Class: Unitwise::Expression::Composer

Inherits:
Object
  • Object
show all
Defined in:
lib/unitwise/expression/composer.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(terms) ⇒ Composer

Returns a new instance of Composer.



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# File 'lib/unitwise/expression/composer.rb', line 5

def initialize(terms)
  @terms = terms
end

Instance Attribute Details

#terms ⇒ Object (readonly)

Returns the value of attribute terms.



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# File 'lib/unitwise/expression/composer.rb', line 4

def terms
  @terms
end

Instance Method Details

#denominator ⇒ Object 



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# File 'lib/unitwise/expression/composer.rb', line 21

def denominator
  @denominator ||= set.select{|k,v| v < 0}.map do |k,v|
    "#{k[:f] if k[:f] != 1}#{k[:p]}#{k[:a]}#{-v if v != -1}"
  end.select{|t| !t.empty?}.join('.')
end

#expression ⇒ Object 



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# File 'lib/unitwise/expression/composer.rb', line 27

def expression
  @expression = []
  @expression << (numerator.empty? ? '1' : numerator)
  (@expression << denominator) unless denominator.empty?
  @expression.join('/')
end

#numerator ⇒ Object 



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# File 'lib/unitwise/expression/composer.rb', line 15

def numerator
  @numerator ||= set.select{|k,v| v > 0}.map do |k,v|
    "#{k[:f] if k[:f] != 1}#{k[:p]}#{k[:a]}#{v if v != 1}"
  end.select{|t| !t.empty?}.join('.')
end

#set ⇒ Object 



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# File 'lib/unitwise/expression/composer.rb', line 9

def set
  @set ||= terms.reduce(SignedMultiset.new) do |s, t|
    s.increment({:f => t.factor, :p => t.prefix, :a => t.atom}, t.exponent); s
  end
end