Class: StringNumber

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

Constant Summary collapse

SYMBOLS = 
Hash[('A'..'Z').each_with_index.map{|s,i| [s,i+1]

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value) ⇒ StringNumber

Returns a new instance of StringNumber.

Raises:

  • (ArgumentError) 


4
5
6
7
 
# File 'lib/string_number.rb', line 4

def initialize(value)
  raise ArgumentError, "Invalid value for #{self.class.name} (#{value})" unless self.class.valid(value)
  @value = value.upcase
end

Class Method Details

.[](number) ⇒ Object 



40
41
42
43
44
45
46
47
48
 
# File 'lib/string_number.rb', line 40

def self.[](number)
  return self.new(SYMBOLS.keys[number-1]) if number <= SYMBOLS.count

  quotient = number / base
  reminder = number % base
  quotient -= 1 if reminder == 0
  recursive = self[quotient].to_s if quotient > 0
  self.new((recursive || '') + SYMBOLS.keys[reminder-1])
end

.base ⇒ Object 



50
51
52
 
# File 'lib/string_number.rb', line 50

def self.base
  SYMBOLS.count
end

.valid(string) ⇒ Object 



54
55
56
57
 
# File 'lib/string_number.rb', line 54

def self.valid(string)
  return false unless string.is_a? String
  string.match(/[A-Z]*/i).to_s == string
end

Instance Method Details

#+(value) ⇒ Object 



9
10
11
 
# File 'lib/string_number.rb', line 9

def +(value)
  self.class[to_i + number_of(value)]
end

#-(value) ⇒ Object

Raises:

  • (StandardError) 


13
14
15
16
17
18
 
# File 'lib/string_number.rb', line 13

def -(value)
  number = number_of(value)
  result = to_i - number
  raise StandardError, "Cant substract from #{number} to #{to_s}" if result < 1
  self.class[result]
end

#==(other) ⇒ Object 



25
26
27
28
 
# File 'lib/string_number.rb', line 25

def ==(other)
  return false unless other.is_a? self.class
  to_s == other.to_s
end

#eql?(other) ⇒ Boolean

Returns:

  • (Boolean) 


20
21
22
23
 
# File 'lib/string_number.rb', line 20

def eql?(other)
  return false unless other.is_a? self.class
  to_s.eql?(other.to_s)
end

#to_i ⇒ Object 



34
35
36
37
38
 
# File 'lib/string_number.rb', line 34

def to_i
  segments = @value.reverse.split('')
  units = segments.each_with_index.map{ |s,i| SYMBOLS[s] * self.class.base**i }
  units.inject(:+)
end

#to_s ⇒ Object 



30
31
32
 
# File 'lib/string_number.rb', line 30

def to_s
  @value
end