LOGO

1
LOGO

• "Turtle Graphics for kids.

2
History

• Logo from Greek logos for word
• Developed by a team at MIT in 1960s
• Notable Seymour Papert
• Mathematician from Geneva
• Worked with Piaget who influenced him
• Designed as a dialect of LISP

3
Why the Turtle?

• Originally a robotic creature sat on floor
• Domed shape with shell-like electronics casing
• Slow movement of device
• Directed to move around and draw by typing
  commands at computer
• Designed to be programmed by children
• Less expensive version created on computer

4
Evolution

• 130 existing implementations
• Driven by commercial and regional factors

1977
1985
1993
1967
2003
TILOGO
Apple LOGO
Atari Logo
LOGO Writer
Logo Grafico
MicroWorlds LOGO
Mach Turtles Logo UCB Logo MSWLogo
5
Language Concepts

• Basic commands
• Control Structures
• while condition instruction list
• until condition instruction list
• repeat number instruction list
• Recursion (preferred paradigm)
• Scoping
• Global variables if not declared before use
• Local variables
• may be declared
• Input variables for functions are local

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Basic commands

• Forward 100 (FD 100) - moves the turtle forward
  100 units
• Back 50 (BK 50) - moves the turtle back 50 units
• Right 45 (RT 45) - turns the turtle 45 degrees to
  the right
• Left 90 (LT 90) - turns the turtle 90 degrees to
  the left
• Home - Returns the turtle to its origin
• ClearSceen (CS) - Erases the screen

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Features

• Graphics / Music
• Extensibles basic operations primitives.
• Working Definitions allows for user-defined new
  definitions
• Modularity
• Interactivity
• Flexibility

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Recursion

• to spiral size
• if size gt 30 stop a condition stop fd
  size rt 15 many lines of actionspiral
  size 1.02 the tailend recursive call
• end

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MSW LOGO Implemenation
Source http//www.softronix.com
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Example Square

• Turtle Moves forward and turns 90º 4 times
• REPEAT 4 FD 100 RT 90

Source http//mckoss.com/logo/
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Examples
Source http//www.yukoncollege.yk.ca/
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Future of Logo

• New Releases of LOGO
• NetLogo
• Parallel modeling and simulation
• Northwestern University
• StarLogo
• MIT