Class: SafeArray

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

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ SafeArray

Returns a new instance of SafeArray.



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# File 'lib/universum/safe_array.rb', line 33

def initialize
  ## todo/check: if array works if value is a (nested/multi-dimensional) array
  @ary  = []
end

Class Method Details

.build_class(klass_value) ⇒ Object

e.g.

Array.of( Address ), Array.of( Integer), etc.



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# File 'lib/universum/safe_array.rb', line 8

def self.build_class( klass_value )
  ## note: care for now only about value type / class

  ## note: keep a class cache
  cache = @@cache ||= {}
  klass = cache[ klass_value ]
  return klass   if klass

  klass = Class.new( SafeArray )
  klass.class_eval( <<RUBY )
    def self.klass_value
      @klass_value ||= #{klass_value}
    end
RUBY
  ## add to cache for later (re)use
  cache[ klass_value ] = klass
  klass
end

.new_zero ⇒ Object 



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# File 'lib/universum/safe_array.rb', line 28

def self.new_zero()  new;  end

.zero ⇒ Object 



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# File 'lib/universum/safe_array.rb', line 29

def self.zero()      @zero ||= new_zero;  end

Instance Method Details

#[](index) ⇒ Object 



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# File 'lib/universum/safe_array.rb', line 42

def [](index)
  item = @ary[ index ]
  if item.nil?
    ## todo/check:
    ##    always return (deep) frozen zero object - why? why not?
    ##     let user change the returned zero object - why? why not?
    if self.class.klass_value.respond_to?( :new_zero )
      ## note: use a new unfrozen copy of the zero object
      ##    changes to the object MUST be possible (new "empty" modifable object expected)
     item = self.class.klass_value.new_zero
   else  # assume value semantics e.g. Integer, Bool, etc. zero values gets replaced
     ## puts "use value semantics"
     item = self.class.klass_value.zero
   end
  end
  item
end

#[]=(index, value) ⇒ Object 



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# File 'lib/universum/safe_array.rb', line 38

def []=(index, value)
  @ary[index] = value
end

#length ⇒ Object 



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# File 'lib/universum/safe_array.rb', line 68

def length() size; end

#push(item) ⇒ Object 



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# File 'lib/universum/safe_array.rb', line 60

def push( item )
  ## todo/fix: check if item.is_a? @type
  ##   note: Address might be a String too (Address | String)
  ##     store Address always as String!!! - why? why not?
  @ary.push( item )
end

#size ⇒ Object 



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# File 'lib/universum/safe_array.rb', line 67

def size() @ary.size; end