python - Ruby 内联文档

Question

在 IRB 或其他交互式解释器(如 pry)中，如何获取有关对象和方法的内联文档？例如，我可以做到这一点:

[1] pry(main)> x = 'hello world'
=> "hello world"
[2] pry(main)> x.st
x.start_with?  x.strip        x.strip!   
[2] pry(main)> x.st

但现在我想阅读用法/接口(interface)/rdoc 必须说明的关于这些方法及其接口(interface)的任何内容。顺便说一句，那条中间线是制表符补全。

我正在寻找类似于 ipython 的东西，其中可以将 ? 附加到属性名称以查看文档字符串，甚至可以将 ?? 附加到源代码:

In [1]: x = 'potato'

In [2]: x.st
x.startswith  x.strip       

In [2]: x.strip?
Type:       builtin_function_or_method
String Form:<built-in method strip of str object at 0x15e1b10>
Docstring:
S.strip([chars]) -> string or unicode

Return a copy of the string S with leading and trailing
whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping

Answer 1

首先你需要安装

gem install pry-doc

然后您可以使用 show-doc [method] 命令(别名为 ?[method])获取文档

pry> x = 'potato'
=> "potato"
pry> show-doc x.strip

From: string.c (C Method):
Owner: String
Visibility: public
Signature: strip()
Number of lines: 4

Returns a copy of str with leading and trailing whitespace removed.

   "    hello    ".strip   #=> "hello"
   "\tgoodbye\r\n".strip   #=> "goodbye"

您甚至可以使用 show-source [method] 命令(别名为 $ [method])查看源代码

pry> show-source x.strip

From: string.c (C Method):
Owner: String
Visibility: public
Number of lines: 7

static VALUE
rb_str_strip(VALUE str)
{
    str = rb_str_dup(str);
    rb_str_strip_bang(str);
    return str;
}

此示例显示的是 C 源代码，但它会向您显示实际的 Ruby 源代码(如果有的话)。考虑这个简单的类:

pry> class Foo
pry*   def bar
pry*     puts 'hello'
pry*   end
pry* end
=> nil

可以看看全类:

pry> show-source Foo

From: (pry) @ line 2:
Class name: Foo
Number of lines: 5

class Foo
  def bar
    puts 'hello'
  end
end

但也只是一个特定的方法:

pry> show-source Foo#bar

From: (pry) @ line 3:
Owner: Foo
Visibility: public
Number of lines: 3

def bar
  puts 'hello'
end

正如@banister 所建议的，您可以通过 Pry.commands.command 添加自定义命令。这样你就可以在你的 ~/.pryrc 中定义你的 ? 和 ?? 命令:

Pry.commands.command /(.+) \?\z/ do |a|
  run "show-doc", a
end

Pry.commands.command /(.+) \?\?\z/ do |a|
  run "show-source", a
end

请注意，我们需要在方法和 ? 之间留一个空格，因为 Ruby 方法可能以 ? 结尾(例如 Fixnum#zero? ) 并且这些方法会中断。一些例子:

pry> puts ?

From: io.c (C Method):
Owner: Kernel
Visibility: private
Signature: puts(*arg1)
Number of lines: 3

Equivalent to

    $stdout.puts(obj, ...)

pry> puts ??

From: io.c (C Method):
Owner: Kernel
Visibility: private
Number of lines: 8

static VALUE
rb_f_puts(int argc, VALUE *argv, VALUE recv)
{
    if (recv == rb_stdout) {
        return rb_io_puts(argc, argv, recv);
    }
    return rb_funcall2(rb_stdout, rb_intern("puts"), argc, argv);
}

pry> 0.zero?     # still works!
=> true

pry> 0.zero? ?

From: numeric.c (C Method):
Owner: Fixnum
Visibility: public
Signature: zero?()
Number of lines: 1

Returns true if fix is zero.