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Re: Re: Bug: symbol recreates itself suddenly

  • To: mathgroup at smc.vnet.net
  • Subject: [mg86829] Re: [mg86809] Re: Bug: symbol recreates itself suddenly
  • From: DrMajorBob <drmajorbob at bigfoot.com>
  • Date: Sat, 22 Mar 2008 00:54:42 -0500 (EST)
  • References: <9457525.1205860522819.JavaMail.root@m08> <frqpu5$59m$1@smc.vnet.net> <20859482.1206092036607.JavaMail.root@m08>
  • Reply-to: drmajorbob at longhorns.com

> Please don't ask why am I doing this.

Too late, but I won't ask again, since I'm not, in fact, the least bit  
curious why you're doing it.

If you DON'T do it, however, you won't have this problem.

As for me, when I see a symbol that starts with a capital, I assume it's a  
built-in, created by Wolfram or a trustworthy 3rd party package. I don't 
change built-ins, and I never name my own variables with capital letters ,  
so it's trivial to see which are mine and which are not, at a glance. That  
saves me a second here, a minute there... over time, it adds up. Maybe  
we're talking a whole HOUR by now. (Ha!)

But that's OK, do it your way. (If you can.)

> This is not forbidden according to
> manual - and it worked in 4.0, 5.0, 5.2 versions. It should work in 6.0
> either. (Or it should be documented.)

MANY things should be documented. ('Nuff said on THAT touchy topic.)

Bobby

On Fri, 21 Mar 2008 01:56:25 -0500, Severin Posta  
<severin at km1.fjfi.cvut.cz> wrote:

> This is definitely NOT the correct answer. The correct answer is (should  
> be)
>
> "Symbol E not found."
>
> By all means this is really a bug.
>
> It has far-reaching consequences. Using symbol E afterwards can lead to
> mistakes because Mathematica thinks (suddenly!) this is again Euler
> constant, not general symbol.
>
>
>
> Please don't ask why am I doing this. This is not forbidden according to
> manual - and it worked in 4.0, 5.0, 5.2 versions. It should work in 6.0
> either. (Or it should be documented.)
>
> Severin Posta
>
> "DrMajorBob" <drmajorbob at bigfoot.com> wrote in message
> news:frqpu5$59m$1 at smc.vnet.net...
>> "In[6]:= ?E
>>
>> E is the exponential constant e (base of natural logarithms), with \
>> numerical value \[TildeEqual]2.71828. >>
>>
>> (* THIS IS NOT CORRECT ANSWER *)"
>>
>> Oh yes, it certainly IS the correct answer.
>>
>> Why do you want to Remove built-in constants? (Regardless of whether it
>> might or might not "work" to do so?)
>>
>> Bobby
>>
>> On Tue, 18 Mar 2008 04:50:49 -0500, Severin Posta
>>
>> <severin at km1.fjfi.cvut.cz> wrote:
>>
>>> It seems to me that after Remove[symbol] some times the symbol is
>>> "recreated" without notice. Consider the following example.
>>>
>>> How to repeat:
>>>
>>> In[1]:= $Version
>>>
>>> Out[1]= "6.0 for Microsoft Windows (32-bit) (April 20, 2007)"
>>>
>>> In[2]:= Unprotect[E]; ClearAttributes[E, {Constant, Protected,
>>>
>>> ReadProtected}]; Remove[E];
>>>
>>> In[4]:= ?E
>>>
>>> During evaluation of In[4]:= Information::notfound: Symbol E not
>>> \ found. >>
>>>
>>> In[5]:= Solve[E == 2]
>>>
>>> Out[5]= {{Global`E -> 2}}
>>>
>>> (* ?! *)
>>>
>>> In[6]:= ?E
>>>
>>> E is the exponential constant e (base of natural logarithms), with \
>>> numerical value \[TildeEqual]2.71828. >>
>>>
>>> (* THIS IS NOT CORRECT ANSWER *)
>>>
>>>
>>>
>>> Severin Posta
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>> -- 
>>
>> DrMajorBob at longhorns.com
>>
>
>
>
>



-- =

DrMajorBob at longhorns.com


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