LOGO-L> mirror mode 
Author Message
 LOGO-L> mirror mode

George Mills and Brian Harvey,

I have a suggestion for a Logo enhancement.
(I apologize if it has been suggested before.)

I would like to be able to set MIRROR mode
which causes LT and RT to be reversed.

This would enable you to use a procedure
which draws a right-facing cat when you
want to draw a left-facing cat.

More importantly, it would round out one of Logo's
great strengths: teaching geometric thinking,
especially in the field of symmetry.

The basic 2-D geometric transformations are:

   1. translation (moving)
   2. rotation (turning)
   3. scaling (sizing), and
   4. refection (mirroring).

The first three are easy in Logo, the fourth
should be made easy too.

Thanks,
Keith Enevoldsen
---------------------------------------------------------------





Wed, 24 Nov 1999 03:00:00 GMT  
 LOGO-L> mirror mode

Nice Idea.
I'd also like to add a "Standard Mode" one day.
In which 0 degrees is to the right as it should be.

Quote:

> George Mills and Brian Harvey,

> I have a suggestion for a Logo enhancement.
> (I apologize if it has been suggested before.)

> I would like to be able to set MIRROR mode
> which causes LT and RT to be reversed.

> This would enable you to use a procedure
> which draws a right-facing cat when you
> want to draw a left-facing cat.

> More importantly, it would round out one of Logo's
> great strengths: teaching geometric thinking,
> especially in the field of symmetry.

> The basic 2-D geometric transformations are:

>    1. translation (moving)
>    2. rotation (turning)
>    3. scaling (sizing), and
>    4. refection (mirroring).

> The first three are easy in Logo, the fourth
> should be made easy too.

> Thanks,
> Keith Enevoldsen

--
===============================================================

http://www.softronix.com/
The www page contains some very powerful educational software.
Our single most important investment is our kids.

---------------------------------------------------------------





Wed, 24 Nov 1999 03:00:00 GMT  
 LOGO-L> mirror mode

o Added memory to memory bitmap operation (see BITPASTETOINDEX).
     This command will allow fast and flicker free animation.
     But you have to LEARN how to do animation to use it, it's not
handed
     to you on a silver platter. Learning is the FUN part.

   o Fixed TAN (Tangent) and RADTAN in library.

   o Added Inverse Trig functions (see ARCSIN, ARCCOS, RADARCSIN
     and RADARCCOS).

   o Comments in repeat loops is fix (Thanks to Brian for
     a sneak preview of the fix).

   o Editor can now handle up to 4 Gigabytes rather than 64k.
     This is available only to Win32 based versions.

   o Editor now allows you to print your code.
     This is available only to Win32 based versions.

   o Modified BITLOAD command to output the size of Bitmap loaded.

   o Fixed numerous errors in online help.

   o Added SELECTBOX function. This allows you to pass a list of choices
to
     a function that will display those choices and will output which
choice
     the user picked. (e.g. SELECTBOX [Choose a Color] [Red Green Blue]
     will output 1 if the user chooses Red and 2 for green)

   o Implemented SHELL command to lauch other Windows applications.

   o Rebuilt with Borland Version 5.02

   o Fixed SETTEXTFONT not handling negative height required by some
     fonts.

   o Modified install program to register MSWLogo such that if you
double on
     a .LGO file in the explorer it will start MSWLogo and load that
project
     file. Available on Win32 based versions.

   o The Font Setting in the Editor now effects the commander as well.
If you
     prefer a fixed pitch font try changing it to something like
"Courier New".

--
===============================================================

http://www.softronix.com/
The www page contains some very powerful educational software.
Our single most important investment is our kids.

---------------------------------------------------------------





Thu, 25 Nov 1999 03:00:00 GMT  
 LOGO-L> mirror mode

I added some error checking cleanup in version 5.3 and
it surfaced a bug in two LOGOLIB routines SOUNDON and SOUNDOFF
functions.

To fix it replace INPORT with INPORTB in both these functions
(SOUNDON and SOUNDOFF) in the LOGOLIB directory.

--
===============================================================

http://www.softronix.com/
The www page contains some very powerful educational software.
Our single most important investment is our kids.

---------------------------------------------------------------





Thu, 25 Nov 1999 03:00:00 GMT  
 LOGO-L> mirror mode

Quote:

> I would like to be able to set MIRROR mode
> which causes LT and RT to be reversed.

>Nice Idea.
>I'd also like to add a "Standard Mode" one day.
>In which 0 degrees is to the right as it should be.

I replied directly to Keith about this but I guess I should raise
the question with the group too.  After I posted the implementation
of MIRROR using COPYDEF he suggested adding it to the standard
library, and now along comes George with another proposed mode.

I'm afraid that this could go on forever.  Already in Berkeley Logo
we have the following modes:

pen position (UP or DOWN)
pen mode (PAINT, ERASE, or REVERSE)
turtle motion mode (WINDOW, WRAP, or FENCE)
case sensitivity in word comparisons (TRUE or FALSE)
COPYDEF allowed for primitives (TRUE or FALSE)
print names of procedures while loading (TRUE or FALSE)
remember turtle's moves (REFRESH or NOREFRESH)

and probably more that I'm forgetting.  People got confused, as we
discussed not long ago, about the fact that the pen position is
independent of its mode; that's not true in all Logo dialects.

In the design of the Macintosh, one of the religious principles that
they followed was "modeless computing."  The user should never have to
remember anything about the past history of the computation to be able
to predict what the next keystroke (or mouse click) will do.

So, for example, traditional word processing was done by first giving a
command (say, DELETE) and then indicating what text to delete.  In between
those two steps, the word processor is in a mode: "whatever text the user
indicates should be deleted."  Instead, on the Mac, first you select some
text, and *then* you give the delete command.  This really does make life
easier for the user, I think, although I also think the Mac folks were
needlessly extreme about modelessness.

In Logo, if I were inclined to invent new modes, one would be about
tokenization.  I know of three Logo tokenization rules:

old LCSI:  2+3 means five; [2+3] is a three-word list.
new LCSI:  2+3 is a three-letter word; [2+3] is a one-word list.
Terrapin:  2+3 means five; [2+3] is a one-word list.

The two LCSI rules are simple and consistent; the plus sign always
separates words (old LCSI) or never separates words (new LCSI).
The Terrapin rules are complicated to explain, but are more likely
to "do what I mean" in practice.  Berkeley Logo uses Terrapin rules,
but maybe there should be three tokenization modes?

So I am reluctant to add any modes, even as library procedures,
to the language definition.  I'd rather let teachers who want to
emphasize some particular idea invent their own situation-specific
modes if necessary.

Other opinions?



Thu, 25 Nov 1999 03:00:00 GMT  
 
 [ 9 post ] 

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