Class: ArrayScanner

Inherits:
Object
  • Object
show all
Defined in:
lib/array_scanner.rb,
lib/array_scanner/version.rb

Constant Summary collapse

VERSION = 
"0.0.2"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(arr, history_size = 10) ⇒ ArrayScanner

Returns a new instance of ArrayScanner.

Raises:

  • (TypeError) 


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# File 'lib/array_scanner.rb', line 9

def initialize(arr, history_size = 10)
  raise TypeError.new("Argument is not an Array.")      unless arr.is_a?(Array)
  raise TypeError.new("History size is not a Fixnum.")  unless history_size.is_a?(Fixnum)

  @arr = arr
  @position = 0

  @pos_hist = Hist.new(history_size)
  @res_hist = Hist.new(history_size)
end

Instance Attribute Details

#pos_hist ⇒ Object (readonly)

Returns the value of attribute pos_hist.



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# File 'lib/array_scanner.rb', line 5

def pos_hist
  @pos_hist
end

#position ⇒ Object Also known as: pos, pointer

Returns the value of attribute position.



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# File 'lib/array_scanner.rb', line 5

def position
  @position
end

#res_hist ⇒ Object (readonly)

Returns the value of attribute res_hist.



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# File 'lib/array_scanner.rb', line 5

def res_hist
  @res_hist
end

Instance Method Details

#current_element ⇒ Object Also known as: points_at, current 



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# File 'lib/array_scanner.rb', line 34

def current_element
  @arr[@position]
end

#eoa ⇒ Object 



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# File 'lib/array_scanner.rb', line 26

def eoa
  size - 1
end

#eoa? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/array_scanner.rb', line 30

def eoa?
  @position == eoa
end

#find ⇒ Object Also known as: next 



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# File 'lib/array_scanner.rb', line 185

def find
  if block_given?
    rest.find { |e| yield e }
  else
    raise needs_block
  end
end

#forward(fixnum) ⇒ Object 



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# File 'lib/array_scanner.rb', line 77

def forward(fixnum)
  new = @position + fixnum
  self.position = (new > eoa ? eoa : new)
end

#forward_to ⇒ Object 



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# File 'lib/array_scanner.rb', line 82

def forward_to
  if block_given?
    f = rest.find { |x| yield(x) }
    f ? self.position = @arr.index(f) : nil
  else
    raise needs_block
  end
end

#inspect ⇒ Object 



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# File 'lib/array_scanner.rb', line 221

def inspect
  "Pointer at #{@position}/#{eoa}. Current element: #{":" if current.is_a?(Symbol)}#{current}"
end

#last_position ⇒ Object 



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# File 'lib/array_scanner.rb', line 56

def last_position
  @pos_hist.recent
end

#last_positions(n = nil) ⇒ Object 



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# File 'lib/array_scanner.rb', line 60

def last_positions(n = nil)
  n ? @pos_hist.recent(n) : @pos_hist.stack
end

#last_result(valid = false) ⇒ Object 



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# File 'lib/array_scanner.rb', line 69

def last_result(valid = false)
  valid ? @res_hist.stack.find { |x| x } : @res_hist.recent
end

#last_results(n = nil) ⇒ Object 



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# File 'lib/array_scanner.rb', line 73

def last_results(n = nil)
  n ? @res_hist.recent(n) : @res_hist.stack
end

#look_behind(n = nil) ⇒ Object 



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# File 'lib/array_scanner.rb', line 171

def look_behind(n = nil)
  n ? scanned.reverse.take(n) : scanned.last
end

#look_behind_until ⇒ Object 



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# File 'lib/array_scanner.rb', line 175

def look_behind_until
  if block_given?
    rev = scanned.reverse
    i = rev.index { |el| yield(el) }
    i ? rev[0...i] : []
  else
    raise needs_block
  end
end

#needs_block ⇒ Object 



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

def needs_block
  ArgumentError.new("Method needs block.")
end

#peek(n = nil) ⇒ Object 



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# File 'lib/array_scanner.rb', line 158

def peek(n = nil)
  n ? rest.take(n) : rest.first
end

#peek_until ⇒ Object 



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# File 'lib/array_scanner.rb', line 162

def peek_until
  if block_given?
    i = rest.index { |el| yield(el) }
    i ? rest[0...i] : []
  else
    raise needs_block
  end
end

#previous ⇒ Object 



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# File 'lib/array_scanner.rb', line 195

def previous
  if block_given?
    scanned.reverse.find { |e| yield e }
  else
    raise needs_block
  end
end

#reset ⇒ Object 



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# File 'lib/array_scanner.rb', line 105

def reset
  self.position = 0
end

#rest ⇒ Object 



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# File 'lib/array_scanner.rb', line 123

def rest
  @arr[@position..-1]
end

#rest_size ⇒ Object 



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# File 'lib/array_scanner.rb', line 127

def rest_size
  size - @position
end

#rewind(fixnum) ⇒ Object 



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# File 'lib/array_scanner.rb', line 91

def rewind(fixnum)
  new = @position - fixnum
  self.position = (new < 0 ? 0 : new)
end

#rewind_to ⇒ Object 



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# File 'lib/array_scanner.rb', line 96

def rewind_to
  if block_given?
    b = scanned.find { |x| yield(x) }
    b ? self.position = @arr.index(b) : nil
  else
    raise needs_block
  end
end

#rr(obj) ⇒ Object 



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# File 'lib/array_scanner.rb', line 203

def rr(obj)
  # means return result
  @res_hist.push(obj)
  obj
end

#scan(forward = true) ⇒ Object 



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# File 'lib/array_scanner.rb', line 131

def scan(forward = true)
  res = @arr[@position]

  if block_given? and not yield(res)
    rr(false)
  else
    forward(1) if forward &! eoa?
    rr(res)
  end
end

#scan_until(include_true_element = false) ⇒ Object 



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# File 'lib/array_scanner.rb', line 142

def scan_until(include_true_element = false)
  if block_given?
    if e = rest.find { |el| yield(el) }
      i  = @arr.index(e)
      i += 1 if include_true_element

      self.position = (i > eoa ? eoa : i)
      rr(@arr[last_position...i])
    else
      rr(false)
    end
  else
    raise needs_block
  end
end

#scanned ⇒ Object 



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

def scanned
  @arr[0...@position]
end

#scanned_size ⇒ Object 



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

def scanned_size
  @position
end

#size ⇒ Object Also known as: length 



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# File 'lib/array_scanner.rb', line 20

def size
  @arr.size
end

#surroundings ⇒ Object 



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# File 'lib/array_scanner.rb', line 52

def surroundings
  [scanned.last, rest[1]]
end

#terminate ⇒ Object Also known as: clear 



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# File 'lib/array_scanner.rb', line 109

def terminate
  self.position = eoa
end

#to_a ⇒ Object 



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

def to_a
  @arr
end

#to_s ⇒ Object 



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# File 'lib/array_scanner.rb', line 217

def to_s
  @arr.to_s
end

#unscan(steps = 1) ⇒ Object 



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# File 'lib/array_scanner.rb', line 64

def unscan(steps = 1)
  return nil if last_positions.empty?
  self.position = last_positions[steps - 1] || last_positions.last
end