Class: Unitwise::Atom

Inherits:
Base
  • Object
show all
Includes:
Compatible
Defined in:
lib/unitwise/atom.rb

Overview

Atoms are the most basic elements in Unitwise. They are named coded and scaled units without prefixes, multipliers, exponents, etc. Examples are ‘meter’, ‘hour’, ‘pound force’.

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Compatible

#<=>, #compatible_with?, #composition, #composition_string, included, #initialize

Methods inherited from Base

all, find, #names=, #slugs, #to_s

Class Method Details

.data ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Array of hashes representing atom properties.



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# File 'lib/unitwise/atom.rb', line 12

def data
  @data ||= data_files.map { |file| YAML.load(File.open file) }.flatten
end

.data_files ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Data files containing atom data



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# File 'lib/unitwise/atom.rb', line 18

def data_files
  %w(base_unit derived_unit).map { |type| Unitwise.data_file type }
end

Instance Method Details

#arbitrary ⇒ true, false Also known as: arbitrary?

Determine if a unit is arbitrary. Arbitrary atoms are not of any specific dimension and have no general meaning, therefore cannot be compared with any other unit.

Returns:

  • (true, false) 


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# File 'lib/unitwise/atom.rb', line 62

def arbitrary
  !!@arbitrary
end

#base? ⇒ true, false

Determine if an atom is base level. All atoms that are not base are defined directly or indirectly in reference to a base atom.

Returns:

  • (true, false) 


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# File 'lib/unitwise/atom.rb', line 27

def base?
  !!(@dim && !scale)
end

#depth ⇒ Integer

Determine how far away a unit is from a base unit.

Returns:

  • (Integer) 


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# File 'lib/unitwise/atom.rb', line 70

def depth
  base? ? 0 : scale.depth + 1
end

#derived? ⇒ true, false

Determine if an atom is derived. Derived atoms are defined with respect to other atoms.

Returns:

  • (true, false) 


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# File 'lib/unitwise/atom.rb', line 35

def derived?
  !base?
end

#dim ⇒ String

A representation of an atoms composition. Used to determine if two different atoms are compatible.

Returns:

  • (String) 


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# File 'lib/unitwise/atom.rb', line 86

def dim
  terminal? ? @dim || property : composition_string
end

#magnitude(scalar = scalar()) ⇒ Object 



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# File 'lib/unitwise/atom.rb', line 109

def magnitude(scalar = scalar())
  special? ? scale.magnitude(scalar) : BigDecimal('1')
end

#metric ⇒ true, false Also known as: metric?

Determine if an atom is metric. Metric atoms can be combined with metric prefixes.

Returns:

  • (true, false) 


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# File 'lib/unitwise/atom.rb', line 43

def metric
  base? ? true : !!@metric
end

#root_terms ⇒ Array

An atom may have a complex scale with several base atoms at various depths. This method returns all of this atoms base level terms.

Returns:

  • (Array) —

    An array containing base Unitwise::Term



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# File 'lib/unitwise/atom.rb', line 116

def root_terms
  base? ? [Term.new(:atom_code => primary_code)] : scale.root_terms
end

#scalar(magnitude = 1) ⇒ Numeric

Get a numeric value that can be used to with other atoms to compare with or operate on. Base units have a scalar of 1.

Returns:

  • (Numeric) 


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# File 'lib/unitwise/atom.rb', line 105

def scalar(magnitude = 1)
  base? ? BigDecimal(magnitude.to_s) : scale.scalar(magnitude)
end

#scale=(attrs) ⇒ Unitwise::Functional, Unitwise::Scale

Set the atom’s scale. It can be set as a Scale or a Functional

Returns:



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# File 'lib/unitwise/atom.rb', line 93

def scale=(attrs)
  @scale = if attrs[:function_code]
    Functional.new(attrs[:value], attrs[:unit_code], attrs[:function_code])
  else
    Scale.new(attrs[:value], attrs[:unit_code])
  end
end

#special ⇒ true, false Also known as: special?

Determine if a unit is special. Special atoms are not defined on a traditional ratio scale.

Returns:

  • (true, false) 


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# File 'lib/unitwise/atom.rb', line 52

def special
  !!@special
end

#terminal? ⇒ true, false

Determine if this is the last atom in the scale chain

Returns:

  • (true, false) 


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# File 'lib/unitwise/atom.rb', line 78

def terminal?
  depth <= 3
end