Smalltalk › Squeak › Squeak VM

Re: [Pharo-project] About ~= and ~~

_‹ Previous Topic Next Topic _›

Classic

List

Threaded

22 messages Options

Eliot Miranda-2

Re: [Pharo-project] About ~= and ~~

On Wed, Oct 12, 2011 at 8:38 AM, Levente Uzonyi <[hidden email]> wrote:

On Wed, 12 Oct 2011, Clara Allende wrote:

Hi guys,

I'm wondering, why?

ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

self == anObject
ifTrue: [^ false]
ifFalse: [^ true]

Instead of:
ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

^(self == anObject) not

And why?
Object >> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^self = anObject == false

Instead of
Object>> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^(self = anObject) not.

Is there any particular reason for this that I'm missing?

Performance.

But better still is to add a ~~ primitive. I did this for VisualWorks. e.g. primitive 150 is free. why don't we use that for 1.4/4.3?

Levente

Thanks in advance!
--

"*Most good programmers do programming not because they expect to get paid
or get adulation by the public, but because it is fun to program.*"

Linus Torvalds

--
best,

Eliot

Mariano Martinez Peck

Re: [Pharo-project] About ~= and ~~

On Wed, Oct 12, 2011 at 6:44 PM, Eliot Miranda <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 8:38 AM, Levente Uzonyi <[hidden email]> wrote:

On Wed, 12 Oct 2011, Clara Allende wrote:

Hi guys,

I'm wondering, why?

ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

self == anObject
ifTrue: [^ false]
ifFalse: [^ true]

Instead of:
ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

^(self == anObject) not

And why?
Object >> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^self = anObject == false

Instead of
Object>> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^(self = anObject) not.

Is there any particular reason for this that I'm missing?

Performance.

But better still is to add a ~~ primitive. I did this for VisualWorks. e.g. primitive 150 is free. why don't we use that for 1.4/4.3?

with or without special bytecode associated?

Levente

Thanks in advance!
--

"*Most good programmers do programming not because they expect to get paid
or get adulation by the public, but because it is fun to program.*"

Linus Torvalds

--
best,
Eliot

--
Mariano
http://marianopeck.wordpress.com

Eliot Miranda-2

Re: [Pharo-project] About ~= and ~~

On Wed, Oct 12, 2011 at 10:26 AM, Mariano Martinez Peck <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 6:44 PM, Eliot Miranda <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 8:38 AM, Levente Uzonyi <[hidden email]> wrote:

On Wed, 12 Oct 2011, Clara Allende wrote:

Hi guys,

I'm wondering, why?

ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

self == anObject
ifTrue: [^ false]
ifFalse: [^ true]

Instead of:
ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

^(self == anObject) not

And why?
Object >> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^self = anObject == false

Instead of
Object>> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^(self = anObject) not.

Is there any particular reason for this that I'm missing?

Performance.

But better still is to add a ~~ primitive. I did this for VisualWorks. e.g. primitive 150 is free. why don't we use that for 1.4/4.3?

with or without special bytecode associated?

Initially without. Dynamic frequency is low, and primitive adds significant performance over the non-primitive version. One could use the blockCopy: special bytecode but I'd wait until doing a complete bytecode set redesign.

Levente

Thanks in advance!
--

"*Most good programmers do programming not because they expect to get paid
or get adulation by the public, but because it is fun to program.*"

Linus Torvalds

--
best,
Eliot

--
Mariano
http://marianopeck.wordpress.com

--
best,

Eliot

Mariano Martinez Peck

Re: [Pharo-project] About ~= and ~~

On Wed, Oct 12, 2011 at 7:29 PM, Eliot Miranda <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 10:26 AM, Mariano Martinez Peck <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 6:44 PM, Eliot Miranda <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 8:38 AM, Levente Uzonyi <[hidden email]> wrote:

On Wed, 12 Oct 2011, Clara Allende wrote:

Hi guys,

I'm wondering, why?

ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

self == anObject
ifTrue: [^ false]
ifFalse: [^ true]

Instead of:
ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

^(self == anObject) not

And why?
Object >> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^self = anObject == false

Instead of
Object>> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^(self = anObject) not.

Is there any particular reason for this that I'm missing?

Performance.

But better still is to add a ~~ primitive. I did this for VisualWorks. e.g. primitive 150 is free. why don't we use that for 1.4/4.3?

with or without special bytecode associated?

Initially without.

Dynamic frequency is low, and primitive adds significant performance over the non-primitive version. One could use the blockCopy: special bytecode but I'd wait until doing a complete bytecode set redesign.

Levente

Thanks in advance!
--

"*Most good programmers do programming not because they expect to get paid
or get adulation by the public, but because it is fun to program.*"

Linus Torvalds

--
best,
Eliot

--
Mariano
http://marianopeck.wordpress.com

--
best,
Eliot

--
Mariano
http://marianopeck.wordpress.com

Eliot Miranda-2

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

OK, in the end I decided on primitive number 169. It doesn't waste the 150-159 range and is in amongst primitiveAdoptInstance and primitiveSetIdentityHash. David, would you like to integrate this into the main branch?

On Wed, Oct 12, 2011 at 10:47 AM, Mariano Martinez Peck <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 7:29 PM, Eliot Miranda <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 10:26 AM, Mariano Martinez Peck <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 6:44 PM, Eliot Miranda <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 8:38 AM, Levente Uzonyi <[hidden email]> wrote:

On Wed, 12 Oct 2011, Clara Allende wrote:

Hi guys,

I'm wondering, why?

ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

self == anObject
ifTrue: [^ false]
ifFalse: [^ true]

Instead of:
ProtoObject>> ~~ anObject
"Answer whether the receiver and the argument are not the same object
(do not have the same object pointer)."

^(self == anObject) not

And why?
Object >> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^self = anObject == false

Instead of
Object>> ~= anObject
"Answer whether the receiver and the argument do not represent the
same object."

^(self = anObject) not.

Is there any particular reason for this that I'm missing?

Performance.

But better still is to add a ~~ primitive. I did this for VisualWorks. e.g. primitive 150 is free. why don't we use that for 1.4/4.3?

with or without special bytecode associated?

Initially without.

+1

Dynamic frequency is low, and primitive adds significant performance over the non-primitive version. One could use the blockCopy: special bytecode but I'd wait until doing a complete bytecode set redesign.

Levente

Thanks in advance!
--

"*Most good programmers do programming not because they expect to get paid
or get adulation by the public, but because it is fun to program.*"

Linus Torvalds

--
best,
Eliot

--
Mariano
http://marianopeck.wordpress.com

--
best,
Eliot

--
Mariano
http://marianopeck.wordpress.com

--
best,

Eliot

primitiveNotIdentical.st (43K) Download Attachment

Colin Putney-3

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

On Wed, Oct 12, 2011 at 11:25 AM, Eliot Miranda <[hidden email]> wrote:
> OK, in the end I decided on primitive number 169. It doesn't waste the
> 150-159 range and is in amongst primitiveAdoptInstance and
> primitiveSetIdentityHash. David, would you like to integrate this into the
> main branch?

If dynamic frequency is low, why does it need to be a primitive?

Colin

Igor Stasenko

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

On 12 October 2011 21:22, Colin Putney <[hidden email]> wrote:
>
> On Wed, Oct 12, 2011 at 11:25 AM, Eliot Miranda <[hidden email]> wrote:
>> OK, in the end I decided on primitive number 169. It doesn't waste the
>> 150-159 range and is in amongst primitiveAdoptInstance and
>> primitiveSetIdentityHash. David, would you like to integrate this into the
>> main branch?
>
> If dynamic frequency is low, why does it need to be a primitive?
>
+1

i dont see a need for add a primitive.

> Colin
>

--
Best regards,
Igor Stasenko.

Eliot Miranda-2

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

In reply to this post by Colin Putney-3

On Wed, Oct 12, 2011 at 12:22 PM, Colin Putney <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 11:25 AM, Eliot Miranda <[hidden email]> wrote:
> OK, in the end I decided on primitive number 169. It doesn't waste the
> 150-159 range and is in amongst primitiveAdoptInstance and
> primitiveSetIdentityHash. David, would you like to integrate this into the
> main branch?

If dynamic frequency is low, why does it need to be a primitive?

People avoid it because of performance. But I much prefer foo ~~ bar ifTrue: than foo == bar ifFalse:. So I suspect/hope dynamic frequency will grow as people find its not such a performance issue any more.

Colin

--
best,

Eliot

Colin Putney-3

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

On Wed, Oct 12, 2011 at 1:16 PM, Eliot Miranda <[hidden email]> wrote:
> People avoid it because of performance. But I much prefer foo ~~ bar ifTrue: than foo == bar ifFalse:. So I suspect/hope dynamic frequency will grow as people find its not such a performance issue any more.

Well, no accounting for taste, I guess. I'd avoid it because I much
prefer foo == bar iFalse:

Colin

Eliot Miranda-2

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

On Wed, Oct 12, 2011 at 1:19 PM, Colin Putney <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 1:16 PM, Eliot Miranda <[hidden email]> wrote:
> People avoid it because of performance. But I much prefer foo ~~ bar ifTrue: than foo == bar ifFalse:. So I suspect/hope dynamic frequency will grow as people find its not such a performance issue any more.

Well, no accounting for taste, I guess. I'd avoid it because I much
prefer foo == bar iFalse:

But why, if it doesn't express intent directly? It's cognitively more difficult. You have to negate to get the intent.

Colin

--
best,

Eliot

David Ungar

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

Maybe we need an if: isAnother: method in Object....

foo if: bar isAnother: [...]

:)

- David (from iPad, typos likely)

On Oct 12, 2011, at 1:20 PM, Eliot Miranda <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 1:19 PM, Colin Putney <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 1:16 PM, Eliot Miranda <[hidden email]> wrote:
> People avoid it because of performance. But I much prefer foo ~~ bar ifTrue: than foo == bar ifFalse:. So I suspect/hope dynamic frequency will grow as people find its not such a performance issue any more.

Well, no accounting for taste, I guess. I'd avoid it because I much
prefer foo == bar iFalse:

But why, if it doesn't express intent directly? It's cognitively more difficult. You have to negate to get the intent.

Colin

--
best,
Eliot

Colin Putney-3

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

In reply to this post by Eliot Miranda-2

On Wed, Oct 12, 2011 at 1:20 PM, Eliot Miranda <[hidden email]> wrote:

> But why, if it doesn't express intent directly? It's cognitively more difficult. You have to negate to get the intent.

<shrug> to me it's not cognitively more difficult. You have to negate
either way, either "not identical" or "if false". I just prefer the
negation to be explicit in the big "ifFalse:" rather than implied by
the implementation of #~~.

Colin

Nicolas Cellier

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

2011/10/12 Colin Putney <[hidden email]>:

>
> On Wed, Oct 12, 2011 at 1:20 PM, Eliot Miranda <[hidden email]> wrote:
>
>> But why, if it doesn't express intent directly? It's cognitively more difficult. You have to negate to get the intent.
>
> <shrug> to me it's not cognitively more difficult. You have to negate
> either way, either "not identical" or "if false". I just prefer the
> negation to be explicit in the big "ifFalse:" rather than implied by
> the implementation of #~~.
>
> Colin
>

One of my favourites in the serie is #quo: which found currently
fastest way to inline #xor:

ng := self negative == aNumber negative == false.

Nicolas

Andreas.Raab

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

In reply to this post by Eliot Miranda-2

On 10/12/2011 22:20, Eliot Miranda wrote:

On Wed, Oct 12, 2011 at 1:19 PM, Colin Putney <[hidden email]> wrote:

On Wed, Oct 12, 2011 at 1:16 PM, Eliot Miranda <[hidden email]> wrote:
> People avoid it because of performance. But I much prefer foo ~~ bar ifTrue: than foo == bar ifFalse:. So I suspect/hope dynamic frequency will grow as people find its not such a performance issue any more.

Well, no accounting for taste, I guess. I'd avoid it because I much
prefer foo == bar iFalse:

But why, if it doesn't express intent directly? It's cognitively more difficult. You have to negate to get the intent.

It's really the same either way. My main reason for disliking ~= and ~~ is that both of these are aesthetically unpleasing. I'd much rather see <> instead of ~= and perhaps <==> instead of ~~.

Cheers,
- Andreas

Bert Freudenberg

Re: [squeak-dev] [Vm-dev] Re: [Pharo-project] About ~= and ~~

In reply to this post by Colin Putney-3

On 12.10.2011, at 22:28, Colin Putney wrote:

> On Wed, Oct 12, 2011 at 1:20 PM, Eliot Miranda <[hidden email]> wrote:
>
>> But why, if it doesn't express intent directly? It's cognitively more difficult. You have to negate to get the intent.
>
> <shrug> to me it's not cognitively more difficult. You have to negate
> either way, either "not identical" or "if false". I just prefer the
> negation to be explicit in the big "ifFalse:" rather than implied by
> the implementation of #~~.
>
> Colin

Can't really say why but I also prefer "foo == bar ifFalse:" over "foo ~~ bar ifTrue:". And I don't think performance has anything to do with it. To me, "==" just seems ... simpler?

- Bert -

Nicolas Cellier

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

In reply to this post by Andreas.Raab

2011/10/13 Andreas Raab <[hidden email]>:

>
> On 10/12/2011 22:20, Eliot Miranda wrote:
>
> On Wed, Oct 12, 2011 at 1:19 PM, Colin Putney <[hidden email]> wrote:
>>
>> On Wed, Oct 12, 2011 at 1:16 PM, Eliot Miranda <[hidden email]> wrote:
>> > People avoid it because of performance. But I much prefer foo ~~ bar ifTrue: than foo == bar ifFalse:. So I suspect/hope dynamic frequency will grow as people find its not such a performance issue any more.
>>
>> Well, no accounting for taste, I guess. I'd avoid it because I much
>> prefer foo == bar iFalse:
>
> But why, if it doesn't express intent directly? It's cognitively more difficult. You have to negate to get the intent.
>
> It's really the same either way. My main reason for disliking ~= and ~~ is that both of these are aesthetically unpleasing. I'd much rather see <> instead of ~= and perhaps <==> instead of ~~.
>

Yes, one could think that ~= is approximately equal...
Though the operator means different in Matlab too.

<> exists in some languages too (Ada ? Fortran 95).
But I dislike <==>
<<>> or <><> or =<>= are not better...

I like =/= but that makes a single selector...
=//= ?

Unless we start using what unicode provides (Fortress).

Nicolas

> Cheers,
> - Andreas
>
>
>

Nicolas Cellier

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

2011/10/13 Nicolas Cellier <[hidden email]>:

> 2011/10/13 Andreas Raab <[hidden email]>:
>>
>> On 10/12/2011 22:20, Eliot Miranda wrote:
>>
>> On Wed, Oct 12, 2011 at 1:19 PM, Colin Putney <[hidden email]> wrote:
>>>
>>> On Wed, Oct 12, 2011 at 1:16 PM, Eliot Miranda <[hidden email]> wrote:
>>> > People avoid it because of performance. But I much prefer foo ~~ bar ifTrue: than foo == bar ifFalse:. So I suspect/hope dynamic frequency will grow as people find its not such a performance issue any more.
>>>
>>> Well, no accounting for taste, I guess. I'd avoid it because I much
>>> prefer foo == bar iFalse:
>>
>> But why, if it doesn't express intent directly? It's cognitively more difficult. You have to negate to get the intent.
>>
>> It's really the same either way. My main reason for disliking ~= and ~~ is that both of these are aesthetically unpleasing. I'd much rather see <> instead of ~= and perhaps <==> instead of ~~.
>>
>
> Yes, one could think that ~= is approximately equal...
> Though the operator means different in Matlab too.
>
> <> exists in some languages too (Ada ? Fortran 95).

Ah no, it is /=
<> was in Matrix-x Xmath for example...

> But I dislike <==>
> <<>> or <><> or =<>= are not better...
>
> I like =/= but that makes a single selector...
> =//= ?
>
> Unless we start using what unicode provides (Fortress).
>
> Nicolas
>
>> Cheers,
>> - Andreas
>>
>>
>>
>

David T. Lewis

Re: [squeak-dev] Re: [Vm-dev] Re: [Pharo-project] About ~= and ~~

In reply to this post by Eliot Miranda-2

On Wed, Oct 12, 2011 at 11:25:32AM -0700, Eliot Miranda wrote:
> OK, in the end I decided on primitive number 169. It doesn't waste the
> 150-159 range and is in amongst primitiveAdoptInstance and
> primitiveSetIdentityHash. David, would you like to integrate this into the
> main branch?

Aside from preferences concerning use of #~~ is there any serious objection
to adding the primitive itself? I can think of no reason not to do so,
and have added it to the main branch on that basis. If anyone can think
of a good reason that it should not be there, I'll remove it.

Dave

laza

Re: [squeak-dev] [Vm-dev] Re: [Pharo-project] About ~= and ~~

In reply to this post by Bert Freudenberg

2011/10/13 Bert Freudenberg <[hidden email]>

To me, "==" just seems ... simpler?

If one presumes that most got early on introduced to = as a symbol for equality (and ≠ for unequality and not ~), this shouldn't be too surprising?

Alex

Nicolas Cellier

Re: [squeak-dev] [Vm-dev] Re: [Pharo-project] About ~= and ~~

2011/10/18 Alexander Lazarević <[hidden email]>:

>
> 2011/10/13 Bert Freudenberg <[hidden email]>
>>
>> To me, "==" just seems ... simpler?
>
> If one presumes that most got early on introduced to = as a symbol for equality (and ≠ for unequality and not ~), this shouldn't be too surprising?
>
> Alex
>
>

Well, is ~ interpretation ubiquitous ? I rather learned ¬ NOT SIGN.
http://en.wikipedia.org/wiki/Logical_not

And if ≠ is translated /= in ASCII (FORTRAN 95 & ADA)
Then by analogy ~= could ambiguously mean ≃ ASYMPOTICALLY EQUAL TO and
~~ mean ≈ ALMOST EQUAL TO unless it is ≅ APPROXIMATELY EQUAL TO .

Nicolas