LOGO
A powerful programming language built to be easy for children to use, conceived by Seymour Papert in 1966. Logo is essentially a dialect of LISP without the parentheses that traditional LISP requires. It has been implemented in many versions including Brian Harvey's UCBLogo and the multimedia authoring toolkit Hyperstudio. (A bit of Logo history can be found here: https://logothings.wikispaces.com/.)
Sometimes there is confusion between the full-fledged programming language and the graphics module that implements turtle graphics.
There are lessons to be learned in all of these systems if OLPC application developers wish to stand on the shoulders of giants rather than reinvent the wheel. It can be considered one of the Predecessors of OLPC.
To see the broad scope of this software around the world look at the In other languages section of the Wikipedia
XO activities
LOGO, LOGO-inspired, and turtle-graphics activities for the XO:
- Turtle Art is included in current builds. It is a visual programming language with snap-together elements. The programs control a turtle, but lack parameters and data structures (lists).
- Etoys, is on the XO, inspired by LOGO, includes turtle-like cars and things.
- Python is on the XO, allowing installation of PyoLogo, PyLogo, or xturtle.py (see below)
- Loggerhead is a software idea, with many of the concepts already implemented in the above software.
- Berkeley Logo is on the XO, but not yet fully Sugarized (uses real files instead of the journal, etc.). It's a basically old-fashioned Logo, programmed in text, one turtle -- like you had on your Apple II, only more memory and better debugging support.
Alternatives
- LogoWiki
- http://www.logowiki.net (site is gone) web archive
Recently developed by Alan Kay and friends. Built on top of JavaScript.
- Curly Logo
- http://www.amberfrog.com/logo/
Another JavaScript logo implementation, requiring SVG support in the browser. It has already been tested on the laptop in xulrunner.
xturtle.py is a new turtle graphics module, which could (or should?) replace the old turtle.py—if not in python's standard distribution, then at least in practical work.
- Logo inside Flash (in Spanish)
- http://neoparaiso.com/logo/logo-flash.html
It can't save procedures from session to session but it doesn't need to be installed (which is sometimes forbidden in school computer labs). Probably saving of sessions could be implemented given a server-side piece to communicate with.
Works under Python (which, it seems, will be a given in the laptop). A fairly traditional Logo implementation, but without much of a GUI (maybe useful with xturtle)
- PyoLogo
- PyoLogo
- Scratch
- http://llk.media.mit.edu/projects/summaries/scratch.shtml
Runs under Squeak.
Now running on the XO with the new GUI! It can be translated (without recompilation) to languages that have their character sets in 1-byte encodings. It was been translated to Spanish (LogoES). The only essential work needed is to add support for GTK I/O which is a relatively simple task. UCBLogo was written with the constraints of 640k PCs in mind, so it's very small. (glogo is a logo interpreter, using ucblogo as the core and the GNOME libraries to provide a graphical user interface—if I remember correctly this actually runs ucblogo as a subprocess, and redefines the graphical commands to print output that is then interpreted by the GUI frontend; as such it is rather limited.)
Needs testing, packaging and materials (maybe it's still too beta). Looks like turtle graphics but a C-like language.
Needs a migration to Linux. Has lots of learning material on the Internet. Based on the UCBLogo interpreter.
Needs a migration to Linux
Freeware, but not open-source. Requires Java. Actively developed; high quality. Like StarLogo, it emphasizes highly concurrent multi-agent (multi-turtle) programming.
- TurtleTracks Logo (by Daniel Azuma)
- http://turtletracks.sf.net
UCBLogo compatible. Open source, written in Java (so supports Unicode) by a PhD student of Brian Harvey's. Has full TurtleGraphics implementation and extra features like multithreading
- E-Slate Logo (by George Birbilis and RA.CTI)
- http://e-slate.cti.gr
Open source extension of TurtleTracks Logo (source for the extended TurtleTracks Logo is included in the E-Slate distribution) for talking to Java components (TELL, ASK, EACH, TELLALL commands) and added support for dynamic localization of commands (via Java resourcebundles), where the base (English) language and one other language can be intermixed freely in Logo programs
- KTurtle
- http://edu.kde.org/kturtle
Actually not a LOGO clone, but a programming environment for kids. Main features: translatable programming commands (currently around 20 supported languages) using unicode. The next version will be a full rewrite, a preview of this will ship with KDE4. No 1.0 release yet. This programming language is purely educational.
- JavaLogo
- http://javalogo.sourceforge.net/
Very basic implementation of turtle graphics concepts in Java and Swing. Can be used to demonstrate as little or as much of the entire object orientation paradigm and multi threading exposed by Java.
- Web Turtle
- http://www.sonic.net/~nbs/webturtle/
Another BASIC-like web environment for playing with turtle graphics, by the author of Tux Paint.
Necessary features
This section and the next are sort of obsolete, since UCBLogo now runs on the XO!
- Standard Language syntax (as close as possible to Brian Harveys' UCBLogo)
- No funny parentheses: fd(10)
- I don't mind having to add spaces between words: 1 + 2, instead of 1+2 (as in UCBLogo)
- Multilingual support
- Stable and attrative GUI
- Trigonometric functions, sqrt, exp, power, log, ln (to be able to draw at least figure 24 accurately)
- Friendly error messages: No "syntax error #342342" (No trace backs?)
Requested Features
UCBLogo has these:
- Optional inputs, like UCBLogo
- Write a basic GTK interface for UCBLogo so that it can be run as a Sugar Activity
- SetPenColor. With RGB colors too (not just 16 basic colors)
- Extensions to interact with OS to allow scripting
But not (yet) these:
- ColorUnder (or "Pixel"). This is useful to solve this kind of problems.
- Extensions to exploit hardware features (eg. ways to read and write to the ports)
- XML-RPC Interface to enable inter-application communication
Opinions
- LOGO could be an excellent way to introduce programming and logic. I started with it!! I think this should be a starter way, but definitely and improved new version (with more than one "turtle" at least). Today's children can understand easily and faster everything related to computers. And could be some kind of art too if are given the proper tools. (filling closed shapes, or maybe object oriented). Could be a very nice piece of soft!! --Gandolfi
- LOGO is certainly a fun way to learn programming and/or to just play with a computer. Many modern implementations have multiple screen turtles. Perhaps at its simplest this can be found in MSWLogo (for Windows). - FREE. Newer flavors of LOGO are StarLogo and NetLogo. They offer powerful ways of controlling large swarms of turtles and their environment - the great benefit being to encourage truly distributed ways of thinking and programming. --L Pfeffer
- The only real issue with LOGO that I can think of is it's English keywords. It would be fairly simple to redefine the starting dictionary as abstract tokens (even single characters in a special character set, with a corresponding symbol font) and then create regional "include files" which map them back into English words, or Swahili, or icons. I understand the desire to make programming a visual exercise in dragging colourful blocks, but programming can also be inherently textual because of it's links with literature, and a good LOGO progamming session can be like a conversation. Please ensure the kids have a real option which language that conversation is in, and even a chance to develop their own. -- Jeremy Lee
- PyLogo is a bit rough in some places, but I'll try to speak to its advantages and disadvantages. In this context the key advantage is really that environments built for Python are available to PyLogo (and vice versa), including some neat interfaces like xturtle. I think offers some real potential for a gradual learning curve to more advanced programming. A negative is that it's kind of slow (though lots of Logo implementations are on the slow side). Another negative is that it uses Python's execution model, which means that you can't have high levels of concurrency ala NetLogo (without using an alternate interpreter like Stackless). A positive is that reimplementing Logo without using Python's callstack is probably not a big deal (Logo is, after all, a simple language). A positive is that it's a low risk, since it is simply a small library on top of a platform OLPC will already be using. A negative is that Python doesn't do well running untrusted code, and this is just as true for PyLogo. A reimplementation could resolve this as well. In its current state PyLogo should be okay for doing multilingual programming, though no one has tried that; nevertheless it can be unicode aware and the primitives can have both aliases and be renamed arbitrarily, unlike Python. -- Ian Bicking (PyLogo author)
- Vaporware?
- There are more than 150 different versions of LOGO. Few of them are free, fewer are multi-language, fewer have a nice GUI, none? On top of that Turtle Graphics is not really LOGO. Kturtle is just Turtle Graphics and with the current version of KTurtle not even construct 24 can be drawn accurately. Basic information on the 161 known Logos can be found Logo Atlas including their manuals. Interesting work has been done in French, Portuguese and Spanish speaking countries that are more language independent.
- Maybe older versions couldn't, but the latest KTurtle has procedures and recursion. (I'm not sure which of the images you mention is construct 24.) --IanOsgood 16:04, 14 November 2007 (EST)
Both NetLogo and StarLogo need Java, no? So Logo is still vaporware for our practical purposes.
- NOTE that any and all software is grist for the mill. If NetLogo would be an asset to the OLPC, then we should try to set up a project to write a subset of NetLogo in Python which is supported by OLPC.
- And if two versions of LOGO are vaporware that does not mean the OLPC can't run LOGO. UCBLogo will run perfectly well on the OLPC as it stands. The only essential work in adapting UCBLogo is to make it use GTK for its I/O.
Etoys comes with a multi-agent system which is inspired by StarLogo and NetLogo. To try it out, launch Etoys on the B1 machine or in the emulator, press the "All" button, navigate to ParticleDyeInWater.pr, and press OK.
External Links
- Why Use Logo? An Overview of Logo in Education
- http://www.terrapinlogo.com/why-use-logo.php
- Logo Web Site in Spanish
- http://neoparaiso.com/logo/
- Logo Web Site in Brazil
- http://br.geocities.com/projetologo/logo/index.html