🚀 go-pugleaf

A couple of people have asked about the standardization status of Logo.
A few years ago the IEEE standards people hosted a discussion on this
topic that led to further discussions within the Logo community, e.g.,
at an ISTE SigLogo meeting.  It was generally agreed at that time that
it would be very difficult to draft a standard that everyone could
agree to.  There were two main categories of problems:

1.  With respect to the core of the language (the function-calling
mechanism), there is still disagreement between advocates of the
Terrapin dialect and the LCSI dialect.  In the former, there are several
exceptions to the usual argument-evaluation mechanism: IF, EDIT, and
so on.  (That is, to edit procedure foo you say EDIT FOO instead of
EDIT "FOO as the usual mechanism would require.)  In LCSI dialect, the
TO command is the only exception to the usual evaluation rules.

(Briefly, the LCSI version makes it easier to think explicitly about
the Logo language itself, because the rules are more uniform; the
Terrapin version makes it easier to write simple programs *without*
thinking too hard about the language.  It's been argued that Terrapin
style is better for young kids but LCSI style is better for more
advanced learners.)

Another difference, intellectually trivial but important if you want
a standard, is the convention for naming predicates: EQUALP versus EQUAL?.

Recently there has been some motion toward agreement.  Both Terrapin
and LCSI use ? for predicates in their most recent releases (the
original Terrapin convention), but Terrapin seems to be moving toward
the LCSI IF syntax.

2.  Even more important, the parts of the language that actual Logo users
find most important are the ones that are the most machine-specific:
graphics, sound, robotics, and other hardware-dependent extensions to
the core language.  The programming interface (e.g., the editor) also
varies widely among Logo implementations.

Anyway, the upshot is that there is no Logo standard, and so there is
no definitive online document.

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I am working on a new Logo interpreter.  Its main virtue is that it
provides exactly the same language on PC, Mac, and Unix machines.
Its other main virtue is that it will be distributed free of charge
and with source code.  It's still pretty buggy but I expect to
announce an ALPHA TEST release (that means, I know there are bugs
but you can use it anyway if you want) soon.

You can anonymous ftp to anarres.cs.berkeley.edu and get the file
pub/usermanual which is a brief online reference for this version
of Logo.  It's not "the standard" because there is none, but at
least it's accessible online!