Brian Harvey <bh@[EMAIL PROTECTED]
> wrote:
> This pops up from time to time so I have a standard response ready:
>
> --------------------
>
> At one of the Logo conferences several years ago I ran a session in
> which the possibility of a standard was discussed. Many of the Logo
> implementors were there, as well as many users. We ended up with
> the conclusion that no standard was possible, because there were too
> many serious disagreements about syntax, and also because the set of
> primitive procedures was constantly in flux.
>
<snip>
> At the
> meeting all we agreed on was that anything called Logo should have
> the word and list processing primitives (FIRST, BUTFIRST, LAST, BUTLAST,
> WORD, SENTENCE, etc.).
>
I would like to ask a few nasty questions: do you consider spelling
of primitives as part of specification? The reason for is that
Logo was offered in various languages using translated names for
primitives. Some Logo advocates even claimed that "proper" Logo
implementation will use localized names -- that using English
names would break accesibility for kids.
If you allow for variations in syntax and diffent spelling is
Pop11 a Logo? In Pop11 Clem's example looks like:
100 -> n;
if 110 = front(back([ 7 10 23])) + n then pr("VALID") endif;
In Pop11 FIRST is called 'front', BUTFIRST is called 'back',
you need parenthesis in function calls, and semicolons to
sepatate sentences. Pop11 if has rather Pascalish syntax.
Arrow ('->') denotes assignment.
BTW: Pop11 is case sensitive, lexically scoped and uses single
namespace for variables and functions.
If Pop11 is a Logo then the good news is that you have native
Logo compiler generating relatively fast code (on tight loop
about 10 times slower than C, about 3 time slower than best
Lisp compilers, about 8-10 times faster than Perl or Python,
about 1000 times faster than ucblogo (old version) or shell).
If not it may help to draw a line...
In another post Brian wrote:
> The whole point of Logo is user interface. It's all Lisp inside,
> but what makes Logo Logo is a collection of choices about what kids will
> find natural/easy/inviting.
This still begs language questions: is dynamic (or maybe lexical) scope
natural? Does case insensitivity makes things easier? Does making
newlines special help?
--
Waldek Hebisch
hebisch@[EMAIL PROTECTED]
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