Error: can't use variable name 'some_name' inside assignment to variable 'some_name'

Help & Support
1

Following code not work on crystal.

def keys
    keys = [] of String

    _keys = proc do |arr, node|
      next if node.nil?

      _keys.call(arr, node.left)
      arr << node.key unless node.key == ''
      _keys.call(arr, node.right)
    end

    _keys.call(keys, @root)

    keys
  end

 80 | _keys.call(arr, node.left)
      ^
Error: can't use variable name '_keys' inside assignment to variable '_keys'

Bascially, it just equal to:

def keys
    keys = [] of String

    _keys(keys, root)

    keys
  end

  def _keys(arr, node)
    return if node.nil?

    _keys(arr, node.left)
    arr << node.key unless node.key.blank?
    _keys(arr, node.right)
  end

How to fix that?

Thank you.

2
1 Like
3

It works!

  def keys
    keys = [] of String
    _keys = uninitialized (Array(String), Node?) ->

    _keys = ->(arr : Array(String), node : Node?) do
      return if node.nil?

      _keys.call(arr, node.left)
      arr << node.key unless node.key == ""
      _keys.call(arr, node.right)
    end

    _keys.call(keys, @root)

    keys
  end

Although, i have to use return if node.nil? instead next if node.nil?(in ruby), return return to the _keys.call(...), not the method keys, this is expected, right?

Then, how to return to the keys method?

5

No way

1 Like