Class: Rubulator

Inherits:
Object
  • Object
show all
Defined in:
lib/rubulator.rb,
lib/rubulator/version.rb

Defined Under Namespace

Classes: CalculationError, Variable

Constant Summary collapse

VERSION = 
'0.1.0'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Rubulator

Returns a new instance of Rubulator.



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# File 'lib/rubulator.rb', line 28

def initialize
  @variables = {}

  result.store(0.0)
end

Instance Attribute Details

#variables ⇒ Object

Returns the value of attribute variables.



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# File 'lib/rubulator.rb', line 26

def variables
  @variables
end

Class Method Details

.calculate(expression) ⇒ Object 



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# File 'lib/rubulator.rb', line 34

def self.calculate(expression)
  Rubulator.new.calculate(expression)
end

Instance Method Details

#calculate(expression) ⇒ Object 



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# File 'lib/rubulator.rb', line 42

def calculate(expression)
  return unless expression && expression != ''

  operands = expression.sub(/^\s+/, '').sub(/\s+$/, '').split(/\s+/)
  result.store(consume(nil, 'initial', operands).to_f)

  unless operands.empty?
    raise CalculationError, "Operands #{operands.inspect} left over in expression '#{expression}'"
  end

  result.to_f
end

#constants ⇒ Object 



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# File 'lib/rubulator.rb', line 63

def constants
  MATH_CONSTANTS.keys.map(&:to_s)
end

#functions ⇒ Object 



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# File 'lib/rubulator.rb', line 59

def functions
  MATH_FUNCTIONS
end

#operators ⇒ Object 



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# File 'lib/rubulator.rb', line 55

def operators
  ['='] + OPERATORS
end

#result ⇒ Object 



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# File 'lib/rubulator.rb', line 38

def result
  @variables[RESULT_VARIABLE] ||= Variable.new(RESULT_VARIABLE)
end

#variable_names ⇒ Object 



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# File 'lib/rubulator.rb', line 67

def variable_names
  variables.keys.map { |v| VARIABLE_PREFIX + v }
end