Class: Theta::Environment

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

Overview

particular level

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(parent = nil) ⇒ Environment

Returns a new instance of Environment.



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# File 'lib/theta/environment.rb', line 8

def initialize(parent = nil)
	@parent = parent
	@table = {}
	if @parent.nil?
		define("#t".to_sym, true)
		define("#f".to_sym, false)
	end
end

Instance Attribute Details

#parent ⇒ Object

Returns the value of attribute parent.



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# File 'lib/theta/environment.rb', line 6

def parent
  @parent
end

Instance Method Details

#define(name, value) ⇒ Object

define an item in the environment



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# File 'lib/theta/environment.rb', line 29

def define(name, value)
	@table[name] = value
end

#find(name) ⇒ Object

find an item in the environment



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# File 'lib/theta/environment.rb', line 18

def find(name)
	if @table.has_key?(name)
		return @table[name]
	elsif @parent.nil?
		return nil
	else
		@parent.find(name)
	end
end