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Problem extending the Number class

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Manfred Kröhnert

Problem extending the Number class

Hi,

I am currently trying to get a program running on Amber Smalltalk
which involves doing calculations with Number objects.

To add the missing functionality to the Number class I am using the
"*MyPackage" protocol.
So far I have succeeded in adding methods such as bitAnd:, bitOr: and so on.

However, implementing the shift operators produced an interesting result.
The implementations are the following:

<< aNumber
<return Number(self) << aNumber>

>> aNumber
<return Number(self) >> aNumber>

and the following happens when evaluating them:

4 << 1
-> 8

4 >> 1
-> true

Any ideas on what could possibly go wrong with the >> implementation?

Best regards,

Manfred Kröhnert

Herby Vojčík

Re: Problem extending the Number class

M K wrote:

> Hi,
>
> I am currently trying to get a program running on Amber Smalltalk
> which involves doing calculations with Number objects.
>
> To add the missing functionality to the Number class I am using the
> "*MyPackage" protocol.
> So far I have succeeded in adding methods such as bitAnd:, bitOr: and so on.
>
> However, implementing the shift operators produced an interesting result.
> The implementations are the following:
>
> << aNumber
> <return Number(self)<< aNumber>
>
>>> aNumber
> <return Number(self)>> aNumber>
>
> and the following happens when evaluating them:
>
> 4<< 1
> -> 8
>
> 4>> 1
> -> true

It seems like premature ending of < ... > pragma.
If it is interpreted as '(<return Number(self)>) > aNumber' than it can
return true (I just don't know who swallowed the last '>'.

Just the hypothesis.

> Any ideas on what could possibly go wrong with the>> implementation?
>
> Best regards,
>
> Manfred Kröhnert

Herby

Nicolas Petton

Re: Problem extending the Number class

In reply to this post by Manfred Kröhnert

Hi!

Inside verbatim javascript, the ">" character is escaped, exactly like the "!" in the chunk format.

So, if you write "Number(self) >> aNumber" it will be compiled as Number(self) > aNumber".

Cheers,

Nico

On Apr 21, 2012, at 7:31 PM, M K wrote:

Hi,

I am currently trying to get a program running on Amber Smalltalk
which involves doing calculations with Number objects.

To add the missing functionality to the Number class I am using the
"*MyPackage" protocol.
So far I have succeeded in adding methods such as bitAnd:, bitOr: and so on.

However, implementing the shift operators produced an interesting result.
The implementations are the following:

<< aNumber
<return Number(self) << aNumber>

aNumber
<return Number(self) >> aNumber>

and the following happens when evaluating them:

4 << 1
-> 8

4 >> 1
-> true

Any ideas on what could possibly go wrong with the >> implementation?

Best regards,

Manfred Kröhnert

Nicolas Petton
http://www.nicolas-petton.fr

Manfred Kröhnert

Re: Problem extending the Number class

Hi Nico,

> Inside verbatim javascript, the ">" character is escaped, exactly like the
> "!" in the chunk format.
> So, if you write "Number(self) >> aNumber" it will be compiled as
> Number(self) > aNumber".

thanks for the explanation.
Any ideas on how to write this line so that it actually evaluates the
shift operator as left shift and not as comparison?

Best,

Manfred

Nicolas Petton

Re: Problem extending the Number class

Yes, you can do:

<Number(self) >>>> aNumber>

Cheers,

Nico

On Apr 22, 2012, at 3:45 PM, Manfred Kröhnert wrote:

Hi Nico,

Inside verbatim javascript, the ">" character is escaped, exactly like the
"!" in the chunk format.
So, if you write "Number(self) >> aNumber" it will be compiled as
Number(self) > aNumber".

thanks for the explanation.
Any ideas on how to write this line so that it actually evaluates the
shift operator as left shift and not as comparison?

Best,

Manfred

Nicolas Petton
http://www.nicolas-petton.fr

Manfred Kröhnert

Re: Problem extending the Number class

Hmm,

I tried <return Number(self) >>>> aNumber> but the line 4 >> 1 still
evaluates to true instead of 2.

Best,
Manfred

On Sun, Apr 22, 2012 at 4:14 PM, Nicolas Petton
<[hidden email]> wrote:

> Yes, you can do:
>
> <Number(self) >>>> aNumber>
>
> Cheers,
> Nico
>
> On Apr 22, 2012, at 3:45 PM, Manfred Kröhnert wrote:
>
> Hi Nico,
>
> Inside verbatim javascript, the ">" character is escaped, exactly like the
>
> "!" in the chunk format.
>
> So, if you write "Number(self) >> aNumber" it will be compiled as
>
> Number(self) > aNumber".
>
>
> thanks for the explanation.
> Any ideas on how to write this line so that it actually evaluates the
> shift operator as left shift and not as comparison?
>
> Best,
>
> Manfred
>
>
> --
> Nicolas Petton
> http://www.nicolas-petton.fr
>