Method: Immutable::Headable#fetch

Defined in:
lib/immutable/headable.rb

#fetch(n) ⇒ Object #fetch(n, ifnone) ⇒ Object #fetch(n) {|n| ... } ⇒ Object

Returns the nth element of self. If n is out of range, IndexError returned.

Overloads:

  • #fetch(n) ⇒ Object

    Returns the nth element.

    Parameters:

    • n (Integer, #to_int)

    Returns:

    • (Object) —

      the nth element.

    Raises:

    • (IndexError) —

      if n is out of rage

  • #fetch(n, ifnone) ⇒ Object

    Returns ifnone.

    Parameters:

    • n (Integer, #to_int)

    Returns:

    • ifnone

  • #fetch(n) {|n| ... } ⇒ Object

    Parameters:

    • n (Integer, #to_int)

    Yields:

    • (n)

    Yield Parameters:

    • n (Integer, #to_int)

Raises:

  • (TypeError) 


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# File 'lib/immutable/headable.rb', line 255

def fetch(*args)
  alen = args.length
  n, ifnone = *args
  
  unless (1..2).cover?(alen)
    raise ArgumentError, "wrong number of arguments (#{alen} for 1..2)"
  end

  raise TypeError unless n.respond_to?(:to_int)
  int = n.to_int

  return at(int) if int >= 0 && int < length

  if block_given?
    if alen == 2
      warn "#{__LINE__}:warning: block supersedes default value argument"
    end

    yield n
  else
    if alen == 2
      ifnone
    else
      raise IndexError, "index #{int} outside of list bounds"
    end
  end
end