>This is surprising to me. Until this time, I thought that Papert
>hasdevelopped a fixed and complete concept around Logo, from
>which it follows (for me) the a has written anywhere what Logo
>should be and what not. But as you say, this is not the truth.
>How makes the different versions since Papert got the idea of Logo ?
Logo isn't something Papert did all by himself, or all at once.
Wally Feurzeig started a project to use computer programming with
kids in school, started with a different interactive language,
found problems with it, made up the name "Logo" for a proposed
language that would feature words (hence the name) instead of
numbers, and put together a team including Papert. The first
language called "Logo" looked quite different from any current
This all happened slightly before my time, but my impression is
that Papert's biggest contribution wasn't anything about the
structure of the Logo syntax, but rather the turtle graphics
Having said that, pretty much every Logo dialect developed in
the western hemisphere is derived from one of two versions,
the MIT Logo for the Apple (sold and further developed by
Terrapin) and LCSI's Apple Logo. Both the MIT Logo group and
LCSI were organized by Papert, so in some sense he's the father
of most current dialects.
But the real answer is, there are different versions because
Logo people keep thinking about improvements and about responding
to changes in technology. Since Logo isn't heavily used in
industry, we aren't subject to the sort of economic pressure
that leads other languages into ISO/ANSI/IEEE standardization
>Is there a definable subset, which is common to all Logos ?
A bunch of us once tried to sketch out a Logo standard. The
only thing we could all agree on was the word/list primitive
set (WORD, SENTENCE, LIST, FPUT, LPUT, FIRST, LAST, BUTFIRST,
BUTLAST). Everything else has varied among dialects, usually
for defensible reasons, not just arbitrary choices.