Activities/Turtle Art/Tutorials/Turtle Art and Logo - Revision history

Rdrsadhu: Migrate to GitHub

2018-07-30T10:41:08Z

Migrate to GitHub

FGrose: moved Activities/TurtleArt/Tutorials/Turtle Art and Logo to Activities/Turtle Art/Tutorials/Turtle Art and Logo: deCamelCase

2012-07-23T15:37:30Z

moved Activities/TurtleArt/Tutorials/Turtle Art and Logo to Activities/Turtle Art/Tutorials/Turtle Art and Logo: deCamelCase

← Older revision		Revision as of 11:37, 23 July 2012
(No difference)

Mokurai: /* Logo Code for TA Examples */ Add code

2011-07-30T04:44:19Z

Logo Code for TA Examples: Add code

Show changes

Mokurai: /* Left */ Spelling

2011-07-28T18:15:44Z

Left: Spelling

← Older revision		Revision as of 14:15, 28 July 2011
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	[[File:TALeft-90.png]]		[[File:TALeft-90.png]]

	No ~~suprises~~.		No surprises.

	window		window

Mokurai: /* See Also */ Add link

2011-07-10T18:06:04Z

Mokurai: /* Further Reading */ More books

2011-07-10T17:19:39Z

Mokurai: /* SetBackground */ Typo

2011-07-10T16:45:30Z

SetBackground: Typo

← Older revision		Revision as of 12:45, 10 July 2011
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	* colors holds the numeric definition of the Turtle Art color palette		* colors holds the numeric definition of the Turtle Art color palette

	That's more features ~~that~~ fit comfortably in teaching a lesson, but might not be too many in guided discovery over several sessions. With the hints given above, you should be able to see what every part of this Logo program is, but not necessarily how all of the parts fit together. That will require careful reading, including comparing definitions with their uses, and lots of experiments. For some learners, that's the best part of all. For others, including many teachers, it is a useful lesson in tolerating your own ignorance while you seek to discover something you didn't know. Anyway, we don't have to require that everybody discover everything. Students can share discoveries, which is another particularly useful lesson in itself.		That's more features than fit comfortably in teaching a lesson, but might not be too many in guided discovery over several sessions. With the hints given above, you should be able to see what every part of this Logo program is, but not necessarily how all of the parts fit together. That will require careful reading, including comparing definitions with their uses, and lots of experiments. For some learners, that's the best part of all. For others, including many teachers, it is a useful lesson in tolerating your own ignorance while you seek to discover something you didn't know. Anyway, we don't have to require that everybody discover everything. Students can share discoveries, which is another particularly useful lesson in itself.

	Once we get past those definitions, though, there is a procedure definition for tasetbackground, corresponding to the block we are testing. It is then called with the arguments 60.0 for color and 80.0 for shade, as we specified. And look! It's blue!		Once we get past those definitions, though, there is a procedure definition for tasetbackground, corresponding to the block we are testing. It is then called with the arguments 60.0 for color and 80.0 for shade, as we specified. And look! It's blue!

Mokurai: The Discoverable and the Undiscoverable in TA and Logo; Logo window

2011-07-10T16:42:56Z

The Discoverable and the Undiscoverable in TA and Logo; Logo window

← Older revision		Revision as of 12:42, 10 July 2011
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	Turtle Graphics ~~come~~ from Logo, but Turtle Art is written in Python. However, you can save any ~~Turtle Art~~ program in Logo, even a single block, and examine the code or run it in Brian Harvey's UCBLogo. ~~This allows another perspective on Turtle Art blocks, giving fine details in some cases that might not be obvious from experiment. So we can start~~ to ~~teach Logo to students who have even modest proficiency in Turtle Art, by constructing TA programs~~ and ~~saving~~ as Logo, ~~and then gradually moving to composing Logo~~ with ~~the TA code as examples~~.		Turtle Graphics comes from Logo, but Turtle Art (TA) is written in Python. However, you can save any TA program in Logo, even a single block, and examine the code or run it in Brian Harvey's UCBLogo. Go to the Journal tab and look for Save as Logo, with a turtle icon.

	This ~~is valuable because Logo is a complete programming language, which~~ Turtle Art is not. ~~Although it is [[Activities/TurtleArt/Tutorials/Turtle_Art_Turing_Machine\|Turing-complete]], which means that it could~~ in ~~principle compute any computable function~~, ~~given enough space~~ and ~~time~~, ~~it does not have many of~~ the ~~other capabilities of programming languages that can call external libraries, such~~ as ~~file handling and convenient UI design~~. ~~Of course, you~~ can ~~do that in Python, and you can call Python from Turtle Art, but that isn't~~ the ~~subject of this lesson~~.		This allows another perspective on Turtle Art blocks, giving fine details in some cases that are not obvious from experiment. So we can start to teach Logo to students who have even modest proficiency in Turtle Art, by constructing TA programs and saving as Logo, and then gradually moving to composing Logo with the TA code as examples. At the same time we can use the Logo translations to illuminate what TA is doing.

	Let's see how it might work to learn Logo from TA, or use Logo to illuminate TA.		The ability to go from TA to Logo is important because there are many things about computer languages that are inherently not discoverable without lots of hints. For example, TA provides all of its blocks on palettes, so that you can't miss any. In text-based languages, including Logo, you need to have a list somewhere outside the language interpreter. Even with all of the blocks in front of you, some are going to be mysterious. You don't know how they do what they do, or you don't even see them do anything at all unless you know what other block to use next. We discuss this further in [[The Undiscoverable]]. Of course, at some point, if you really want to know what is going on, you have to read the source code.

			Having a path from TA to Logo is valuable because Logo is a much fuller programming language than TA. Although it is [[Activities/TurtleArt/Tutorials/Turtle_Art_Turing_Machine\|Turing-complete]], which means that it could in principle compute any computable function, given enough space and time, it does not have many of the other capabilities of programming languages that can call external libraries, such as file handling and convenient UI design. Of course, you can do that in Python, and you can call Python from Turtle Art, but that isn't the subject of this lesson.

			Let's see how it might start to work to learn Logo from TA, or use Logo to illuminate TA.

	==Logo Code for TA Blocks==		==Logo Code for TA Blocks==
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	===start===		===start===

	A new TA session starts with just a start block. Click it, and nothing visible happens.		A new TA session starts with just a start block. Click it, and nothing visible happens. (In older versions, you will have to get a start block from the Flow palette, the one with the two arrows going in a circle.

	[[File:TAStart.png]]		[[File:TAStart.png]]
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	This says to open a display window, and then uses "to" to define a procedure named "start" with contents a blank line. The keyword "end" ends the definition. So we were right. The start block all by itself does nothing, but goes through a process to get that result.		This says to open a display window, and then uses "to" to define a procedure named "start" with contents a blank line. The keyword "end" ends the definition. So we were right. The start block all by itself does nothing, but goes through a process to get that result.

	Of course in TA we don't open display windows, because one is always open.		Of course in TA we don't open display windows, because one is always open. Here is what the window looks like in UCBLogo, with a triangle for the turtle.

			[[File:BXLogoWindow.png]]

	===Start-Forward===		===Start-Forward===

	All right, that didn't tell us a lot~~, but maybe~~ this will help.		All right, it's a start (haha) but that didn't tell us a lot. Maybe this will help.

	[[File:TAStartForward-100.png]]		[[File:TAStartForward-100.png]]

Mokurai: /* SetBackground */ New features in code, and how to understand them

2011-07-10T16:24:27Z

SetBackground: New features in code, and how to understand them

@@ Line 65: / Line 65: @@
 [[File:TASetBackground-60-80.png]]
-Oh. A lot more goes on here. Turtle Art told Logo about how it handles colors. Down at the bottom, though, there is a procedure definition for tasetbackground, which is then called with the arguments 60.0 for color and 80.0 for shade, as we specified. And look! It's blue!
+Oh. A lot more goes on here. Turtle Art told Logo about how it handles colors. I won't explain everything in detail, but let's make a list of bits of Logo we haven't seen yet.
   window

Mokurai: /* Left */ pretty-print

2011-07-10T15:58:25Z

Left: pretty-print

← Older revision		Revision as of 11:58, 10 July 2011
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	window		window
	to turtleblocks_0		to turtleblocks_0
	left 90.0		left 90.0
	end		end

← Older revision		Revision as of 14:06, 10 July 2011
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	* [http://www.eecs.berkeley.edu/~bh/logo.html UCB Logo]		* [http://www.eecs.berkeley.edu/~bh/logo.html UCB Logo]
	* [http://dailypapert.com/ The Daily Papert]		* [http://dailypapert.com/ The Daily Papert]
	* [http://el.media.mit.edu/logo-foundation/ Logo Foundation]		* [http://el.media.mit.edu/logo-foundation/ Logo Foundation]
			* [http://el.media.mit.edu/logo-foundation/products/books.html Logo books]

	==Further Reading==		==Further Reading==

← Older revision		Revision as of 13:19, 10 July 2011
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	* ''Mindstorms: Children, Computers, and Powerful Ideas'', by Seymour Papert. Where Logo and Turtle Graphics got started.		* ''Mindstorms: Children, Computers, and Powerful Ideas'', by Seymour Papert. Where Logo and Turtle Graphics got started.
			* ''LogoWorks: Lessons in Logo'', by Sheila Cory and Margie Walker
			* ''Teaching With Logo'', by Molly and Daniel Watt
			* ''Advanced Logo, A Language for Learning'', by Michael Friendly
			* ''Computer Science Logo Style, Second Edition'', by Brian Harvey. Three volumes.

			There are also many books on using Logo to teach various subjects, mostly in math.