Class: Async::Service::Environment::Evaluator

Inherits:
Object
  • Object
show all
Defined in:
lib/async/service/environment.rb

Overview

An evaluator is lazy read-only view of an environment. It memoizes all method calls.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Evaluator

Initialize a new evaluator.



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# File 'lib/async/service/environment.rb', line 171

def initialize
	@cache = {}
end

Class Method Details

.wrap(environment) ⇒ Object

Create an evaluator wrapper for an environment.



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# File 'lib/async/service/environment.rb', line 140

def self.wrap(environment)
	evaluator = ::Class.new(self)
	
	facet = ::Module.new
	environment.included(facet)
	
	evaluator.include(facet)
	
	keys = []
	
	# Memoize all instance methods:
	facet.instance_methods.each do |name|
		instance_method = facet.instance_method(name)
		
		# Only memoize methods with no arguments:
		if instance_method.arity == 0
			keys << name
			
			evaluator.define_method(name) do
				@cache[name] ||= super()
			end
		end
	end
	
	# This lists all zero-argument methods:
	evaluator.define_method(:keys){keys}
	
	return evaluator.new
end

Instance Method Details

#[](key) ⇒ Object

Get value for a given key.



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# File 'lib/async/service/environment.rb', line 202

def [](key)
	if self.key?(key)
		self.__send__(key)
	end
end

#inspect ⇒ Object

Inspect representation of the evaluator.



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# File 'lib/async/service/environment.rb', line 177

def inspect
	"#<#{Evaluator} #{self.keys}>"
end

#key?(key) ⇒ Boolean

Check if a key is available.

Returns:

  • (Boolean) 


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# File 'lib/async/service/environment.rb', line 211

def key?(key)
	self.keys.include?(key)
end

#to_h ⇒ Object

Convert the evaluator to a hash.



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# File 'lib/async/service/environment.rb', line 183

def to_h
	# Ensure all keys are evaluated:
	self.keys.each do |name|
		self.__send__(name)
	end
	
	return @cache
end

#to_json ⇒ Object

Convert the evaluator to JSON.



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# File 'lib/async/service/environment.rb', line 195

def to_json(...)
	self.to_h.to_json(...)
end