Question

我希望我的代码执行以下操作：

def debug (message)
  puts message.rjust(message.length + (stack_trace-1 * 2)) # -1 for the call to debug
end

def a
  debug "in a"
  b
  debug "end a"
end

def b
  debug "in b"
  c
  debug "end b"
end

def c
  debug "in c"
  meaningful_work
  debug "end c"
end

输出：

in a
  in b
    in c
    end c
  end b
end a

我以前在PHP中做过这样的事情，比如：

function echon($string){
  $nest_level = count(debug_backtrace()) - 1; // minus one to ignore the call to *this* function
  echo str_repeat("  ", $nest_level) . $string . "\n";
}

就我的google-fu而言，没有Ruby等同于debug_backtrace。我不想修改我正在工作的代码库中的所有众多方法的调用以传递回溯 - 这是不必要的繁琐且难以还原。

我可以使用一些全局跟踪吗？

Answer 1

只需将Kernel#caller与.length一起使用即可。 caller(0).length将为您提供当前的堆栈深度。

示例：

irb(main):001:0> caller(0)
=> ["(irb):1:in `irb_binding'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/workspace.rb:86:in `eval'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/workspace.rb:86:in `evaluate'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/context.rb:380:in `evaluate'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:492:in `block (2 levels) in eval_input'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:624:in `signal_status'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:489:in `block in eval_input'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:247:in `block (2 levels) in each_top_level_statement'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:233:in `loop'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:233:in `block in each_top_level_statement'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:232:in `catch'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:232:in `each_top_level_statement'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:488:in `eval_input'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:397:in `block in start'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:396:in `catch'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:396:in `start'", "/usr/bin/irb:12:in `<main>'"]
irb(main):002:0> caller(0).length
=> 17

Answer 2

这是实现@nneonneo优秀建议的一种方法。

<强>代码

INDENT = 2

def debug(msg=nil)
  @prev_arr_size ||= 1
  @arrived ||= false
  arr = caller(1)
  indent = ' '*(arr.size-2)*INDENT
  if msg
    puts indent + msg
    return
  end 
  meth, call_meth = method_str(arr[0]), method_str(arr[1])
  entering = (@prev_arr_size==arr.size) ? !@arrived : @prev_arr_size < arr.size
  msg1, msg2 = entering ? ["in ", "called from "] : ["end", "returning to"]
  puts indent  + "%s %s, %s %s" % [msg1, meth, msg2, call_meth]
  @prev_arr_size = arr.size
  @arrived = !@arrived
end

def method_str(str)
  file, _, meth = str.partition(/:.*?in\s+/)
  "#{meth[1..-2]} (#{file})"
end

示例

def a debug # frivolous work b debug end def b debug c x = 5 debug "It seems that x is now #{x}" # more frivolous work c debug end def c debug # meaningful_work debug end a #=> in a (t.rb), called from <main> (t.rb) # in b (t.rb), called from a (t.rb) # in c (t.rb), called from b (t.rb) # end c (t.rb), returning to b (t.rb) # It seems that x is now 5 # in c (t.rb), called from b (t.rb) # end c (t.rb), returning to b (t.rb) # end b (t.rb), returning to a (t.rb) # end a (t.rb), returning to <main> (t.rb)

为了进行调试，如何跟踪堆栈跟踪高度？

2 个答案: