server/reducer.rb', line 41

def initialize(context)
	super()
	
	@context = context
end

Instance Method Details

#reduce(functions, items) ⇒ Object

Apply the reduce function to a given list of items. Functions are typically in the form of:

functions = [lambda{|keys,values,rereduce| ...}]

such that:

items = [[key1, value1], [key2, value2], [key3, value3]]
functions.map{|function| function.call(all keys, all values, false)}

Parameters:

  • functions (Array) —

    An array of functions to apply.

  • items (Array) —

    A composite list of items.



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# File 'lib/relaxo/query_server/reducer.rb', line 58

def reduce(functions, items)
	load_default
	
	functions = functions.collect do |function_text|
		@context.parse_function(function_text, binding)
	end
	
	keys, values = [], []
	
	items.each do |value|
		keys << value[0]
		values << value[1]
	end
	
	result = functions.map do |function|
		ReducingProcess.new(self, function).run(keys, values, false)
	end
	
	return [true, result]
end

#rereduce(functions, values) ⇒ Object

Apply the rereduce functions to a given list of values.

lambda{|keys,values,rereduce| ...}.call([], values, true)

Parameters:

  • functions (Array) —

    An array of functions to apply, in the form of:

  • values (Array) —

    An array of values to reduce



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# File 'lib/relaxo/query_server/reducer.rb', line 86

def rereduce(functions, values)
	load_default
	
	functions = functions.collect do |function_text|
		@context.parse_function(function_text, binding)
	end
	
	result = functions.map do |function|
		ReducingProcess.new(self, function).run([], values, true)
	end
	
	return [true, result]
end