Class: Rigor::Trinary

Inherits:
Object
  • Object
show all
Defined in:
lib/rigor/trinary.rb,
sig/rigor/trinary.rbs

Overview

Three-valued logic value object shared by capability queries, relational queries, and any analyzer surface that distinguishes "proven yes", "proven no", and "cannot prove either".

See docs/type-specification/relations-and-certainty.md for semantics and docs/internal-spec/internal-type-api.md for the contract.

Constant Summary collapse

VALUES =

Returns:

%i[yes no maybe].freeze
YES =

Returns:


      
        
NO =
          

  

    

  





  

Returns:





        

        

      
        
MAYBE =
          

  

    

  





  

Returns:





        

        

      
    

  




  
Class Attribute Summary collapse

  

  
Instance Attribute Summary collapse

  




  
    

      Class Method Summary
      collapse
    


    
    
  
    

      Instance Method Summary
      collapse
    


    
    
  



  
Constructor Details

  
    

  

  
    #initialize(value)  ⇒ Trinary 
  

  

  


  

    
Returns a new instance of Trinary.


  





  
Parameters:




Raises:


    
  
    
  • 
      
      
        (ArgumentError)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rigor/trinary.rb', line 33

def initialize(value)
  raise ArgumentError, "unknown trinary value: #{value.inspect}" unless VALUES.include?(value)

  @value = value
end

    		
  





  



  

    
Class Attribute Details

    
      
      
      

  

  
    .maybe  ⇒ Trinary  (readonly)
  

  

  


  

    
Returns the value of attribute maybe.


  





  

Returns:





  

    
      


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# File 'lib/rigor/trinary.rb', line 18

def maybe
  @maybe
end

    		
  





    
      
      
      

  

  
    .no  ⇒ Trinary  (readonly)
  

  

  


  

    
Returns the value of attribute no.


  





  

Returns:





  

    
      


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# File 'lib/rigor/trinary.rb', line 18

def no
  @no
end

    		
  





    
      
      
      

  

  
    .yes  ⇒ Trinary  (readonly)
  

  

  


  

    
Returns the value of attribute yes.


  





  

Returns:





  

    
      


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# File 'lib/rigor/trinary.rb', line 18

def yes
  @yes
end

    		
  





    
  


  

    
Instance Attribute Details

    
      
      
      

  

  
    #value  ⇒ value  (readonly)
  

  

  


  

    
Returns the value of attribute value.


  





  

Returns:





  

    
      


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# File 'lib/rigor/trinary.rb', line 31

def value
  @value
end

    		
  





    
  



  

    
Class Method Details


    
      

  

  
    .from_symbol(symbol)  ⇒ Trinary 
  

  

  


  

    

  





  
Parameters:


    
  
    
  • 
      
        symbol
      
      
        (Symbol)
      
      
      
    
    • 
  




Returns:





  

    
      


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# File 'lib/rigor/trinary.rb', line 20

def from_symbol(symbol)
  case symbol
  when :yes then yes
  when :no then no
  when :maybe then maybe
  else
    raise ArgumentError, "unknown trinary value: #{symbol.inspect}"
  end
end

    		
  





    
  


  

    
Instance Method Details


    
      

  

  
    #==(other)  ⇒ Boolean 
  

  
    Also known as:
    eql?
    
  

  


  

    

  





  
Parameters:


    
  
    
  • 
      
        other
      
      
        (Object)
      
      
      
    
    • 
  




Returns:


    
  
    
  • 
      
      
        (Boolean)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rigor/trinary.rb', line 77

def ==(other)
  other.is_a?(Trinary) && value == other.value
end

    		
  





    
      

  

  
    #and(other)  ⇒ Trinary 
  

  

  


  

    
Conjunction. yes & yes = yes, no with anything = no, otherwise maybe.


  





  
Parameters:




Returns:





  

    
      


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# File 'lib/rigor/trinary.rb', line 60

def and(other)
  coerced = coerce(other)
  return self.class.no if no? || coerced.no?
  return self.class.yes if yes? && coerced.yes?

  self.class.maybe
end

    		
  





    
      

  

  
    #hash  ⇒ Integer 
  

  

  


  

    

  





  

Returns:


    
  
    
  • 
      
      
        (Integer)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rigor/trinary.rb', line 82

def hash
  value.hash
end

    		
  





    
      

  

  
    #inspect  ⇒ String 
  

  

  


  

    

  





  

Returns:


    
  
    
  • 
      
      
        (String)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rigor/trinary.rb', line 90

def inspect
  "#<Rigor::Trinary #{value}>"
end

    		
  





    
      

  

  
    #maybe?  ⇒ Boolean 
  

  

  


  

    

  





  

Returns:


    
  
    
  • 
      
      
        (Boolean)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rigor/trinary.rb', line 47

def maybe?
  value == :maybe
end

    		
  





    
      

  

  
    #negate  ⇒ Trinary 
  

  

  


  

    

  





  

Returns:





  

    
      


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# File 'lib/rigor/trinary.rb', line 51

def negate
  case value
  when :yes then self.class.no
  when :no then self.class.yes
  else self.class.maybe
  end
end

    		
  





    
      

  

  
    #no?  ⇒ Boolean 
  

  

  


  

    

  





  

Returns:


    
  
    
  • 
      
      
        (Boolean)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rigor/trinary.rb', line 43

def no?
  value == :no
end

    		
  





    
      

  

  
    #or(other)  ⇒ Trinary 
  

  

  


  

    
Disjunction. yes with anything = yes, no & no = no, otherwise maybe.


  





  
Parameters:




Returns:





  

    
      


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# File 'lib/rigor/trinary.rb', line 69

def or(other)
  coerced = coerce(other)
  return self.class.yes if yes? || coerced.yes?
  return self.class.no if no? && coerced.no?

  self.class.maybe
end

    		
  





    
      

  

  
    #to_s  ⇒ String 
  

  

  


  

    

  





  

Returns:


    
  
    
  • 
      
      
        (String)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rigor/trinary.rb', line 86

def to_s
  value.to_s
end

    		
  





    
      

  

  
    #yes?  ⇒ Boolean 
  

  

  


  

    

  





  

Returns:


    
  
    
  • 
      
      
        (Boolean)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rigor/trinary.rb', line 39

def yes?
  value == :yes
end