Class: Stream::CollectionStream

Inherits:
BasicStream show all
Defined in:
lib/stream.rb

Overview

A CollectionStream can be used as an external iterator for each interger-indexed collection. The state of the iterator is stored in instance variable @pos.

A CollectionStream for an array is created by the method Array#create_stream.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(seq) ⇒ CollectionStream

Creates a new CollectionStream for the indexable sequence seq.

Parameters:

  • seq (Array) —

    an integer-indexed collection



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# File 'lib/stream.rb', line 204

def initialize(seq)
  @seq = seq
  set_to_begin
end

Instance Attribute Details

#pos ⇒ Object (readonly)

Returns the value of attribute pos.



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# File 'lib/stream.rb', line 200

def pos
  @pos
end

Instance Method Details

#at_beginning? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/stream.rb', line 213

def at_beginning?
  @pos < 0
end

#at_end? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/stream.rb', line 209

def at_end?
  @pos + 1 >= @seq.size
end

#basic_backward ⇒ Object 



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# File 'lib/stream.rb', line 232

def basic_backward
  r = @seq[@pos]
  @pos -= 1; r
end

#basic_forward ⇒ Object 



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# File 'lib/stream.rb', line 227

def basic_forward
  @pos += 1
  @seq[@pos]
end

#set_to_begin ⇒ Object

positioning



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# File 'lib/stream.rb', line 219

def set_to_begin
  @pos = -1
end

#set_to_end ⇒ Object 



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# File 'lib/stream.rb', line 223

def set_to_end
  @pos = @seq.size - 1
end