Class: LSystem::RulesEngine

Inherits:
Object
  • Object
show all
Extended by:
Loggability
Defined in:
lib/l_system/rules_engine.rb

Overview

An engine for iterating over successive applications of the L-System’s ruleset to its axiom.

Instance Method Summary collapse

Constructor Details

#initialize(&block) ⇒ RulesEngine

Create a new rules engine for an L-System. If the block is present, it is called with the new instance as self.



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# File 'lib/l_system/rules_engine.rb', line 22

def initialize( &block )
	@variables = Set.new
	@constants = Set.new
	@axiom = nil
	@rules = []

	@rules_as_hash = nil

	self.instance_eval( &block ) if block
end

Instance Method Details

#alphabet ⇒ Object

Return the system’s variables and constants.



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# File 'lib/l_system/rules_engine.rb', line 85

def alphabet
	return @variables | @constants
end

#apply_rules(state) ⇒ Object

Apply the system’s rules to the given state and return the result.



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# File 'lib/l_system/rules_engine.rb', line 122

def apply_rules( state )
	rules_hash = self.rules_as_hash
	return state.each_char.with_object( String.new(encoding: 'utf-8') ) do |char, new_state|
		new_state << rules_hash[ char ]
	end
end

#axiom(new_value = nil) ⇒ Object

Get/set the axiom of the system.



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# File 'lib/l_system/rules_engine.rb', line 91

def axiom( new_value=nil )
	self.axiom = new_value if new_value
	return @axiom
end

#axiom=(new_value) ⇒ Object

Set the axiom of the system.



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# File 'lib/l_system/rules_engine.rb', line 98

def axiom=( new_value )
	@axiom = new_value
end

#constants(*new_values) ⇒ Object

Get/set the system’s constants (the static parts of its alphabet).



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# File 'lib/l_system/rules_engine.rb', line 64

def constants( *new_values )
	self.constants = new_values unless new_values.empty?
	return @constants.dup
end

#constants=(new_values) ⇒ Object

Set the systems constants to new_values.



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# File 'lib/l_system/rules_engine.rb', line 71

def constants=( new_values )
	@rules_as_hash = nil

	new_values = Set.new( new_values, &:to_s )
	unless new_values.disjoint?( self.variables )
		common_char = (new_values & self.variables).to_a.first
		raise ArgumentError, "%p is already included in the variable set" % [ common_char ]
	end

	@constants = new_values
end

#each(&block) ⇒ Object

Yield each successive generation to the given block, or return an Enumerator that will do so if no block is given.



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# File 'lib/l_system/rules_engine.rb', line 132

def each( &block )
	iter = Enumerator.new do |yielder|
		state = new_state = self.axiom.dup

		begin
			yielder.yield( new_state )
			state = new_state
			new_state = self.apply_rules( state )
		end until state == new_state
	end

	return iter unless block
	return iter.each( &block )
end

#rules(*new_values) ⇒ Object

Get/set the system’s rules.



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# File 'lib/l_system/rules_engine.rb', line 104

def rules( *new_values )
	self.rules = new_values unless new_values.empty?
	return @rules
end

#rules=(new_values) ⇒ Object

Set the system’s rules.



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# File 'lib/l_system/rules_engine.rb', line 111

def rules=( new_values )
	@rules_as_hash = nil
	@rules = Array( new_values ).map( &:to_s )
end

#variables(*new_values) ⇒ Object

Get/set the system’s variables (the replaceable parts of its alphabet).



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# File 'lib/l_system/rules_engine.rb', line 43

def variables( *new_values )
	self.variables = new_values unless new_values.empty?
	return @variables.dup
end

#variables=(new_values) ⇒ Object

Set the systems variables to new_values.



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# File 'lib/l_system/rules_engine.rb', line 50

def variables=( new_values )
	@rules_as_hash = nil

	new_values = Set.new( new_values, &:to_s )
	unless new_values.disjoint?( self.constants )
		common_char = (new_values & self.constants).to_a.first
		raise ArgumentError, "%p is already included in the constant set" % [ common_char ]
	end

	@variables = new_values
end