Re: [LogoForum] Logo: Tests for compliance.

The message below is being cross-posted from the LogoForum. Please
reply here at comp.lang.logo and it will be cross-posted back to the
LogoForum. The original author of this message is
pavel@elica.nospam.net.


Waldek Hebisch wrote:
> If you allow for variations in syntax and diffent spelling is
> Pop11 a Logo? In Pop11 Clem's example looks like:

Can Pop11 treat data (e.g. a list) as instructions. Can Pop11 assign a
value to a variable which name is computed at run time?

Right now for me it is hard to say whether something is Logo or is not
Logo. I expect that Logo is a fuzzy (cloudy) thing, so there might be
languages (or better say programming environments) which are 50%
Logo-like... or 20% Logo-like.... Most likely if we classify all Logos
we could see some piling-up around the core features of the majority of
Logos... but we could also see some branches/tentacles which bridge a
smooth path from Logo to some other programming languages and
environments. OOP, 3D, multimedia, compilers, networking are all
extensions to the core which bring Logoist and Nonlogoists closer.

For example, a Pascal language + Turtle graphics library and list
processing could be positions somewhere between Logo and Pascal... maybe
closer to Pascal than to Logo, but by all means it will have some Logo
features.

So Logos may form a bell-shaped normal distribution... Or may not?!?

If we have the list of features of two things, then by finding an
appropriate metrics we can calculate the 'distance' between them. Now,
these two things could be two dialects of Logo, or Logo and Lisp, or
Logo and Boxer, or Logo and Pop11. By having the distance we could say
how close are two things.

Pavel

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Pavel,

maybe it would be worth a try using my list of primitive classes,
and define the number "Logoishness" in the range of 0..100
for every primitive in the list. ;-)
Then one can add the "Logoishness" of the primitives found in each dialect.
Of course it is difficult to define those numbers. ;-)
But maybe this helps in the categorization process?

Andreas

> If we have the list of features of two things, then by finding an
> appropriate metrics we can calculate the 'distance' between them. Now,
> these two things could be two dialects of Logo, or Logo and Lisp, or
> Logo and Boxer, or Logo and Pop11. By having the distance we could say
> how close are two things.
>
> Pavel

pavel@elica.nospam.net wrote:
>
> Waldek Hebisch wrote:
> > If you allow for variations in syntax and diffent spelling is
> > Pop11 a Logo? In Pop11 Clem's example looks like:
>
> Can Pop11 treat data (e.g. a list) as instructions. Can Pop11 assign a
> value to a variable which name is computed at run time?
>

Sure. pop11_compile compiles list to machine code, executes and
gives back result:

: [2 + 2] -> code;
;;; DECLARING VARIABLE code
: pop11_compile(code) =>
** 4
:

valof allows you to access variables with given name:

: "code" -> name;
;;; DECLARING VARIABLE name
: valof(name) =>
** [2 + 2]
: "name" -> valof(name);
: code =>
** name
:

> Right now for me it is hard to say whether something is Logo or is not
> Logo. I expect that Logo is a fuzzy (cloudy) thing, so there might be
> languages (or better say programming environments) which are 50%
> Logo-like... or 20% Logo-like....

For languages users care if program runs on different implementation,
or how much effort is needed to change program so that it runs.

--
Waldek Hebisch
hebisch@math.uni.wroc.pl