Thanks, would be even better, if there were possibility to swich orientation with mode(...) https://docs.python.org/3/library/turtle.html#turtle.mode don't know how to call this mode, maybe 'crt_style' or so? now there are 'standard', 'logo', or custom 'world' On Fri, Mar 13, 2015 at 5:48 PM, Andre Roberge <andre.roberge@gmail.com> wrote:

On Fri, Mar 13, 2015 at 8:52 AM, Jurgis Pralgauskis < jurgis.pralgauskis@gmail.com> wrote:

...

Hi,

usually in computer graphics Y is counted to increase downwards. I casn do it with: setworldcoordinates(0, 400, 600, 0)

but then, "right(..)" turns to the left :/

I could swap: right, left = left, right

but on errror I get a bit misleading message

...

...

...

right() Traceback (most recent call last): File "<pyshell#10>", line 1, in <module> right() TypeError: left() takes exactly 1 argument (0 given)

I thought to make this hack for kids, so better clearer error msgs...

...

Any Ideas?

http://bugs.python.org/issue23660 (includes a proposed "permanent" fix).

André

...

Thanks :) -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

_______________________________________________ Edu-sig mailing list Edu-sig@python.org https://mail.python.org/mailman/listinfo/edu-sig

-- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

Hi Andre, I'm sorry that you did not like my response when I was triaging all of the open Turtle issues. I am happy to change the status back to open. All that you needed to do was ask politely and give me a chance, as a volunteer, to have the time to do so. Regards, Carol

On Jun 17, 2018, at 1:41 PM, Andre Roberge <andre.roberge@gmail.com <mailto:andre.roberge@gmail.com>> wrote:

So, a little over 3 years after I submitted a bug report (see previous conversation below) **with a fix** so that no one would have to explain why "right()" could result in a turtle turning left, and vice-versa, my submission was refused and the bug report was closed with the following explanation:

" I'm closing this issue since introducing this suggested change would impact teaching materials and resources that have already been published. This would be a change that would break compatibility. " I'm curious: does anyone on the edu-sig list has written teaching material for the turtle module that sets world coordinates such that left and right are reversed? If so, how do you explain it to students?

Rant: This is the third time that I submit either a bug report for cPython **with** a proposed fix, or simply a fix for an existing bug report and that it is either rejected or dismissed with no alternative solution proposed. Thankfully, the folks here on edu-sig have been much more supportive since I joined, almost 15 years ago. /rant

André

On Fri, Mar 13, 2015 at 12:48 PM Andre Roberge <andre.roberge@gmail.com <mailto:andre.roberge@gmail.com>> wrote:

On Fri, Mar 13, 2015 at 8:52 AM, Jurgis Pralgauskis <jurgis.pralgauskis@gmail.com <mailto:jurgis.pralgauskis@gmail.com>> wrote: Hi,

usually in computer graphics Y is counted to increase downwards. I casn do it with: setworldcoordinates(0, 400, 600, 0)

but then, "right(..)" turns to the left :/

I could swap: right, left = left, right

but on errror I get a bit misleading message

...

...

...

right() Traceback (most recent call last): File "<pyshell#10>", line 1, in <module> right() TypeError: left() takes exactly 1 argument (0 given)

I thought to make this hack for kids, so better clearer error msgs...

Any Ideas?

http://bugs.python.org/issue23660 <http://bugs.python.org/issue23660> (includes a proposed "permanent" fix).

André

Thanks :) -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt <http://galvosukykla.lt/> _______________________________________________ Edu-sig mailing list Edu-sig@python.org <mailto:Edu-sig@python.org> https://mail.python.org/mailman/listinfo/edu-sig <https://mail.python.org/mailman/listinfo/edu-sig>

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Dear Andre, Thank you. The issue is reopened. If others would like to test your recommended fix still applies cleanly, I will be happy to review it. Warmly, Carol

On Jun 18, 2018, at 9:18 AM, Andre Roberge <andre.roberge@gmail.com <mailto:andre.roberge@gmail.com>> wrote:

Dear Carol,

I apologize for letting my frustration show in this way, in a public forum.

André

On Mon, Jun 18, 2018 at 1:01 PM Carol Willing <willingc@willingconsulting.com <mailto:willingc@willingconsulting.com>> wrote: Hi Andre,

I'm sorry that you did not like my response when I was triaging all of the open Turtle issues.

I am happy to change the status back to open. All that you needed to do was ask politely and give me a chance, as a volunteer, to have the time to do so.

Regards,

Carol

...

On Jun 17, 2018, at 1:41 PM, Andre Roberge <andre.roberge@gmail.com <mailto:andre.roberge@gmail.com>> wrote:

So, a little over 3 years after I submitted a bug report (see previous conversation below) **with a fix** so that no one would have to explain why "right()" could result in a turtle turning left, and vice-versa, my submission was refused and the bug report was closed with the following explanation:

" I'm closing this issue since introducing this suggested change would impact teaching materials and resources that have already been published. This would be a change that would break compatibility. " I'm curious: does anyone on the edu-sig list has written teaching material for the turtle module that sets world coordinates such that left and right are reversed? If so, how do you explain it to students?

Rant: This is the third time that I submit either a bug report for cPython **with** a proposed fix, or simply a fix for an existing bug report and that it is either rejected or dismissed with no alternative solution proposed. Thankfully, the folks here on edu-sig have been much more supportive since I joined, almost 15 years ago. /rant

André

On Fri, Mar 13, 2015 at 12:48 PM Andre Roberge <andre.roberge@gmail.com <mailto:andre.roberge@gmail.com>> wrote:

On Fri, Mar 13, 2015 at 8:52 AM, Jurgis Pralgauskis <jurgis.pralgauskis@gmail.com <mailto:jurgis.pralgauskis@gmail.com>> wrote: Hi,

usually in computer graphics Y is counted to increase downwards. I casn do it with: setworldcoordinates(0, 400, 600, 0)

but then, "right(..)" turns to the left :/

I could swap: right, left = left, right

but on errror I get a bit misleading message

...

...

...

right() Traceback (most recent call last): File "<pyshell#10>", line 1, in <module> right() TypeError: left() takes exactly 1 argument (0 given)

I thought to make this hack for kids, so better clearer error msgs...

Any Ideas?

http://bugs.python.org/issue23660 <http://bugs.python.org/issue23660> (includes a proposed "permanent" fix).

André

Thanks :) -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt <http://galvosukykla.lt/> _______________________________________________ Edu-sig mailing list Edu-sig@python.org <mailto:Edu-sig@python.org> https://mail.python.org/mailman/listinfo/edu-sig <https://mail.python.org/mailman/listinfo/edu-sig>

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On Mon, Jun 18, 2018 at 1:50 PM Jurgis Pralgauskis < jurgis.pralgauskis@gmail.com> wrote:

Ok, I could test it :)

Should I wait for some commit and comment results on the issues site or how...?

​Jurgis: Could you just apply the patch I submitted locally and test it? Or would anyone else volunteer to test it? Obviously, I can provide an independent test of my own contribution. :-)​

-- Jurgis Pralgauskis tel: 8-616 77613

2018-06-18, pr 19:32, Carol Willing <willingc@willingconsulting.com> rašė:

...

Dear Andre,

Thank you.

The issue is reopened. If others would like to test your recommended fix still applies cleanly, I will be happy to review it.

Warmly,

Carol

On Jun 18, 2018, at 9:18 AM, Andre Roberge <andre.roberge@gmail.com> wrote:

Dear Carol,

I apologize for letting my frustration show in this way, in a public forum.

André

On Mon, Jun 18, 2018 at 1:01 PM Carol Willing < willingc@willingconsulting.com> wrote:

...

Hi Andre,

I'm sorry that you did not like my response when I was triaging all of the open Turtle issues.

I am happy to change the status back to open. All that you needed to do was ask politely and give me a chance, as a volunteer, to have the time to do so.

Regards,

Carol

On Jun 17, 2018, at 1:41 PM, Andre Roberge <andre.roberge@gmail.com> wrote:

So, a little over 3 years after I submitted a bug report (see previous conversation below) **with a fix** so that no one would have to explain why "right()" could result in a turtle turning left, and vice-versa, my submission was refused and the bug report was closed with the following explanation:

"

I'm closing this issue since introducing this suggested change would impact teaching materials and resources that have already been published. This would be a change that would break compatibility.

"

I'm curious: does anyone on the edu-sig list has written teaching material for the turtle module that sets world coordinates such that left and right are reversed? If so, how do you explain it to students?

Rant: This is the third time that I submit either a bug report for cPython **with** a proposed fix, or simply a fix for an existing bug report and that it is either rejected or dismissed with no alternative solution proposed. Thankfully, the folks here on edu-sig have been much more supportive since I joined, almost 15 years ago. /rant

André

On Fri, Mar 13, 2015 at 12:48 PM Andre Roberge <andre.roberge@gmail.com> wrote:

...

On Fri, Mar 13, 2015 at 8:52 AM, Jurgis Pralgauskis < jurgis.pralgauskis@gmail.com> wrote:

...

Hi,

usually in computer graphics Y is counted to increase downwards. I casn do it with: setworldcoordinates(0, 400, 600, 0)

but then, "right(..)" turns to the left :/

I could swap: right, left = left, right

but on errror I get a bit misleading message

...

>> right() Traceback (most recent call last): File "<pyshell#10>", line 1, in <module> right() TypeError: left() takes exactly 1 argument (0 given)

I thought to make this hack for kids, so better clearer error msgs...

...

Any Ideas?

http://bugs.python.org/issue23660 (includes a proposed "permanent" fix).

André

...

Thanks :) -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

_______________________________________________ Edu-sig mailing list Edu-sig@python.org https://mail.python.org/mailman/listinfo/edu-sig

_______________________________________________

Edu-sig mailing list Edu-sig@python.org https://mail.python.org/mailman/listinfo/edu-sig

_______________________________________________ Edu-sig mailing list Edu-sig@python.org https://mail.python.org/mailman/listinfo/edu-sig

Sticking my nose in where it don't belong. ;-) But that's never stopped me before. ;-) First "I are not a teacher". At least, not in any formal sense of the word. Second, some would say "I are not a programmer". I don't listen to those people. In spite of the common "in computer graphics Y goes down", does that make sense to new learners? I've gotten used to various coordinate systems, but the first time I had to work with graph paper and plotting (and, for that matter, maps) one goes "up" ("north", "forward") for Y. Then again, maybe the average learner isn't quite as flexible these days, and telling them after they've gotten used to a system that they have to flip everything upside down and backwards isn't a great idea. I attribute my own flexibility not to any innate ability but rather to learning during a time when architectures OS's and languages were changing fast enough that there wasn't time to become set in one's ways. ​[Note: Grammatical "mistakes" above are meant as weak -- very weak -- humor. At least, most are.]​ -- *Kevin Cole* <http://novawebdevelopment.org> NOVA Web Development Co-Op http://novawebdevelopment.org/ Arlington, VA

I also stick my nose here. The notion of "in computer graphics Y goes down" is not as true as some people think. The graphics you are looking at right now on your computer most likely to have gone through some programs that use "Y goes up" scheme (such as GLSL). Only if you are talking about pixels and raster graphics, you could say that there is a dominant convention to make Y go down, but in with vectors, there is no such dominance. For end-users, why does it matter how actually pixels are stored in the actual memory? Computer is medium that can simulate anything; so the decision should not be based on what computer does at the lower levels. Once we leave from what computer does at low-level, there are math text books, which are dominantly "Y-up". Why do they have to know two different conventions? Unless, of course, learning the fact that the coordinate system is just a convention and can be different. Also there may be a case where the particular turtle graphics implementation is tied to the lower level pixel representation. But is basically mixing different abstraction levels, and unless you want to teach about mixing abstraction levels, it is a bad starting point. In summary: the statement "in computer graphics Y goes down" is a wrong argument for turtle graphics to use Y-down coordinate system. Then, for turtles and for end-users, there is an existing convention to make Y go down. So that should be a better default. On Mon, Jun 18, 2018 at 9:54 AM, Kevin Cole < kevin.cole@novawebdevelopment.org> wrote:

Sticking my nose in where it don't belong. ;-) But that's never stopped me before. ;-)

First "I are not a teacher". At least, not in any formal sense of the word. Second, some would say "I are not a programmer". I don't listen to those people.

In spite of the common "in computer graphics Y goes down", does that make sense to new learners? I've gotten used to various coordinate systems, but the first time I had to work with graph paper and plotting (and, for that matter, maps) one goes "up" ("north", "forward") for Y. Then again, maybe the average learner isn't quite as flexible these days, and telling them after they've gotten used to a system that they have to flip everything upside down and backwards isn't a great idea. I attribute my own flexibility not to any innate ability but rather to learning during a time when architectures OS's and languages were changing fast enough that there wasn't time to become set in one's ways.

​[Note: Grammatical "mistakes" above are meant as weak -- very weak -- humor. At least, most are.]​ -- *Kevin Cole* <http://novawebdevelopment.org> NOVA Web Development Co-Op http://novawebdevelopment.org/ Arlington, VA

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-- -- Yoshiki

On Tue, Jun 19, 2018 at 10:40 AM, Andre Roberge <andre.roberge@gmail.com> wrote:

HI,

There seems to be a lot of misunderstanding about this issue. Hopefully, the following can help clear it up.

0. The turtle module includes functions named left() and right() which result in the turtle rotating in the corresponding direction on the screen. 1. The turtle implementation includes a function, setworldcoordinates(), which allows one to have user-defined coordinates (both for the width and height of the world) including a choice as to which in which direction the coordinates are increasing. The issue has nothing to do with what choice is "best"; any user is free to use whatever they want. 2. In the current implementation, if one choses some particular orientation for the coordinates, the role of left() and right() are inverted and no longer correspond to what the user sees on the screen.

The submitted fix simply ensures that, no matter what one chooses for the world coordinates via setworldcoordinates, when right() is called in a program, the turtle turns right and not left.

Thank you for the clarification. I was just ranting about my pet peeve^^ Left and right should be consistent with the actual direction the turtle turns, from the POV of the turtle, yes. (Does it involve changing the "heading" of the turtle?)

André

On Tue, Jun 19, 2018 at 2:29 PM Yoshiki Ohshima <Yoshiki.Ohshima@acm.org> wrote:

...

I also stick my nose here.

The notion of "in computer graphics Y goes down" is not as true as some people think. The graphics you are looking at right now on your computer most likely to have gone through some programs that use "Y goes up" scheme (such as GLSL).

Only if you are talking about pixels and raster graphics, you could say that there is a dominant convention to make Y go down, but in with vectors, there is no such dominance.

For end-users, why does it matter how actually pixels are stored in the actual memory? Computer is medium that can simulate anything; so the decision should not be based on what computer does at the lower levels.

Once we leave from what computer does at low-level, there are math text books, which are dominantly "Y-up". Why do they have to know two different conventions? Unless, of course, learning the fact that the coordinate system is just a convention and can be different.

Also there may be a case where the particular turtle graphics implementation is tied to the lower level pixel representation. But is basically mixing different abstraction levels, and unless you want to teach about mixing abstraction levels, it is a bad starting point.

In summary: the statement "in computer graphics Y goes down" is a wrong argument for turtle graphics to use Y-down coordinate system. Then, for turtles and for end-users, there is an existing convention to make Y go down. So that should be a better default.

On Mon, Jun 18, 2018 at 9:54 AM, Kevin Cole <kevin.cole@ novawebdevelopment.org> wrote:

...

Sticking my nose in where it don't belong. ;-) But that's never stopped me before. ;-)

First "I are not a teacher". At least, not in any formal sense of the word. Second, some would say "I are not a programmer". I don't listen to those people.

In spite of the common "in computer graphics Y goes down", does that make sense to new learners? I've gotten used to various coordinate systems, but the first time I had to work with graph paper and plotting (and, for that matter, maps) one goes "up" ("north", "forward") for Y. Then again, maybe the average learner isn't quite as flexible these days, and telling them after they've gotten used to a system that they have to flip everything upside down and backwards isn't a great idea. I attribute my own flexibility not to any innate ability but rather to learning during a time when architectures OS's and languages were changing fast enough that there wasn't time to become set in one's ways.

​[Note: Grammatical "mistakes" above are meant as weak -- very weak -- humor. At least, most are.]​ -- *Kevin Cole* <http://novawebdevelopment.org> NOVA Web Development Co-Op http://novawebdevelopment.org/ Arlington, VA

_______________________________________________ Edu-sig mailing list Edu-sig@python.org https://mail.python.org/mailman/listinfo/edu-sig

-- -- Yoshiki

_______________________________________________ Edu-sig mailing list Edu-sig@python.org https://mail.python.org/mailman/listinfo/edu-sig

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-- -- Yoshiki

Is this Python's edu-sig or Monty Python's philosophers club? ;-) ;-) ;-) Anyone on this list could probably do the following in less than one minute... Run the following program, showing how left() results in a proper turn left

...

...

from turtle import * forward(40) left(90) forward(40)

Now, close the interpreter and run it again, this time with the following

...

...

from turtle import * setworldcoordinates(-100, 100, 100, -100) forward(40) left(90) forward(40)

See how left() no longer correspond to a left() turn for the turtle? André ===== For those reading this on a device that does not have Python installed, below, I show an ascii-simulated representation of forward(100) right(90) forward(100) when the turtle is oriented facing left initially, starting at the position labeled by O and ending at X (example chosen because it is the easiest for me to draw, regardless of whether a proportional font is used or not for this email) X | | | | | ---------------O In the current implementation, with a particular choice for user-defined coordinates , the same instructions might yield the following ----------------O | | | | | X i.e. a right() instruction would result in a left turn, and vice-versa. On Tue, Jun 19, 2018 at 3:01 PM Kevin Cole < kevin.cole@novawebdevelopment.org> wrote:

On Tue, Jun 19, 2018 at 1:40 PM, Andre Roberge <andre.roberge@gmail.com> wrote:

...

HI,

There seems to be a lot of misunderstanding about this issue. Hopefully, the following can help clear it up.

0. The turtle module includes functions named left() and right() which result in the turtle rotating in the corresponding direction on the screen. 1. The turtle implementation includes a function, setworldcoordinates(), which allows one to have user-defined coordinates (both for the width and height of the world) including a choice as to which in which direction the coordinates are increasing. The issue has nothing to do with what choice is "best"; any user is free to use whatever they want. 2. In the current implementation, if one choses some particular orientation for the coordinates, the role of left() and right() are inverted and no longer correspond to what the user sees on the screen.

The submitted fix simply ensures that, no matter what one chooses for the world coordinates via setworldcoordinates, when right() is called in a program, the turtle turns right and not left.

André

​Ah. Then I did indeed misunderstand the point. And now I'm of two minds as to whether or not the fix is a fix. I see it as an option, but I also see the argument that sprites, avatars, turtles, etc, often are designed with a "head" and a "tail". So, it's back to the whole "stage left" vs. "left" argument: Are we talking about the virtual creature's left or the viewer's left? (Or am I misunderstanding yet again? If I'm not misunderstanding, I would say "Make it a configuration or startup option, or attribute of setworldcoordinates, or some such." For me, if I'm giving you directions to my apartment, and say in e-mail "Turn left" I would expect you to turn to your left, even if you knew which direction I was currently facing. I would expect an avatar to turn to its left regardless of my viewing angle.)​

-- *Kevin Cole* <http://novawebdevelopment.org> NOVA Web Development Co-Op http://novawebdevelopment.org/ Arlington, VA

...

performs as expected out of the box right?

​Yes, it does. BUT, if you set the world coordinates like Jurgis reported, then left and right are inverted. There's an easy fix ... but it has been rejected.​

​OK. Thanks for the clarification. I had no idea. Kirby