Re: Why are these functions not equal?

[Hao Wu <wuhao.wise@...>]

On Sat, Mar 29, 2014 at 12:43 AM, Coda Highland <chighland@gmail.com> wrote:
> On Sat, Mar 29, 2014 at 12:41 AM, Dirk Laurie <dirk.laurie@gmail.com> wrote:
>> 2014-03-29 9:35 GMT+02:00 Coda Highland <chighland@gmail.com>:
>>> On Sat, Mar 29, 2014 at 12:17 AM, Dirk Laurie <dirk.laurie@gmail.com> wrote:
>>>> The Lua 5.2 manual says:
>>>>
>>>>> Equality between function values has changed. Now, a function definition
>>>>> may not create a new value; it may reuse some previous value if there is
>>>>> no observable difference to the new function.
>>>>
>>>> This remark says "may". It is surprising that in the simplest possible case,
>>>> it does not happen.
>>>>
>>>> ~~~~
>>>> $ lua
>>>> Lua 5.2.3  Copyright (C) 1994-2013 Lua.org, PUC-Rio
>>>>> x=function() end; y=function() end
>>>>> print(x==y)
>>>> false
>>>>> print(string.dump(x)==string.dump(y))
>>>> true
>>>> ~~~~
>>>>
>>>
>>> Is this a quiz question or a legit one? Because I know the answer.
>>
>> Well, I don't!
>>
>
> Answer: Their upvalues differ. The function stored in y has x as an
> upvalue; the function stored in x does not.

Why does it save a value it doesn't even refer to? If this is the
case, then none of the functions would be the same?

>
> /s/ Adam
>