def find_captures(fast = @fast)
      return true if fast == @fast && !captures?(fast)

      case fast
      when Capture then fast.captures
      when Array then fast.flat_map(&method(:find_captures)).compact
      when Find then find_captures(fast.token)
      end
    end
def find_captures(fast = @fast)
      return true if fast == @fast && !captures?(fast)

      case fast
      when Capture then fast.captures
      when Array then fast.flat_map(&method(:find_captures)).compact
      when Find then find_captures(fast.token)
      end
    end
Find search captures recursively.

 @return [Array<Object>] of captures from the expression
 @return [true] in case of no captures in the expression
 @see Fast::Capture
 @see Fast::FindFromArgument