Class: ValueSemantics::Attribute

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name:, has_default:, default_value:, validator:, coercer:) ⇒ Attribute

Returns a new instance of Attribute.



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# File 'lib/value_semantics.rb', line 80

def initialize(name:, has_default:, default_value:, validator:, coercer:)
  @name = name.to_sym
  @has_default = has_default
  @default_value = default_value
  @validator = validator
  @coercer = coercer
  freeze
end

Instance Attribute Details

#coercer ⇒ Object (readonly)

Returns the value of attribute coercer.



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# File 'lib/value_semantics.rb', line 78

def coercer
  @coercer
end

#default_value ⇒ Object (readonly)

Returns the value of attribute default_value.



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# File 'lib/value_semantics.rb', line 78

def default_value
  @default_value
end

#has_default ⇒ Object (readonly)

Returns the value of attribute has_default.



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# File 'lib/value_semantics.rb', line 78

def has_default
  @has_default
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/value_semantics.rb', line 78

def name
  @name
end

Instance Method Details

#determine_from!(attr_hash, value_object) ⇒ Object 



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# File 'lib/value_semantics.rb', line 89

def determine_from!(attr_hash, value_object)
  raw_value = attr_hash.fetch(name) do
    if has_default
      default_value
    else
      raise ArgumentError, "Value missing for attribute '#{name}'"
    end
  end

  coerced_value = value_object.instance_exec(raw_value, &coercer)

  if validate?(coerced_value)
    [name, coerced_value]
  else
    raise ArgumentError, "Value for attribute '#{name}' is not valid: #{coerced_value.inspect}"
  end
end

#instance_variable ⇒ Object 



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# File 'lib/value_semantics.rb', line 119

def instance_variable
  '@' + name.to_s.chomp('!').chomp('?')
end

#validate?(value) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/value_semantics.rb', line 115

def validate?(value)
  !!(@validator === value)
end