[Cuis-dev] Parser gets confused when using $| in binary selectors

Fri May 13 09:27:46 PDT 2022

I wouldn’t implement @- *- etc in Number, that would be even more confusing
and reinforce bad style, I think. And ‘- 2’ compiling as -2 is kind of
weird too, maybe shouldn’t be allowed.

On Fri, 13 May 2022 at 10:02 PM Hernan Wilkinson <
hernan.wilkinson at 10pines.com> wrote:

> I would go back to the original behavior. if 1 @- 2 sends the message @-
> to 1 then that message will have to be implemented in Number to get the
> expected behavior, and that will happen with 1 *- 2 and 1 /- 2 and so on.
> This is a case where we have to be pragmatic and we have to prioritize how
> these messages are modeling the arithmetic of numbers.
> For me, this is an example where a special case in the syntax makes it
> more easy to use, closer to the domain problem where those messages are
> used 99% of the time (mathematic) and that will generate the least number
> of surprises.
> We already have problems explaining why 3 + 4 * 5 is not 23 but 35, I can
> not imagine myself explaining why 1 at -2 is not the same as 1 at - 2
> when -2 and - 2 are the same.
> And also, I think we have to give credit to the people that defined this
> behavior a long (Dan Ingalls & co). For sure they had this same discussion
> and they decided to go this way for a reason, and the reason for me has to
> do with what I mentioned earlier.
> Going back to the original behavior makes the behavior of these messages
> more natural and it will maintain compatibility with other Squeak
> descendant Smalltalks.
>
>
> On Fri, May 13, 2022 at 11:38 AM Luciano Notarfrancesco <
> luchiano at gmail.com> wrote:
>
>> Sounds good to me, but not a requirement for my use case, if you think it
>> would complicate the parser you don’t need to do it (at least not for me).
>>
>> On Fri, 13 May 2022 at 9:31 PM Juan Vuletich <JuanVuletich at zoho.com>
>> wrote:
>>
>>> I'm pretty sure I can tweak the parser to treat specially $- as last
>>> char of a binary selector, so that
>>>
>>> 1 at -2 creates a Point.
>>> 1 @ -2 also creates a Point.
>>> 1 @- 2 (note the space between - and 2) sends #@-, whatever that might
>>> mean.
>>>
>>> I know it wouldn't be strictly ANSI, but that shouldn't be too important.
>>>
>>> Do you folks think this would be reasonable behavior?
>>>
>>> Thanks,
>>>
>>>
>>> On 5/13/2022 11:07 AM, Luciano Notarfrancesco via Cuis-dev wrote:
>>>
>>> Can you think of other characters that could be problematic when
>>> allowing them in binary selectors? I don’t use selectors ending with $-,
>>> and I agree that the original behavior is more convenient and intuitive.
>>> The only disadvantage of keeping the original behavior for this case would
>>> be not being ANSI compliant, not a problem for me.
>>>
>>> On Fri, 13 May 2022 at 8:58 PM Luciano Notarfrancesco <
>>> luchiano at gmail.com> wrote:
>>>
>>> Personally I don’t mind if we decide to make an exception for the
>>> special case of $-, but only for that character, because I want to have
>>> more options available for binary operators (for example with $|).
>>>
>>> On Fri, 13 May 2022 at 8:53 PM Hernan Wilkinson <
>>> hernan.wilkinson at 10pines.com> wrote:
>>>
>>> Even more... this change makes things like: 1*-2 or 1/-2 or 1//-2 or
>>> 1+-2, etc etc etc to generate an error.
>>> I think it does not make sense.... any common programmer will expect
>>> 1*-2 to return -2 and not an error.
>>> I think we should get back to the previous behavior.
>>>
>>> What do you think?
>>>
>>> Hernan.
>>>
>>> On Fri, May 13, 2022 at 10:34 AM Hernan Wilkinson <
>>> hernan.wilkinson at 10pines.com> wrote:
>>>
>>> Hi all!
>>>  I'm just wondering why you guys think that having @- as a unary
>>> selector is better than interpreting it as valid for a negative y of a
>>> point...
>>>  I mean, it is much more common to write 1 at -1 as a point whose y is -1
>>> than to use @- as a selector...
>>>  Newcomers will have bit time problems to understand why 1 at -1 does not
>>> generate a point with a -1 as the y, unless the @- message is implemented
>>> in Point to create a point with the negation of the parameter which is for
>>> me an unnecessary indirection...
>>>  I mean, what other class is going to implement a message such as @- ?
>>>  It seems to me more useful the behavior we had previous to this change.
>>>
>>> Hernan.
>>>
>>>
>>> On Fri, May 13, 2022 at 9:52 AM Luciano Notarfrancesco via Cuis-dev <
>>> cuis-dev at lists.cuis.st> wrote:
>>>
>>> If you don't mind, I think these printOns look better (either one)
>>>
>>> On Fri, May 13, 2022 at 2:36 AM Luciano Notarfrancesco <
>>> luchiano at gmail.com> wrote:
>>>
>>> Oh, great, thanks! I was just thinking that “1@(-1)” could have been a
>>> better choice for the fix, and that maybe we should have a preference to
>>> avoid overwriting timestamp and other people’s initials when we do trivial
>>> changes like this.
>>>
>>>
>>> On Fri, 13 May 2022 at 3:41 AM Juan Vuletich <JuanVuletich at zoho.com>
>>> wrote:
>>>
>>> Thanks Folks!
>>>
>>> Luciano, I just pushed your changes. I also found an instance of '\\-'
>>> that I fixed too. There are several changes required for optional packages
>>> in the Cuis-Smalltalk organization. Will push them tomorrow.
>>>
>>> WRT to Decompiler, decompiled code is actually OK, with a space after
>>> binary selectors. What was wrong was the #storeString of literal Points.
>>> Fixed Point>>#printOn: for that. Now DecompilerTests pass.
>>>
>>> Cheers!
>>>
>>>
>>> On 5/9/2022 3:21 PM, Luciano Notarfrancesco via Cuis-dev wrote:
>>>
>>> Martin,
>>> Thanks for the very detailed explanation! I went ahead and replaced '@-'
>>> with '@ -' in the image and the tests. There are still 10 tests producing
>>> errors because the decompiler decompiles it without the space, tho.
>>>
>>>
>>> On Mon, May 9, 2022 at 5:04 PM Martin McClure <martin at hand2mouse.com>
>>> wrote:
>>>
>>> The ANSI Smalltalk grammar says that "@-" should be a valid binary
>>> selector, and would require whitespace in "1@ -1" to interpret the
>>> argument as a literal negative one.
>>>
>>> The Blue Book grammar, though, does not allow "@-" as a binary selector.
>>> The Blue Book grammar, as printed, also does not allow "," as a binary
>>> selector, even though that was clearly used as a binary selector in
>>> Smalltalk-80. The Blue Book grammar also does not talk about whitespace at
>>> all, even though that is clearly required in some places, so the Blue Book
>>> is a bit fuzzier than one would want as a grammar reference.
>>>
>>> Going with ANSI-like grammar and putting a space in expressions like "1
>>> @- 1" makes more sense to me. Allows more valid selectors, and the code is
>>> more readable with the whitespace.
>>>
>>> Regards,
>>> -Martin
>>>
>>> On 5/9/22 03:48, Luciano Notarfrancesco via Cuis-dev wrote:
>>>
>>> After this change '1 at -1' is parsed as a binary message #@-, and this
>>> causes some base image tests to fail. Should we add a space between @ and
>>> -1 or should we fix the parser?
>>>
>>> On Fri, May 6, 2022 at 1:56 PM Luciano Notarfrancesco <
>>> luchiano at gmail.com> wrote:
>>>
>>> That was quick. Thanks a lot!
>>>
>>> On Fri, 6 May 2022 at 8:55 PM Juan Vuletich <JuanVuletich at zoho.com>
>>> wrote:
>>>
>>> On 5/6/2022 10:48 AM, Luciano Notarfrancesco via Cuis-dev wrote:
>>>
>>> I’m not sure I was clear, I meant a method implementing those messages,
>>> not sending those messages.
>>>
>>> On Fri, 6 May 2022 at 1:22 PM Luciano Notarfrancesco <luchiano at gmail.com>
>>> wrote:
>>>
>>> I’m getting “Argument name expected” when trying to compile a method
>>> with selector <|. On the other hand, |>, | and || all compile fine as
>>> binary selectors, but || breaks syntax highlighting.
>>>
>>>
>>> Sure. Fixes at GitHub now.
>>>
>>> A small detail: Now an empty temporal declaration `||` is parsed as a
>>> binary selector, and therefore marked as invalid. Not a big deal. We'd just
>>> remove any such.
>>>
>>> Cheers,
>>>
>>> --
>>> Juan Vuletichwww.cuis-smalltalk.orghttps://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Devhttps://github.com/jvuletichhttps://www.linkedin.com/in/juan-vuletich-75611b3https://independent.academia.edu/JuanVuletichhttps://www.researchgate.net/profile/Juan-Vuletichhttps://patents.justia.com/inventor/juan-manuel-vuletichhttps://twitter.com/JuanVuletich
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Juan Vuletichwww.cuis-smalltalk.orghttps://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Devhttps://github.com/jvuletichhttps://www.linkedin.com/in/juan-vuletich-75611b3https://independent.academia.edu/JuanVuletichhttps://www.researchgate.net/profile/Juan-Vuletichhttps://patents.justia.com/inventor/juan-manuel-vuletichhttps://twitter.com/JuanVuletich
>>>
>>> --
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>>> Cuis-dev at lists.cuis.st
>>> https://lists.cuis.st/mailman/listinfo/cuis-dev
>>>
>>>
>>>
>>> --
>>> <https://10pines.com/> Hernán Wilkinson Software Developer & Coach
>>>
>>> Alem 896, Floor 6, Buenos Aires, Argentina
>>>
>>> +54 11 6091 3125
>>>
>>> @HernanWilkinson
>>>
>>>
>>>
>>> --
>>> <https://10pines.com/> Hernán Wilkinson Software Developer & Coach
>>>
>>> Alem 896, Floor 6, Buenos Aires, Argentina
>>>
>>> +54 11 6091 3125
>>>
>>> @HernanWilkinson
>>>
>>>
>>>
>>> --
>>> Juan Vuletichwww.cuis-smalltalk.orghttps://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Devhttps://github.com/jvuletichhttps://www.linkedin.com/in/juan-vuletich-75611b3https://independent.academia.edu/JuanVuletichhttps://www.researchgate.net/profile/Juan-Vuletichhttps://patents.justia.com/inventor/juan-manuel-vuletichhttps://twitter.com/JuanVuletich
>>>
>>>
>
> --
> <https://10pines.com/>Hernán WilkinsonSoftware Developer & Coach
>
> Alem 896, Floor 6, Buenos Aires, Argentina
>
> +54 11 6091 3125
>
> @HernanWilkinson
>
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