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Reverse interval

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kilon.alios

Reverse interval

hey guys I try to do a reverse interval like this

tp := 0.0.

(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].

tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

EstebanLM

Re: Reverse interval

this is correct behaviour (since 0.50 + 0.01 will be bigger than 0.01),

correct way to define this step is:

(0.50 to: 0.01 by: -0.01) do:[ :each| tp := tp + each ].

(by: -0.01), negative

Esteban

On 5 Jan 2017, at 09:15, Dimitris Chloupis <[hidden email]> wrote:

hey guys I try to do a reverse interval like this

tp := 0.0.
(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].
tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

kilon.alios

Re: Reverse interval

cant say it makes sense for me , why it assumes I want to +0.01 when I give 0.5 to 0.01 when it should assume I want to -0.01 ? is there a scenario that would not be true ?

in any case its better than reversedo , thank you

On Thu, Jan 5, 2017 at 10:20 AM Esteban Lorenzano <[hidden email]> wrote:

this is correct behaviour (since 0.50 + 0.01 will be bigger than 0.01),
correct way to define this step is:

(0.50 to: 0.01 by: -0.01) do:[ :each| tp := tp + each ].

(by: -0.01), negative

Esteban

On 5 Jan 2017, at 09:15, Dimitris Chloupis <[hidden email]> wrote:

hey guys I try to do a reverse interval like this

tp := 0.0.
(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].
tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

jtuchel

Re: Reverse interval

Well, it makes sense if you think of the implementation of to:by:do: as a loop.
How would you implement the stop condition? Does every case where start>stop mean you want to walk backwards?

Joachim

Am 05.01.17 um 09:29 schrieb Dimitris Chloupis:

cant say it makes sense for me , why it assumes I want to +0.01 when I give 0.5 to 0.01 when it should assume I want to -0.01 ? is there a scenario that would not be true ?

in any case its better than reversedo , thank you

On Thu, Jan 5, 2017 at 10:20 AM Esteban Lorenzano <[hidden email]> wrote:

this is correct behaviour (since 0.50 + 0.01 will be bigger than 0.01),
correct way to define this step is:

(0.50 to: 0.01 by: -0.01) do:[ :each| tp := tp + each ].

(by: -0.01), negative

Esteban

On 5 Jan 2017, at 09:15, Dimitris Chloupis <[hidden email]> wrote:

hey guys I try to do a reverse interval like this

tp := 0.0.

(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].

tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

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Objektfabrik Joachim Tuchel          [hidden email]
Fliederweg 1                         http://www.objektfabrik.de
D-71640 Ludwigsburg                  http://joachimtuchel.wordpress.com
Telefon: +49 7141 56 10 86 0         Fax: +49 7141 56 10 86 1

EstebanLM

Re: Reverse interval

In reply to this post by kilon.alios

On 5 Jan 2017, at 09:29, Dimitris Chloupis <[hidden email]> wrote:

cant say it makes sense for me , why it assumes I want to +0.01 when I give 0.5 to 0.01 when it should assume I want to -0.01 ? is there a scenario that would not be true ?

take it this way: in C you’ll need to write:

for (int i = 0.50; i >= 0.1; i-=0.01) …

which is also explicit about the decreasing “i”… so I don’t understand why it does not makes sense for you :)

Esteban

in any case its better than reversedo , thank you

On Thu, Jan 5, 2017 at 10:20 AM Esteban Lorenzano <[hidden email]> wrote:
this is correct behaviour (since 0.50 + 0.01 will be bigger than 0.01),
correct way to define this step is:

(0.50 to: 0.01 by: -0.01) do:[ :each| tp := tp + each ].

(by: -0.01), negative

Esteban

On 5 Jan 2017, at 09:15, Dimitris Chloupis <[hidden email]> wrote:

hey guys I try to do a reverse interval like this

tp := 0.0.
(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].
tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

kilon.alios

Re: Reverse interval

mainly because in my 30 years of coding for fun I never gave a damn what C or other languages try to convince us what expected behaviour is , its one of the big reason why I code in Smalltalk ;)

plus I hate C/C++ with a vengeance , so :D

On Thu, Jan 5, 2017 at 10:38 AM Esteban Lorenzano <[hidden email]> wrote:

On 5 Jan 2017, at 09:29, Dimitris Chloupis <[hidden email]> wrote:

cant say it makes sense for me , why it assumes I want to +0.01 when I give 0.5 to 0.01 when it should assume I want to -0.01 ? is there a scenario that would not be true ?

take it this way: in C you’ll need to write:

for (int i = 0.50; i >= 0.1; i-=0.01) …

which is also explicit about the decreasing “i”… so I don’t understand why it does not makes sense for you :)

Esteban

in any case its better than reversedo , thank you

On Thu, Jan 5, 2017 at 10:20 AM Esteban Lorenzano <[hidden email]> wrote:
this is correct behaviour (since 0.50 + 0.01 will be bigger than 0.01),
correct way to define this step is:

(0.50 to: 0.01 by: -0.01) do:[ :each| tp := tp + each ].

(by: -0.01), negative

Esteban

On 5 Jan 2017, at 09:15, Dimitris Chloupis <[hidden email]> wrote:

hey guys I try to do a reverse interval like this

tp := 0.0.
(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].
tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

Nicolai Hess-3-2

Re: Reverse interval

2017-01-05 9:46 GMT+01:00 Dimitris Chloupis <[hidden email]>:

mainly because in my 30 years of coding for fun I never gave a damn what C or other languages try to convince us what expected behaviour is , its one of the big reason why I code in Smalltalk ;)

plus I hate C/C++ with a vengeance , so :D

On Thu, Jan 5, 2017 at 10:38 AM Esteban Lorenzano <[hidden email]> wrote:
On 5 Jan 2017, at 09:29, Dimitris Chloupis <[hidden email]> wrote:

cant say it makes sense for me , why it assumes I want to +0.01 when I give 0.5 to 0.01 when it should assume I want to -0.01 ? is there a scenario that would not be true ?

We often use (1 to: 0) for an "empty" interval. All this code wouldn't work if we would take this as a reversed (0 to: 1) interval.

take it this way: in C you’ll need to write:

for (int i = 0.50; i >= 0.1; i-=0.01) …

which is also explicit about the decreasing “i”… so I don’t understand why it does not makes sense for you :)

Esteban

in any case its better than reversedo , thank you

On Thu, Jan 5, 2017 at 10:20 AM Esteban Lorenzano <[hidden email]> wrote:
this is correct behaviour (since 0.50 + 0.01 will be bigger than 0.01),
correct way to define this step is:

(0.50 to: 0.01 by: -0.01) do:[ :each| tp := tp + each ].

(by: -0.01), negative

Esteban

On 5 Jan 2017, at 09:15, Dimitris Chloupis <[hidden email]> wrote:

hey guys I try to do a reverse interval like this

tp := 0.0.
(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].
tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

kilon.alios

Re: Reverse interval

ok fair enough, I am not saying I am right and you are wrong, just wanted to understand the reasoning

Would it not "Interval empty" made more sense ? or is (1 to: 0) convenient in some way in your scenario ?

On Thu, Jan 5, 2017 at 10:59 AM Nicolai Hess <[hidden email]> wrote:

2017-01-05 9:46 GMT+01:00 Dimitris Chloupis <[hidden email]>:
mainly because in my 30 years of coding for fun I never gave a damn what C or other languages try to convince us what expected behaviour is , its one of the big reason why I code in Smalltalk ;)

plus I hate C/C++ with a vengeance , so :D

On Thu, Jan 5, 2017 at 10:38 AM Esteban Lorenzano <[hidden email]> wrote:
On 5 Jan 2017, at 09:29, Dimitris Chloupis <[hidden email]> wrote:

cant say it makes sense for me , why it assumes I want to +0.01 when I give 0.5 to 0.01 when it should assume I want to -0.01 ? is there a scenario that would not be true ?

We often use (1 to: 0) for an "empty" interval. All this code wouldn't work if we would take this as a reversed (0 to: 1) interval.

take it this way: in C you’ll need to write:

for (int i = 0.50; i >= 0.1; i-=0.01) …

which is also explicit about the decreasing “i”… so I don’t understand why it does not makes sense for you :)

Esteban

in any case its better than reversedo , thank you

On Thu, Jan 5, 2017 at 10:20 AM Esteban Lorenzano <[hidden email]> wrote:
this is correct behaviour (since 0.50 + 0.01 will be bigger than 0.01),
correct way to define this step is:

(0.50 to: 0.01 by: -0.01) do:[ :each| tp := tp + each ].

(by: -0.01), negative

Esteban

On 5 Jan 2017, at 09:15, Dimitris Chloupis <[hidden email]> wrote:

hey guys I try to do a reverse interval like this

tp := 0.0.
(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].
tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

Nicolas Passerini

Re: Reverse interval

2017-01-05 10:33 GMT+01:00 Dimitris Chloupis <[hidden email]>:

Would it not "Interval empty" made more sense ? or is (1 to: 0) convenient in some way in your scenario ?

Nicolai Hess-3-2

Re: Reverse interval

In reply to this post by kilon.alios

It is just something I often saw, I don't even know if this is by-design.

I think there are good arguments for both interpretations

2017-01-05 10:33 GMT+01:00 Dimitris Chloupis <[hidden email]>:

ok fair enough, I am not saying I am right and you are wrong, just wanted to understand the reasoning

Would it not "Interval empty" made more sense ? or is (1 to: 0) convenient in some way in your scenario ?

On Thu, Jan 5, 2017 at 10:59 AM Nicolai Hess <[hidden email]> wrote:
2017-01-05 9:46 GMT+01:00 Dimitris Chloupis <[hidden email]>:
mainly because in my 30 years of coding for fun I never gave a damn what C or other languages try to convince us what expected behaviour is , its one of the big reason why I code in Smalltalk ;)

plus I hate C/C++ with a vengeance , so :D

On Thu, Jan 5, 2017 at 10:38 AM Esteban Lorenzano <[hidden email]> wrote:
On 5 Jan 2017, at 09:29, Dimitris Chloupis <[hidden email]> wrote:

cant say it makes sense for me , why it assumes I want to +0.01 when I give 0.5 to 0.01 when it should assume I want to -0.01 ? is there a scenario that would not be true ?

We often use (1 to: 0) for an "empty" interval. All this code wouldn't work if we would take this as a reversed (0 to: 1) interval.

take it this way: in C you’ll need to write:

for (int i = 0.50; i >= 0.1; i-=0.01) …

which is also explicit about the decreasing “i”… so I don’t understand why it does not makes sense for you :)

Esteban

in any case its better than reversedo , thank you

On Thu, Jan 5, 2017 at 10:20 AM Esteban Lorenzano <[hidden email]> wrote:
this is correct behaviour (since 0.50 + 0.01 will be bigger than 0.01),
correct way to define this step is:

(0.50 to: 0.01 by: -0.01) do:[ :each| tp := tp + each ].

(by: -0.01), negative

Esteban

On 5 Jan 2017, at 09:15, Dimitris Chloupis <[hidden email]> wrote:

hey guys I try to do a reverse interval like this

tp := 0.0.
(0.50 to: 0.01 by: 0.01) do:[ :each| tp := tp + each ].
tp inspect.

and I get nothing , is this a bug or a feature ?

i see a reverse method but looks weird to go that way and not very smalltalky / pharoic

John Pfersich

Re: Reverse interval

In reply to this post by kilon.alios

I can see uses for C, but C++ just turns my stomachs, and has since 1986, when I first experienced it 😠.

Sent from my iPhone

> On Jan 5, 2017, at 00:46, Dimitris Chloupis <[hidden email]> wrote:
>
> plus I hate C/C++ with a vengeance , so :D