Re: help with val

[dean]

Hi Alexander
>Perhaps it helps to see it this way:
Yes it helps a lot and thank you very much for taking the trouble to
clarify things.
Best Regards
Dean




On 22 November 2016 at 20:52, Alexander Burger  wrote:

> On Tue, Nov 22, 2016 at 09:22:14PM +0100, Alexander Burger wrote:
> > > "The CDR of a symbol cell is also called VAL, and the CAR points to the
> > > symbol's tail. "
> >  ...
> > Yes, but note that this talks about the symbol's *cell*, i.e. the
> > internal representation as described in doc64/structures.
> > ...
> > On the language level, a symbol only has a value, properties and a name

Re: help with val

[Alexander Burger]

On Tue, Nov 22, 2016 at 09:22:14PM +0100, Alexander Burger wrote:
> > "The CDR of a symbol cell is also called VAL, and the CAR points to the
> > symbol's tail. "
>  ...
> Yes, but note that this talks about the symbol's *cell*, i.e. the
> internal representation as described in doc64/structures.
> ...
> On the language level, a symbol only has a value, properties and a name.
> No CDR :)

Perhaps it helps to see it this way:

1. CAR and CDR (in upper case) are the two halves of a cell

  +-+-+
  | CAR | CDR |
  +-+-+

   no matter whether this cell represents a number, a symbol or a list.


2. 'car' and 'cdr' (in lower case) are the functions to access the
   elements of pairs and lists.

♪♫ Alex
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Re: help with val

[Alexander Burger]

Hi Dean,

> from ref.html
> "The CDR of a symbol cell is also called VAL, and the CAR points to the
> symbol's tail. "

Yes, but note that this talks about the symbol's *cell*, i.e. the
internal representation as described in doc64/structures.

> but val seems to equate to car from my tests so I'm confused
> : (set 'x 3)
> -> 3
> : (car 'x)
> -> 3
> : (val 'x)
> -> 3
> : (cdr 'x)
> !? (cdr 'x)
> x -- List expected

On the language level, a symbol only has a value, properties and a name.
No CDR :)

♪♫ Alex
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UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe

help with val

[dean]

from ref.html
"The CDR of a symbol cell is also called VAL, and the CAR points to the
symbol's tail. "

but val seems to equate to car from my tests so I'm confused
: (set 'x 3)
-> 3
: (car 'x)
-> 3
: (val 'x)
-> 3
: (cdr 'x)
!? (cdr 'x)
x -- List expected