From: SonOfLilit <sonoflilit@...>
Date: 2007-06-27T06:55:36+09:00
Subject: Re: Fun about inspect

I've given up on #inspect.

I use my #dump! method (VERY useful, search the list for it, the best
four lines I've ever written) and use #to_yaml within it.


Aur

On 6/27/07, Victor Zverok Shepelev <vshepelev@imho.com.ua> wrote:
> Hi all.
>
> By some complex reasons, I've made an interesting conclusion: for
> "serializable" types it's always good to have eval(obj.inspect) == obj
>
> For me it was a good thought, because previously, I've always doubt what
> #inspect should do, and typically have ended with #inspect as alias for
> #to_s
>
> Here is a dumb test for some core classes:
>
> # dumb testing function
> # tests, if eval(obj.inspect) == obj, and if any
> # parsing errors are thrown by evaluating
> #
> def tst(obj)
>   begin
>     print "testing %-10.10s: " % obj.class.name
>     res = eval(obj.inspect)
>     if res == obj
>       puts 'OK'
>     else
>       print 'WRONG : '
>       puts "\t%-7s => %-7s" % [obj.inspect, res.inspect]
>     end
>   rescue Exception
>     puts "ERROR"
>   end
> end
>
> #the tests itself
>
> tst(5)         #=> OK
> tst("str")     #=> OK
> tst(RuntimeError.new)     #=> WRONG : #<RuntimeError: RuntimeError> => nil
>
> tst([1,2,3])   #=> OK
> tst(:a => 1)   #=> OK
> tst(Time.new)  #=> ERROR
>
> There are several interesting things to note:
> * basic types (Numeric, String, Array, Hash) are all behave good here.
> * Exception descendants are evaluated to nil, which can be considered OK, as
> we typically not plan to serialize and store exceptions. Even in this case,
> results of #inspect are evaluated without any error!
> * But Time is a bad guy! It's #inspect result is something like "Wed Jun 27
> 00:36:12 +0300 2007" and is equal to it's #to_s result and can't be
> evaluated in any manner. I think, it's not the most reasonable variant.
>
> What do you think?
>
> V.
>
>
>