T for true, and true for T (was Re: [Maxima] emaxima's macros bug?)

In lisp, T is short for the canonical truth value "true".
It seemed to work that way in Macsyma as well. Setting $T
to something else, or perhaps nothing, might fix it.

It used to be something like (makunbound '$T)  would do
it in maclisp.
probably (make-unbound '$t)  in ANSI CL.

I wouldn't guarantee this as a solution without some
testing.

RJF


Jay Belanger wrote:
> Valerij Pipin <pip@iszf.irk.ru> writes:
> 
> 
>>Hi,
>>
>>I'm writing an introduction to itensor with help of emaxima mode.
>>I found an unusual behaviour. Look in the attachment.
>>The name of tensor "t" was replaced by name "true" (lisp's caused??) after TeX 
>>updation the  cell. Everything is ok when another name is used.
> 
> 
> Maxima seems to interpret that particular "t" as "true".  I don't
> think this is peculiar to emaxima mode; in an ordinary maxima session,
> I get the following: 
> (C1) permut_ten(T([i],[l,m],p,q),covd);
> 
> (D1) 		    permut_ten(T([i], [l, m], p, q), covd)
> (C2) tex(%);
> 
> $$\mathrm{permut\_ten}\left(\mathbf{true}\left(\left[ i \right] 
>  ,\linebreak[0]\left[ l,\linebreak[0]m \right] ,\linebreak[0]p
>  ,\linebreak[0]q\right),\linebreak[0]\mathrm{covd}\right)$$
> (D2) 				     FALSE
> 
> After playing with it some, it seems that in t,T, and t(), the "t" is
> not interpreted as "true", but in T(), the "t" is interpreted as
> "true".  Odd, I think, but I'm sure there's a good reason for it.
> 
> (C17) t; T; t(); T();
> 
> (D17) 				       t
> (C18) 
> (D18) 				       T
> (C19) 
> (D19) 				      t()
> (C20) 
> (D20) 				      T()
> (C21) tex(t);tex(T);tex(t());tex(T());
> 
> $$t$$
> (D21) 				     FALSE
> (C22) 
> $$T$$
> (D22) 				     FALSE
> (C23) 
> $$t\left(\right)$$
> (D23) 				     FALSE
> (C24) 
> $$\mathbf{true}\left(\right)$$
> (D24) 				     FALSE
> (C25) 
> 
> Jay
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